ChatGPT answers, unedited

I’d start with Brevo for a cash-constrained SaaS. Its pricing is send-based rather than simply charging more for every subscriber, which can be attractive as your user base grows. The free tier supports 100,000 stored contacts, 300 emails/day, basic analytics, and automation for up to 2,000 contacts; paid plans start at $9/month. Brevo Help Omnisend

• Brevo: Best budget fit; onboarding automation + analytics + transactional email.
• Loops: Better if product-event-triggered SaaS onboarding is central, but paid pricing becomes $49/month around 5,000 contacts. Zapier
• MailerLite: Worth considering for marketing-heavy email, but its contact-based pricing becomes less attractive as your list grows. Omnisend

For tight runway, I'd avoid Customer.io/ActiveCampaign initially unless you genuinely need their deeper automation.

For an early-stage SaaS with a tight runway, I’d avoid the “enterprise lifecycle marketing” tools first (for example, platforms that become expensive once you have a few thousand contacts). Your sweet spot is usually: cheap base cost + onboarding automation + event/segment analytics + room to grow.

Here are the options I’d shortlist:

My practical picks by stage

If you have <5,000 users and need onboarding ASAP

Pick: Loops

• Good match for SaaS because emails can be triggered from product events (signup, activated feature, invited teammate, trial ending). Zapier
• A typical setup:

• Day 0: welcome + “get started”
• Day 1: activation checklist
• Day 3: feature education
• Day 7: case study/use case
• Trial expiry: conversion nudge

If you mainly need cheap marketing + onboarding

Pick: Brevo

• Good runway choice because you’re less exposed to a growing subscriber bill.
• Works well for:

• signup confirmation
• onboarding drip
• product announcements
• re-engagement campaigns Brevo

If you’re non-technical and want to ship flows yourself

Pick: MailerLite

• Easy automation builder.
• Good for founder-led marketing teams that don’t want engineering involvement. MailerLite

What I’d avoid initially

• HubSpot Marketing Hub: great ecosystem, but costs can jump quickly once you need serious automation.
• Customer.io/Userlist-style tools: excellent lifecycle capabilities, but often priced for companies that already have meaningful revenue or a larger marketing budget. EmailToolScout
• Mailchimp: fine for newsletters, but many SaaS teams find the pricing/automation tradeoff less attractive as they grow.

A lean SaaS stack I’d consider

• Product events: your app analytics (PostHog, Segment, etc.)
• Lifecycle email: Loops or Brevo
• Transactional email: keep separate if needed (e.g., password resets)
• Measure:

• activation rate
• trial-to-paid conversion
• onboarding email click → product action
• churn/reactivation

If you tell me your approximate user count (e.g., <1k, 1–10k, 10k+) and whether you need behavior-triggered emails (“user didn’t invite a teammate”) vs simple drip sequences, I can narrow this to one or two choices.

My pick: brevo.com. Its pricing is based primarily on email volume rather than subscriber count, and the $18/month Standard tier includes unlimited-contact automation, analytics, A/B testing, and event tracking. Brevo Help Brevo

• Brevo: Best fit if your subscriber base may grow faster than email volume.
• MailerLite: Cheaper initially—free up to 250 subscribers, then Comfort starts at $12/month—but pricing scales with active subscribers. MailerLite MailerLite
• Verdict: For a tight-runway SaaS, I'd start with Brevo to avoid painful per-subscriber scaling.

For a cash-constrained early-stage SaaS, I’d shortlist Brevo first, with Loops as the SaaS-native alternative.

My pick: brevo.com

The big advantage is that Brevo prices primarily by email volume rather than by subscriber count. That’s unusually attractive for SaaS, where you can accumulate thousands of dormant users without wanting your bill to explode. Its free tier supports up to 100,000 stored contacts and 300 emails/day; paid Starter begins at $9/month. Brevo Help Brevo

For onboarding, I'd use the Standard plan ($18/month) once you need serious automation: it includes unlimited-contact marketing automation, multi-step workflows, event/web tracking, A/B testing, and advanced reporting. Brevo

Why it fits your situation:

• Low fixed cost while you're small.
• Subscriber growth doesn't automatically increase your bill.
• Can handle marketing and transactional email in one platform.
• Good enough analytics for activation/onboarding experiments.
• You can start free and only move to $18 when automation requirements justify it.

Runner-up: loops.so

If your onboarding is heavily product-event-driven—e.g. signed up → didn't create project → created project → invited teammate—I'd look seriously at Loops. It's purpose-built around SaaS lifecycle email and event-triggered automation. Its free tier is reported at 1,000 contacts/4,000 sends per month, with paid plans becoming contact-based. Coldletter

The catch is exactly your concern: contact-based pricing becomes less attractive as your user base grows, even if only a small percentage of users are actively engaged. EveryAny.One

What I'd avoid for now

• Customer.io — excellent for sophisticated behavioral lifecycle messaging, but probably unnecessary overhead while runway is tight.
• Klaviyo — great product, but its pricing curve is much harder to justify for SaaS; it's more compelling for ecommerce.
• Mailchimp — easy to start with, but contact-based pricing makes it less attractive once your SaaS accumulates inactive users.

The decision rule

Bottom line: I'd start with Brevo, build your onboarding sequence there, and keep the architecture simple. At your stage, spending $18/month on a tool that won't punish you for accumulating subscribers is much more runway-friendly than adopting a sophisticated lifecycle platform prematurely. Brevo Help Brevo

For a cash-constrained early-stage SaaS, I’d shortlist Brevo first, with Loops as the better SaaS-native alternative.

🥇 My pick: Brevo

Brevo's pricing is particularly attractive for SaaS because you're primarily paying for emails sent rather than the number of contacts stored. Its free plan currently allows up to 300 emails/day, while the Starter plan starts around $9/month. Its Standard tier adds unlimited multi-step automation, event tracking, segmentation, A/B testing, and deeper reporting. Brevo EveryAny.One

brevo.com

That's a big deal if, for example, you have 10,000 registered users but only 2,000 active users. Subscriber-priced tools can make that dormant-user database surprisingly expensive.

I'd use it for something like:

• Day 0: Welcome + "here's how to get started"
• Day 1: Key feature walkthrough
• Day 3: "Have you completed X?"
• Day 5: Use-case/customer example
• Day 7: Trial/value reminder
• Triggered: User completes X → advance sequence
• Triggered: User hasn't completed X → intervention email

🥈 If product events matter more: Loops

Loops is purpose-built around SaaS lifecycle email and supports event-driven campaigns, transactional email, audience filtering, and product-oriented analytics. Current reporting puts its free tier at roughly 1,000 contacts / 4,000 sends, with paid plans starting around $49/month. coldletter.com EmailToolScout

loops.so

I'd choose Loops over Brevo if your onboarding logic is heavily behavioral:

signup → didn't create project → remind them → created project → teach collaboration → invited teammate → activate next feature

That's closer to the way a SaaS actually thinks about lifecycle messaging.

What I'd avoid for now

Customer.io is excellent, but its ~$100/month starting point is hard to justify when runway is the constraint. SaaS Dealer TechVendorIndex

MailerLite is also good and inexpensive, but its subscriber-based pricing is less attractive if your SaaS accumulates lots of inactive users. SaaS Scored

Bottom line

Pick Brevo if your priority is lowest cost + decent automation + analytics + a growing user database.

Pick Loops if your priority is best SaaS-specific onboarding/event automation and you're comfortable paying more once you outgrow its free tier.

If you tell me roughly how many users you have now, monthly new signups, and how many onboarding emails each user gets, I can calculate which one will actually be cheapest at 1K / 5K / 10K / 50K users.

For an early-stage SaaS with a tight runway, I’d optimize for (1) low fixed cost, (2) behavioral triggers, (3) onboarding analytics, and (4) avoiding contact-count pricing traps. The cheapest “newsletter” tools often become expensive once you have thousands of users. Stackmatix

Here are the options I’d shortlist:

My recommendation by stage

If you have <5,000 users

Start with Loops or Brevo.

• Build: - Day 0: welcome + “first value” email
• Day 1–3: activation nudges
• Day 7: feature discovery
• Day 14: trial conversion / upgrade prompt
• Win-back sequence for inactive users

You probably don’t need a heavy lifecycle platform yet. Email Platform Review

If your onboarding depends on product behavior

Example:

• “User created account but never invited a teammate”
• “User uploaded 3 files but not 10”
• “Trial ends in 5 days and they haven’t activated”

Use Customer.io if you can justify the cost, or a cheaper event-based alternative. This is where generic newsletter tools start feeling limiting. Stackmatix

If runway is extremely tight

I’d look at:

1. Brevo — lowest-cost general-purpose option.
2. Loops — better SaaS experience.
3. FlowingMail — attractive if avoiding subscriber-based pricing is the priority. FlowingMail

What I’d avoid early

• HubSpot Marketing Hub — great ecosystem, but automation features can become expensive quickly.
• Klaviyo — excellent for ecommerce, usually not the best economics for SaaS onboarding.
• Building on a basic newsletter tool and later migrating without tracking events — you’ll lose behavioral history.

My default pick for a pre-Series A SaaS would be:

→ Loops if you want fast setup and SaaS-native workflows.
→ Brevo if cost is the absolute constraint.
→ Customer.io once onboarding complexity becomes a growth bottleneck.

A useful rule: don’t pay for “marketing automation” until you know your activation events. Track the 2–3 product actions that correlate with retention, then automate around those.

For a cash-constrained early-stage SaaS, I’d shortlist Loops, Brevo, and MailerLite. The key distinction is whether you’re optimizing for SaaS product onboarding or general email marketing.

My pick: Loops

loops.so is probably the best fit if your main use case is product-led onboarding.

• Built specifically around SaaS lifecycle/product email: onboarding, trials, re-engagement, product updates, etc. Loops Loops
• Workflows can react to events and contact properties, which is much more natural for SaaS onboarding than a traditional newsletter tool.
• Free tier: 1,000 contacts + 4,000 emails/month, with workflows, events, and contact properties included. Loops
• You can use it for marketing + lifecycle + transactional email, potentially reducing the number of tools you need. Loops

Caveat: if your user base grows substantially, I'd compare the next pricing tier carefully before committing.

Best value if you want more contacts: Brevo

brevo.com is particularly attractive if your constraint is subscriber count rather than email volume.

• Free plan stores up to 100,000 contacts, although you're limited to 300 emails/day.
• Free includes basic analytics and automation for up to 2,000 contacts.
• Starter starts at $9/month.
• Standard starts at $18/month and adds unlimited-contact marketing automation, A/B testing, and advanced reporting. Brevo Help

That's a compelling pricing model for a SaaS with lots of registered-but-infrequently-emailed users.

Best simple all-rounder: MailerLite

mailerlite.com is my choice if you want marketing + onboarding + landing pages/forms in one relatively simple product.

• Free: 250 subscribers, 2,500 emails/month, and 3 automations.
• Comfort starts at $12/month, with 50 automations and 10× your subscriber count in monthly email capacity.
• Power starts at $25/month with unlimited monthly email and automations. MailerLite MailerLite
• It has automation reporting, comparative reporting, click maps, segmentation, and A/B testing. MailerLite

What I'd do with a tight runway

My recommendation: start with Loops if your onboarding sequence is things like signup → activate → use feature X → invite teammate → convert. It's purpose-built around that lifecycle. If you expect a large contact database quickly and want to minimize subscriber-based pricing, choose Brevo instead.

One thing I'd avoid at your stage: paying for an expensive Customer.io/HubSpot-style platform just because it has sophisticated journey tooling. You probably won't need that complexity until your activation experiments become significantly more sophisticated.

For an early-stage SaaS with a tight runway, I’d avoid tools that charge aggressively as your contact list grows (a common pain point with traditional ESPs). I’d optimize for:

• Lifecycle/onboarding sequences (welcome → activation → trial conversion)
• Event-based triggers (e.g., “created first project,” “invited teammate”)
• Basic analytics (opens, clicks, activation/conversion tracking)
• Low fixed cost as you grow

My shortlist:

Email Platform Review Sequenzy## My recommendation by stage

1. Pre-PMF / <5k users: start cheap

Pick: Loops or Brevo

You probably only need:

• Day 0: Welcome + “first action” email
• Day 1–3: Activation nudges
• Day 7: Feature education
• Trial ending: Conversion sequence
• Inactive user: Re-engagement

Don’t build 30 branches yet. A simple sequence with good copy and one or two behavioral triggers will outperform a complicated automation nobody maintains.

2. Developer-led SaaS with product events

Pick: Customer.io when you need it

If your onboarding depends on events like:

• “uploaded first file”
• “created first dashboard”
• “invited teammate”
• “hit usage limit”

then Customer.io becomes attractive because it is designed around behavioral workflows. The downside is cost and setup overhead. Email Platform Review

3. Extreme runway protection

Consider a stack like:

• Amazon Web Services Simple Email Service (SES) for sending
• A lightweight automation layer you control
• Analytics in your existing product analytics tool

This can get very cheap at scale, but it requires engineering time.

What I would avoid right now

• HubSpot Marketing Hub paid tiers — powerful, but often expensive for a startup just needing onboarding email.
• Intercom — excellent product, but can consume a meaningful chunk of runway.
• Heavy enterprise lifecycle tools — you likely won’t use enough of the complexity.

If I were choosing for a bootstrapped SaaS

• Fastest + cheapest: Loops
• Best budget all-rounder: Brevo
• Best long-term SaaS lifecycle tool: Customer.io
• Lowest possible email infrastructure cost: SES + your own automation

A good rule: don’t pay for “marketing automation” until you have enough users that improving activation is worth more than the monthly bill. In the first phase, prioritize tracking one activation event and getting a tight 5–7 email onboarding loop running.

For an early-stage SaaS with tight runway, I’d avoid tools that become expensive purely because your signup list grows. The best fit depends on whether you need simple lifecycle onboarding or deep product-event automation.

My shortlist

My recommendation by stage

Pre-seed / MVP (0–5k users)

Pick:

1. Brevo — best runway protection.
2. MailerLite — if your onboarding is mostly “signup → educate → convert.”
3. Loops — if you want a SaaS-native experience and can afford ~$50/month. Email Platform Review Sequenzy

A good MVP onboarding stack:

• Welcome email immediately
• Day 1: “Get your first win”
• Day 3: feature discovery
• Day 7: case study/social proof
• Day 14: trial conversion nudge
• Re-engagement after inactivity

You probably don’t need a sophisticated journey builder yet.

Product-led SaaS with behavioral triggers

If your emails depend on app events:

• User signs up but never completes setup
• User invites teammates
• User hits usage limits
• User hasn’t logged in for 14 days

Then move toward Customer.io or Loops. Customer.io is especially strong when engineering can send user events into the platform. Stackmatix Email Platform Review

What I would avoid right now

• hubspot.com Marketing Hub paid tiers — powerful, but often too expensive before you have a real marketing team.
• klaviyo.com — excellent for ecommerce, usually not the best SaaS onboarding value.
• Enterprise lifecycle tools like braze.com — save those for much later.

If this were my SaaS with a tight runway

I’d choose:

• <$25/month budget: Brevo or MailerLite
• ~$50/month budget: Loops
• Need serious behavioral onboarding: Customer.io (only when activation metrics justify it)

The biggest cost saver is keeping your marketing emails and product-triggered emails separate if needed: don’t pay enterprise lifecycle pricing just because you need a five-email onboarding drip. day3

If you share your approximate user count (e.g., 500 signups vs 50k), whether you have a free trial, and whether emails need to trigger from app events, I can narrow this to one choice.

For a tight-runway early-stage SaaS, I’d shortlist Brevo, Loops, and MailerLite—but they fit different growth patterns.

My pick: Brevo

Brevo is particularly attractive if you're accumulating users faster than you're sending emails. Its pricing is based primarily on email volume rather than the number of contacts you store, so a 10,000-person database doesn't automatically become a huge bill. Current comparisons put the free tier at 300 emails/day and paid plans starting around $9/month. EveryAny.One Stackmerit

That makes it a good runway-conscious choice for:

• Welcome/onboarding sequences
• Trial-ending reminders
• Feature education
• Segmented campaigns
• Basic engagement analytics
• A growing database where lots of users aren't receiving emails every month

The caveat: if you want highly sophisticated behavior-triggered lifecycle automation—e.g. "user signed up → hasn't created a project after 24 hours → send A; created project but hasn't invited teammate → send B"—I'd choose Loops instead.

When I'd pay for Loops

Loops is much more SaaS-native. It supports product-event-driven campaigns and lifecycle email, and its free tier is reported at 1,000 contacts / 4,000 sends per month, with paid pricing starting around $49/month. coldletter.com coldletter.com

So I'd use Loops if activation/retention is the core job of your email, rather than newsletters.

The downside for your particular constraint is important: its pricing is contact-based, so eventually you're paying for users sitting in your database even if they're not actively receiving mail. EveryAny.One

When I'd choose MailerLite

If your onboarding is basically:

signup → Day 0 welcome → Day 2 getting-started → Day 5 key feature → Day 10 upgrade CTA

…and you don't need sophisticated product-event triggers, MailerLite is probably the simplest option. It's inexpensive and has a solid automation builder, but its subscriber-based pricing becomes less attractive as your user database grows. EmailToolScout EveryAny.One

What I'd avoid right now

I wouldn't start with Customer.io unless you already know you need its advanced behavioral orchestration. It's excellent for SaaS lifecycle messaging, but current pricing starts around $100/month for 5,000 profiles, which is hard to justify when runway is the constraint. coldletter.com

Bottom line:
Brevo if minimizing monthly cost is #1. Loops if product-event-driven onboarding is #1. MailerLite if you want the simplest cheap drip system.

If you tell me roughly how many users/contacts you have now and how many emails you expect to send per month, I can calculate which one will actually be cheapest at 1K → 5K → 10K → 50K users.

For a cash-constrained early-stage SaaS, I’d shortlist these three:

My recommendation: Brevo

For your specific constraint—tight runway + onboarding sequences + analytics + avoiding painful per-subscriber pricing—I'd start with Brevo.

Its current free tier allows up to 100,000 stored contacts, although you're limited to 300 emails/day and automation is limited to 2,000 contacts. Its Starter plan starts at $9/month, while Standard starts at $18/month and removes the automation contact limit while adding more advanced reporting and A/B testing. Brevo Help

The important distinction is that Brevo's economics are largely send-volume based, rather than charging you increasingly just because your database gets larger. That's particularly attractive for SaaS products where you may accumulate lots of inactive/free users. Brevo Help EveryAny.One

When I'd pick Loops instead

If your onboarding needs to be behavior-driven, I'd seriously consider Loops.

For example:

• User signs up → onboarding sequence
• Completes setup → skip setup emails
• Invites teammate → move to activation sequence
• Doesn't use feature X after 3 days → send targeted nudge
• Upgrades → stop trial emails and start customer onboarding

That's much closer to the SaaS lifecycle model than traditional newsletter software. Loops is explicitly designed around product events and lifecycle messaging. Loops

Its free tier is currently around 1,000 contacts, with paid pricing starting around $49/month, so I'd choose it when the value of event-driven automation justifies the higher starting cost. coldletter.com

What I'd avoid for now

I wouldn't start with Customer.io, HubSpot, or similar heavyweight lifecycle platforms unless you already have substantial revenue or unusually complex automation requirements. They can be excellent, but you're paying for sophistication you may not need yet.

Bottom line:
Brevo if runway is the overriding concern. Loops if product-event-driven onboarding is strategically important. MailerLite if you mainly need straightforward drip sequences and newsletters.

If you tell me roughly how many contacts you have now, monthly new signups, and emails/user/month, I can calculate the approximate monthly cost of Brevo vs Loops vs MailerLite at 1k/5k/10k/50k users.

For a cash-constrained early-stage SaaS, I’d shortlist these three:

• loops.so — my first choice for SaaS. It’s specifically built around product/lifecycle email: onboarding, trial conversion, re-engagement, event-triggered workflows, and segmentation. The free tier includes 1,000 contacts + 4,000 emails/month, with workflows and events included, and it doesn't expire. Loops Loops
• brevo.com — best if your list may grow faster. Its pricing is primarily tied to email volume rather than simply subscriber count. Free includes basic analytics and automation for up to 2,000 contacts; Standard starts at $18/month and adds unlimited-contact automation, A/B testing, advanced reporting, and event tracking. Brevo Help Brevo Help
• mailerlite.com — best simple/general-purpose option. Strong automation, segmentation, testing and analytics, with paid plans starting at $12/month. However, pricing scales with active subscribers, so it becomes less attractive if your user base grows substantially. MailerLite MailerLite

What I'd pick

Loops if your primary need is SaaS onboarding. You can do something like:

Signup → Welcome → +1 day setup → +3 days key feature → branch on activation → re-engage inactive users → trial-expiry sequence

Its event-based model is particularly useful because you can trigger journeys from actual product behavior rather than just "joined mailing list." Loops

Brevo would be my pick if you expect a large contact database but relatively modest email volume. Its pricing structure is unusually favorable for that situation. Brevo Help

One caveat: if you're sending highly personalized lifecycle emails based on lots of product events, I'd favor a SaaS-native tool like Loops over a traditional newsletter platform. You can keep your transactional provider separate if needed; Loops explicitly supports transactional, marketing, and product email. Loops Loops

If you tell me roughly how many users you have now, expected users in 12 months, and monthly email volume, I can calculate the likely 12-month cost for Loops vs. Brevo vs. MailerLite.

For an early-stage SaaS with a tight runway, I’d avoid the big “marketing automation suites” unless you already have thousands of active users and complex journeys. You mainly need:

• signup-triggered onboarding sequences
• behavioral/event triggers (e.g., “created first project,” “invited teammate”)
• basic conversion analytics (opens, clicks, activation)
• reasonable scaling without your bill exploding with every 1,000 contacts

My shortlist:

Email Platform Review Email Sequence Tools## My recommendation by stage

If you have <5,000 users

Start with Loops or Brevo.

A practical setup:

1. Signup → welcome email immediately
2. Day 1 → “complete your first key action”
3. Day 3 → case study/use case
4. Day 7 → feature discovery
5. Trial ending → conversion email

Keep product analytics in your existing stack (PostHog, Amplitude, Mixpanel, etc.) and use email analytics only for engagement.

If activation is your biggest problem

Consider a SaaS-specific lifecycle tool like customer.io once you have enough volume to justify it. It shines when emails depend on product events rather than just time delays. Email Platform Review

If you are extremely cost constrained

A lower-cost stack can be:

• aws.amazon.com for sending
• a lightweight automation layer
• your own event tracking

This is cheapest at scale, but costs engineering time.

What I would avoid early

• hubspot.com — powerful, but pricing can jump quickly as needs grow.
• intercom.com — excellent for support + messaging, but usually expensive for a bootstrapped onboarding-only use case.
• Enterprise lifecycle tools before you have enough user behavior data.

For a typical seed-stage SaaS, I’d start with Loops (simplicity) or Brevo (lowest cost), then migrate to Customer.io when onboarding logic becomes a competitive advantage. Email Platform Review Email Sequence Tools

If you share your rough numbers (monthly signups, current users, B2B vs B2C, and whether you track events like “activated”), I can narrow this to one choice.

For a tight-runway SaaS, I’d shortlist these three, with Brevo as my default pick:

My recommendation

Start with Brevo Standard if your priority is minimizing costs as your SaaS user base grows. Its model is unusually favorable when you have lots of contacts but relatively modest email volume: you aren't simply punished for accumulating inactive/free users. Standard includes unlimited marketing automation and advanced reporting. Brevo Help

If you're very early (<250–1,000 users), I'd actually start with MailerLite or Loops' free tier and avoid paying until you have enough traction to justify it.

For a product-led SaaS, my preference would be:

Loops → best product onboarding experience
Brevo → best runway-conscious scaling economics
MailerLite → best cheap general-purpose email platform

One important distinction: if by "onboarding" you mean event-driven product emails such as signed up → hasn't completed setup → send reminder → activated feature → send next lesson, I'd lean Loops. If you mean welcome series + newsletters + lifecycle campaigns + analytics, I'd lean Brevo. Loops Brevo Help

For an early-stage SaaS, I’d shortlist Brevo, Loops, and MailerLite—but they optimize for slightly different things.

My pick: Brevo

For a cash-constrained SaaS, Brevo is probably the best economic fit. Its free tier supports up to 100,000 stored contacts, though automation is capped at 2,000 unique contacts; paid plans start at $9/month, and Standard starts at $18/month with unlimited contacts in marketing automation. Pricing is tied substantially to sending volume rather than simply charging you more for every additional subscriber. Brevo Help Brevo Help

That makes it attractive if you expect your user database to grow faster than the number of emails you actually send.

If product onboarding is the priority: Loops

Loops is particularly compelling for SaaS because it is designed around product/lifecycle email rather than traditional newsletters. It supports event-triggered workflows, branching, contact properties, and onboarding sequences. Its free tier currently includes 1,000 contacts and 4,000 emails/month, without expiring. Loops

I'd pick Loops if your core requirement is something like:

signup → welcome → wait 2 days → check whether activated → send different email → check whether feature used → continue onboarding

rather than primarily newsletters and marketing campaigns.

MailerLite: excellent value, but watch subscriber growth

MailerLite is very inexpensive initially: its current paid plans start at $12/month, and it has visual automations, segmentation, A/B testing and reporting. Its free plan includes 250 subscribers and 2,500 monthly emails. MailerLite MailerLite

The catch for your particular requirement is that pricing scales with active subscribers, so it becomes less attractive if you expect a large free-user base that you want to keep in your email database. MailerLite

What I'd do in your shoes

• <1,000 users + SaaS-specific onboarding: Loops
• Rapidly growing user database + controlled email volume: Brevo
• Mostly newsletters/content + relatively small list: MailerLite
• If runway is extremely tight: start on Brevo or Loops' free tier and don't optimize prematurely for sophisticated marketing features.

One important distinction: don't evaluate these purely by "contacts included." For SaaS, the key metric is cost at 10k, 50k, and 100k users while sending only a handful of lifecycle emails per user. That's where subscriber-based pricing can become painful.

If you tell me roughly how many users you have now, expected users in 12 months, and emails/user/month, I can calculate which one is likely to be cheapest at each stage.

If product onboarding is the priority: Loops

Loops is particularly compelling for SaaS because it is designed around product/lifecycle email rather than traditional newsletters. It supports event-triggered workflows, branching, contact properties, and onboarding sequences. Its free tier currently includes 1,000 contacts and 4,000 emails/month, without expiring. Loops

I'd pick Loops if your core requirement is something like:

signup → welcome → wait 2 days → check whether activated → send different email → check whether feature used → continue onboarding

rather than primarily newsletters and marketing campaigns.

MailerLite: excellent value, but watch subscriber growth

MailerLite is very inexpensive initially: its current paid plans start at $12/month, and it has visual automations, segmentation, A/B testing and reporting. Its free plan includes 250 subscribers and 2,500 monthly emails. mailerlite.com mailerlite.com

The catch for your particular requirement is that pricing scales with active subscribers, so it becomes less attractive if you expect a large free-user base that you want to keep in your email database.

What I'd do in your shoes

For an early-stage SaaS with a tight runway, I’d avoid the classic “cheap at 1,000 contacts, painful at 20,000” traps. You want:

• Behavior-triggered onboarding (signup → activated → trial ending → re-engagement)
• Product event tracking (not just list-based newsletters)
• Analytics tied to activation/conversion
• Predictable pricing that won’t punish growth

My shortlist:

www.emailplatformreview.comwww.sequenzy.com

My picks by stage

1. Pre-product-market fit / <5k users

• Start with Loops or MailerLite.
• Build:
  • Day 0: welcome + activation goal
  • Day 1: “complete your first key action”
  • Day 3: feature education
  • Day 7: case study/use case
  • Trial ending: conversion sequence

Loops is specifically positioned for early SaaS teams needing simple onboarding sequences, while MailerLite is better if you also need newsletters and marketing campaigns. www.emailplatformreview.com

2. PLG SaaS with meaningful user behavior data

• Consider Customer.io once you need flows like:
  • “User signed up but didn’t invite teammates”
  • “Connected integration but never used feature X”
  • “High usage → upsell”

It’s powerful, but I wouldn’t burn runway on it before you have enough volume to optimize. www.emailplatformreview.comwww.sequenzy.com

3. Engineering-heavy team that wants maximum cost efficiency

• Use Amazon SES for sending + your own event layer, or a lightweight automation tool.
• Cheapest long-term, but you’re trading money for engineering time.

What I’d probably do with a tight runway

1. Start with Loops or Brevo
2. Instrument 5–10 product events:
   • signup_completed
   • first_project_created
   • invited_teammate
   • integration_connected
   • subscription_started
3. Only send emails based on those events
4. Move to Customer.io when you can prove email-driven activation is worth optimizing

One caution: don’t optimize for “lowest monthly price” alone. A $20/month tool that can’t tell you whether onboarding emails improve activation is usually more expensive than a $50/month tool with useful conversion analytics. flowingmail.com

For a typical early SaaS, my ranking would be:

1. Loops — best balance of cheap + SaaS-friendly
2. Brevo — best budget all-rounder
3. Customer.io — best when you have traction
4. Amazon SES stack — best if engineering time is abundant
5. MailerLite — best if your needs are mostly marketing emails

For an early-stage SaaS with a tight runway, I’d shortlist Brevo and Loops, with Brevo as the cost-first choice.

My pick: Brevo

The key advantage is its pricing model. Brevo doesn't charge you simply for having a large database of users; its paid plans are primarily based on email volume. Its free tier currently allows unlimited contacts but caps sending at 300 emails/day, while Starter begins around $9/month for 5,000 monthly emails. Brevo Help EveryAny.One

That is particularly attractive for SaaS because you might have 10,000 registered users but only email a fraction of them during onboarding. A conventional per-subscriber platform can punish you for retaining those inactive users.

You can build sequences such as:

• Signup → welcome
• Day 1 → activation tip
• Day 3 → feature education
• Day 5 → "haven't activated?" nudge
• Day 7 → upgrade/trial reminder
• Activated → stop onboarding and enter another segment

When I'd choose Loops instead

If your onboarding needs to be deeply product-event-driven, I'd pay the extra money for loops.so.

Loops is specifically built around SaaS lifecycle email and supports event-triggered campaigns, audience properties, transactional email, and API-driven workflows. Its free plan currently covers 1,000 contacts and 4,000 sends/month; the paid tier is around $49/month for 5,000 contacts. Zapier coldletter.com

So, for example, you can make logic like:

signed_up → wait 2 days → if created_project = false → send activation email → if created_project = true → skip it.

That's closer to what you'd eventually want from Customer.io, without starting at a ~$100/month platform. EmailToolScout

Bottom line

If runway is the overriding constraint: Brevo.

If activation/onboarding sophistication is the overriding constraint: Loops.

If you mainly need conventional email marketing and want simplicity: MailerLite.

I would not start with Customer.io, HubSpot, or Klaviyo for this particular situation. They're powerful, but you're likely paying for complexity before you have the volume/team that benefits from it.

One caveat: if your SaaS has lots of inactive users, Brevo's send-based pricing is especially compelling. If you expect to email virtually every user several times per week, the economics can flip toward a contact-based platform like Loops. EveryAny.One

For an early-stage SaaS, I’d shortlist Brevo, Loops, and MailerLite. The key is avoiding tools that charge aggressively as your user base grows.

My pick: brevo.com

Best overall for a tight runway. Brevo’s pricing is primarily tied to email volume rather than simply the number of contacts, which can be much friendlier for SaaS products with lots of inactive/low-frequency users. Its free tier supports up to 100,000 stored contacts, though automation is limited to 2,000 contacts; the Starter plan starts at $9/month, while Standard starts at $18/month and adds unlimited-contact marketing automation, A/B testing, and advanced analytics. Brevo Help Brevo

For onboarding, you can build multi-step workflows triggered by signup or behavioral events, and Standard includes web/event tracking. Brevo Brevo

Best SaaS-native option: loops.so

If your emails are primarily product/lifecycle emails rather than newsletters, I'd seriously consider Loops. It is designed specifically around SaaS onboarding: you can trigger workflows from events such as trial_started, branch based on whether someone activated, and send different messages based on product behavior. Loops

Its free tier currently includes 1,000 contacts and 4,000 emails/month, with workflows, events, and contact properties included. Loops

The downside is that you'll want to check its pricing carefully as your user base grows; Brevo is more compelling if minimizing contact-based pricing is the overriding concern.

Best simple marketing platform: mailerlite.com

MailerLite is attractive if you want onboarding + newsletters + landing pages + conventional marketing analytics in one inexpensive package. Its free tier currently supports 250 subscribers and 2,500 monthly emails with three automations. Paid Comfort starts at $12/month and includes 50 automations; Power starts at $25/month with unlimited automations and unlimited monthly emails. MailerLite MailerLite

The catch for your particular situation: it explicitly prices based on active subscriber count, so it becomes less attractive if your SaaS gets tens of thousands of users. MailerLite

What I'd choose

For your situation, I'd start with Brevo unless your email program is almost entirely product onboarding. If it's mostly things like “Welcome → Complete setup → Try feature X → You're halfway there → Upgrade”, I'd start with Loops instead.

One important architecture decision: keep your transactional/product-triggered emails and your marketing/newsletter list conceptually separate from day one. That makes it much easier to switch vendors later without rebuilding your entire customer lifecycle.

For a cash-constrained early-stage SaaS, I’d shortlist Brevo and Loops, with Brevo as the safest budget pick and Loops as the better SaaS-native pick.

My recommendation

1. Brevo — best if runway is the #1 concern.
Its Standard plan includes unlimited automated multi-step workflows, A/B testing, and advanced reporting/analytics. Crucially, Brevo doesn't make your bill primarily depend on the number of contacts you store, which can be attractive if you have lots of inactive/free users. Brevo Brevo Help

2. Loops — best if onboarding is tightly tied to product behavior.
Loops is purpose-built around SaaS lifecycle email: you can trigger workflows from events such as trial_started, activation, property changes, etc., and build branches/timers visually. Its free tier currently covers 1,000 contacts and 4,000 emails/month. Loops

The important cost distinction: Loops becomes contact-based as you grow, whereas Brevo's economics are more send-oriented. A recent comparison found Loops at about $99/month for 10k contacts, while Brevo's Starter begins at $9/month based on email volume. EveryAny.One

What I'd do in your shoes

• <1,000 users and technical/product-event onboarding: start with Loops free.
• Lots of free users or a rapidly growing contact database: start with Brevo.
• Mostly simple “Day 0 → Day 2 → Day 5” onboarding: Brevo is probably plenty.
• “Signed up → didn't activate → used feature X → trial ending → upgraded” workflows: Loops is worth the tradeoff.

I wouldn't start with Customer.io, HubSpot, or Klaviyo on a tight runway unless you already need their more sophisticated capabilities. For an early SaaS, you're likely paying for complexity before you need it.

brevo.com
loops.so

If you tell me roughly how many contacts you have now, monthly new signups, and emails/user/month, I can do the actual 12-month cost comparison and tell you which will stay cheapest as you scale.

For an early-stage SaaS, I’d shortlist Loops and Brevo first. The key distinction is whether you want a SaaS-native lifecycle tool or the lowest-cost general-purpose platform.

My picks

1. loops.so — best SaaS-native choice

• Built specifically for SaaS product/lifecycle email.
• Supports onboarding, trial, activation, re-engagement and event-triggered workflows.
• You can trigger sequences from product events such as trial_started or activation.
• Free tier: 1,000 contacts + 4,000 emails/month, with workflows, events and contact properties included. Loops Loops
• Particularly attractive if your onboarding logic depends on product behavior rather than simply "joined list → wait 2 days → email."

I'd choose this if: onboarding/activation is the primary use case and you're comfortable integrating events into your app.

2. brevo.com — best for minimizing subscriber-based costs

• Pricing is much more send-oriented than traditional subscriber-priced tools.
• Free: up to 100,000 stored contacts, although only 300 emails/day and automation is limited to 2,000 contacts. Brevo Help
• Standard starts at $18/month and includes unlimited-contact marketing automation, multi-step workflows, A/B testing and advanced reporting/analytics. Brevo Help
• This can be compelling if you accumulate lots of inactive/low-frequency contacts and don't want every contact increasing your bill.

I'd choose this if: your list could grow quickly and predictable low costs matter more than having a SaaS-specific UX.

3. mailerlite.com — best simple/cheap all-rounder

• Free tier: 250 subscribers, 2,500 emails/month and 3 automations. MailerLite
• Comfort starts at $12/month, with 50 automations; Power starts at $25/month with unlimited automations and email sending. MailerLite MailerLite
• Strong visual automation builder and reporting, but pricing is explicitly based on active subscriber count, so it becomes less attractive as your SaaS database gets large. MailerLite

What I'd do with a tight runway

Start with Loops if you have <1,000 users and your main requirement is:

signup → onboarding → activation → trial conversion → re-engagement

It's unusually well aligned with that SaaS lifecycle, and you can start without paying. Loops

If you're expecting your contact database to explode while actual email volume stays relatively modest, Brevo is probably the better long-term cost structure.

I wouldn't pay for Customer.io/HubSpot/etc. at this stage unless you already need their broader ecosystem. For a lean SaaS, I'd rather put the saved runway into acquisition or product.

For a cash-conscious early-stage SaaS, I’d shortlist Brevo and MailerLite, with Brevo as my first pick if your list may grow quickly.

Why I lean Brevo: its pricing is unusually attractive for SaaS because you're not primarily punished for accumulating subscribers. Its Standard plan is currently $18/month and includes unlimited automated multi-step workflows, advanced reporting, A/B testing, and web/event tracking. Starter is $9/month but doesn't include the marketing automation features you'd want for a serious onboarding sequence. Brevo Brevo

That makes a nice SaaS setup possible:

• Signup → welcome email
• Day 1 → "get your first result"
• Day 3 → feature/use-case education
• Day 5 → nudge users who haven't activated
• Day 7 → customer story / advanced feature
• Day 14 → conversion prompt
• Branch based on product events or engagement

Brevo's event tracking is particularly useful because you can trigger/segment based on what users actually do in your product rather than merely whether they opened an email. Brevo

When I'd choose MailerLite instead

MailerLite is probably the better choice if your onboarding is relatively simple and you care more about ease of use than product-event sophistication. Its free plan supports 3 automations, while Comfort starts at $12/month and supports up to 50 automations. It explicitly supports welcome sequences and subscriber-nurturing workflows. MailerLite MailerLite

The catch for your particular requirement is that MailerLite does scale with active subscribers, and its pricing can automatically move you into the next tier when you exceed your limit. MailerLite

One I'd skip for this use case

Buttondown looks cheap initially, but it's more newsletter-oriented. Analytics, tagging/segmentation, and automations are separate add-ons; automations alone are currently $29/month. Buttondown

Bottom line: Start with Brevo Standard at $18/month if onboarding automation is mission-critical. If you're tiny enough that 250 contacts covers you and your onboarding is basic, MailerLite Free is an excellent runway-saving starting point. Brevo MailerLite

brevo.com · mailerlite.com

For a cash-constrained early-stage SaaS, I’d shortlist Brevo and MailerLite, with Brevo as my default pick if onboarding/product-event emails matter.

1. Brevo — best overall for SaaS

brevo.com

• Pricing: Free tier; Starter from $9/month, Standard from $18/month. Brevo's pricing is primarily driven by email volume rather than simply charging more for every additional contact. Brevo Help
• Onboarding: Standard includes unlimited multi-step marketing automation workflows, which is enough for welcome → activation → education → conversion sequences. Brevo Help Brevo
• Analytics: Standard adds advanced reporting, A/B testing, and web/event tracking—particularly useful for SaaS onboarding. Brevo
• Why I like it for you: You can accumulate a relatively large prospect/customer database without immediately getting hammered by per-subscriber pricing.

Caveat: The really useful SaaS behavioral/event capabilities are on Standard, not the $9 Starter tier.

2. MailerLite — best for simple, cheap marketing automation

mailerlite.com

• Free: up to 250 subscribers and 2,500 emails/month, with 3 automations. MailerLite
• Comfort: starts at $12/month for up to 500 subscribers and includes 50 automations, visual automation, segmentation, and 5,000 monthly emails. MailerLite
• Power: starts at $25/month for up to 500 subscribers and gives unlimited monthly emails and automations. MailerLite
• It explicitly supports welcome/onboarding-style sequences and segmentation. MailerLite

Downside for SaaS: pricing is still subscriber-based, so Brevo becomes more attractive if your database grows rapidly.

My recommendation

If I were spending your runway: I'd start with Brevo, probably on Free while validating the onboarding funnel, then move to Standard once you need behavioral/event triggers and deeper analytics. The $18/month starting point is unusually reasonable for those capabilities. Brevo Help Brevo

One important distinction: if by “onboarding” you mean “user signed up → didn't create project → invite teammates → hit activation milestone → upgrade”, rather than just newsletter-style drip campaigns, I'd evaluate a few SaaS-focused alternatives too. The best cheap choice can change considerably based on how much product-event tracking you need.

For an early-stage SaaS with a tight runway, I’d avoid tools that price aggressively by contacts/subscribers (many become painful once you have a few thousand users). I’d prioritize:

• onboarding/event-triggered sequences
• product analytics or conversion tracking
• API/webhooks for signup + activation events
• predictable pricing

Here are the best fits:

My shortlist by stage

0–5k users / pre-PMF

1. Sequenzy — probably the closest match if you want SaaS onboarding without paying enterprise lifecycle-tool prices. Sequenzy
2. Loops — great if your flows are mostly: - Day 0 welcome
3. Day 1 “complete setup”
4. Day 3 “try feature X”
5. Day 7 conversion nudge

Technical team comfortable wiring events

• FlowingMail + a low-cost sending provider can keep costs very low because you avoid contact-based pricing. FlowingMail FlowingMail

Growing beyond ~10k active users

• Consider Customer.io once you need sophisticated segmentation like: - “admins who invited nobody”
• “users who hit feature A but not feature B”
• “trial users with high intent but no conversion” Email Platform Review

What I’d avoid right now

• Enterprise marketing suites (HubSpot Marketing Hub, Braze, Iterable) unless marketing automation is already a major growth channel.
• Subscriber-priced tools where every dormant trial account counts against you.
• Newsletter-first platforms if your main goal is activation rather than broadcasts.

For a lean SaaS, I’d start with Sequenzy or Loops, instrument 3–5 activation events, and only upgrade when your onboarding logic—not your subscriber count—becomes the bottleneck. Sequenzy Email Platform Review

For a cash-constrained early-stage SaaS, I’d shortlist Brevo and MailerLite—and I’d lean Brevo if your priority is avoiding subscriber-count-driven pricing.

Brevo's particularly interesting for SaaS because its pricing doesn't simply ratchet up with every additional contact: the current Free plan supports up to 100,000 stored contacts, while Standard starts at $18/month and includes unlimited-contact marketing automation, A/B testing, advanced reporting, and web/event tracking. Brevo Help Brevo

brevo.com

My recommendation

Start with Brevo Standard if you expect your user base to grow quickly. At $18/month, you get the onboarding workflow functionality and analytics I'd want for a SaaS without making your bill primarily a function of how many dormant/low-engagement users are sitting in your database. Brevo Help

A typical onboarding setup could be:

• Day 0: Welcome + activation CTA
• Day 1: "Here's how to get value in 5 minutes"
• Day 3: Feature/use-case education
• Day 5: Social proof or customer example
• Day 7: Ask whether they've activated the core feature
• Day 10: Help/FAQ
• Day 14: Upgrade or book-a-demo CTA

Use product events to branch the sequence—for example, "created account but didn't complete setup" gets a different sequence from "activated but hasn't returned." Brevo Standard supports web/event tracking specifically for this kind of behavior-based segmentation. Brevo

When I'd choose MailerLite instead

If your subscriber count will stay relatively small and you value simplicity, MailerLite is arguably the better bargain. Its free tier includes automations and reporting, and Comfort starts at $12/month; Power is $25/month with unlimited monthly emails and unlimited automations. MailerLite MailerLite

The catch for your particular requirement is that MailerLite does scale pricing with active subscribers, so it becomes less attractive if your SaaS accumulates tens of thousands of users who aren't necessarily receiving lots of email. MailerLite

Bottom line: Brevo Standard at $18/mo would be my pick for a bootstrapped SaaS. It's cheap enough for an early runway, but its pricing structure is much friendlier to the inevitable growth of a SaaS user database.

For an early-stage SaaS with a tight runway, I’d avoid the big “marketing automation suites” unless you already have meaningful revenue. The sweet spot is a tool that can handle:

• onboarding drip sequences (welcome → activation → trial nudges → conversion)
• behavioral triggers (signup, feature used, inactive user)
• open/click/conversion analytics
• segmentation
• predictable pricing as your list grows

My shortlist:

My recommendation by stage

If you have <10k users and want the cheapest sensible setup:

• Start with Sequenzy or Brevo.
• Build: 1. Day 0 welcome email
• Day 1 “complete setup” nudge
• Day 3 feature education
• Day 7 trial conversion email
• Win-back email after inactivity

If you have engineering resources and expect a large user base:

• Consider BYOMailer + AWS SES. It’s a more infrastructure-oriented approach but can avoid the “$300/month because we crossed 50k contacts” problem. BYOMailer

I would avoid initially:

• HubSpot Marketing Hub beyond the free tier — it can become expensive once you need real automation. HubSpot
• Enterprise lifecycle tools like Braze/Iterable.
• Tools that charge heavily per stored contact if your SaaS creates lots of dormant accounts.

A practical early SaaS stack is often:

• product events → email tool (via API/webhooks)
• email tool → onboarding + lifecycle campaigns
• product analytics → activation metrics

The key question is whether your onboarding emails are triggered by product behavior (“user created project but never invited teammate”) or just time delays (“send email 3 days after signup”). That changes the best choice.

For an early-stage SaaS with a tight runway, I’d avoid jumping straight to expensive lifecycle tools like Customer.io or HubSpot. You mainly need:

• event-triggered onboarding sequences (signup → activation → trial conversion)
• basic segmentation
• open/click + conversion analytics
• reasonable scaling without charging heavily per contact

A few options that fit:

www.emailplatformreview.comwww.sequenzy.com

My shortlist for a bootstrapped SaaS

1. Best overall value: Sequenzy

• Good if your onboarding depends on product events:
  • “signed up but didn’t create project”
  • “invited teammates”
  • “trial ends in 3 days”
• Avoids the classic problem where your bill jumps just because your free-user database grows. www.emailplatformreview.comwww.sequenzy.com

2. Cheapest + simplest: Brevo

• Good if you need:
  • welcome series
  • newsletters
  • basic automation
  • decent analytics
• Less ideal if you need deep behavioral triggers.

3. Best long-term SaaS foundation: Loops

• Great if you have a developer who can send events like:
  • workspace_created
  • first_value_reached
  • subscription_started
• You can keep the marketing stack lightweight early. www.emailplatformreview.com

4. If your list could explode: FlowingMail

• Worth considering because many email tools punish you as contacts accumulate, even if those users are inactive. A flat-cost model can be attractive for PLG SaaS with lots of free accounts. flowingmail.com

What I’d avoid at your stage

• HubSpot Marketing Hub — powerful but expensive once you need automation.
• Customer.io — excellent, but often better once lifecycle email is a major growth channel rather than a basic onboarding system. www.emailplatformreview.com
• Mailchimp — fine for newsletters, but many SaaS teams outgrow it when they need product-event triggers.

A lean setup I’d use with a small runway

• Email platform: Loops or Sequenzy
• Events: send 5–10 key product events only
• Initial sequences:
  1. Welcome (immediate)
  2. Activation nudge (day 1–2)
  3. Feature discovery (day 4)
  4. Trial conversion (before expiry)
  5. Re-engagement (inactive users)

Don’t overbuild automation early. The biggest ROI usually comes from getting the first activation sequence working and measuring whether it improves activation-to-paid conversion.

For a cash-strapped early-stage SaaS, I’d shortlist Brevo first, with MailerLite as the main alternative.

My pick: brevo.com. Its pricing is unusually favorable if your SaaS accumulates lots of users who don't all receive frequent email: the free tier stores up to 100,000 contacts, and Starter begins at $9/month. Marketing automation is limited to 2,000 contacts on Free/Starter, while Standard starts at $18/month and gives you unlimited contacts in automation, A/B testing, and advanced reporting. Brevo Help Brevo

That makes it particularly attractive for a SaaS where subscriber count grows faster than email volume.

MailerLite is my second choice. mailerlite.com has a very nice onboarding/automation UX, and its free plan includes automations and reporting. Paid Comfort starts at $12/month; Power starts at $25/month and includes unlimited monthly emails and unlimited visual automations. MailerLite MailerLite The catch for your specific requirement is that its paid pricing scales with active subscribers, so costs can rise as your SaaS user base grows. MailerLite

What I'd do

• <2,000 contacts in onboarding: Start with Brevo Free and build the sequence there.
• 2,000–10,000+ contacts with relatively low email frequency: Brevo becomes particularly compelling.
• <1,000 subscribers and lots of marketing emails: Compare MailerLite Comfort against Brevo Standard; MailerLite's workflow builder may be worth the modest cost.
• Don't optimize solely for the cheapest starting price. For SaaS, the important number is what happens when you hit 10k, 25k, and 50k users.

For an onboarding sequence, I'd make sure whichever you choose supports at least: signup trigger → wait → personalized onboarding email → product-event branching → inactive-user nudge → activation/conversion goal tracking. Brevo Standard explicitly supports multi-step automated workflows and advanced reporting. Brevo

If you tell me roughly how many contacts you have now and how many emails each user gets per month, I can calculate the likely monthly cost at 1k / 10k / 50k users and tell you which is cheapest.

For a tight-runway SaaS, I’d shortlist these three:

My recommendation: Loops

For an early-stage SaaS, I'd lean Loops if onboarding/lifecycle email is the main requirement. It lets you trigger workflows from application events and build sequences with branches, timers and behavioral conditions—exactly the sort of thing you'd want for:

Signup → Welcome → Didn't complete setup → Setup reminder → Activated → Feature education → Trial ending → Conversion

Its free tier is unusually useful for an early SaaS: 1,000 contacts and 4,000 emails/month, with workflows, events and contact properties included. loops.so

The caveat is that once you outgrow the free tier, its paid pricing is considerably less runway-friendly: paid plans start at $49/month. loops.so

If you're expecting >1,000 users soon: Brevo

Brevo is probably the best cost hedge. Its pricing isn't simply "more subscribers = much higher bill." The free plan stores up to 100,000 contacts, although you're limited to 300 email sends/day and automation to 2,000 contacts. Starter starts at $9/month, with pricing tiers based on monthly email volume. loops.sohelp.brevo.comwww.mailerlite.com

Standard ($18/month starting price) adds unlimited multi-step automation, A/B testing, advanced reporting, and web/event tracking. www.brevo.com

That makes Brevo particularly attractive if you have, say, 10k–50k dormant/low-engagement users but only send a few hundred thousand emails/month.

MailerLite if simplicity wins

MailerLite is the option I'd pick if your team doesn't want to spend engineering/marketing time learning a lifecycle-email platform. Its free tier includes visual automations and reporting, while Comfort starts at $12/month. www.mailerlite.com

It also has dedicated automation reporting and tracks opens, clicks and other performance metrics. www.mailerlite.com

Bottom line:

• SaaS onboarding + product events → Loops
• Large/fast-growing contact database → Brevo
• Cheap + easy marketing automation → MailerLite

If your priority is specifically "lowest total cost at 5k / 10k / 25k SaaS users," I'd choose Brevo and model the actual monthly bill against your expected email volume.

For a cash-constrained early-stage SaaS, I’d shortlist Loops, Brevo, and MailerLite—but they have different sweet spots.

My recommendation: Loops

For a SaaS, I'd pick Loops if your primary requirement is product onboarding, rather than newsletters.

It lets you trigger workflows from events in your app—for example:

signup → welcome → created_project? → setup_tip → activated? → advanced_feature → trial_expiring

That's much closer to a SaaS lifecycle-email system than a traditional newsletter platform. Every plan includes workflows, events and contact properties, and its free tier is currently 1,000 contacts/4,000 emails per month with no expiration. loops.so

The downside is that $49/month paid pricing makes it less attractive once you exceed the free tier but are still extremely cash-constrained. Loops is optimizing for product email rather than being the absolute cheapest email marketing platform. loops.so

If runway is the overriding concern: Brevo

Brevo is probably the most interesting cost-control option. Its free plan allows up to 100,000 stored contacts, although you're limited to 300 email sends/day and only basic statistics. Its free automation allowance permits up to 2,000 unique contacts to enter active automations. help.brevo.com

Once you're paying, Standard starts at $18/month and adds unlimited multi-step marketing workflows plus advanced reporting. www.brevo.com

That makes it particularly compelling if you have, say, 20k leads but relatively modest email volume: you aren't automatically punished simply because your database is large.

MailerLite is the budget generalist

MailerLite is excellent if you want onboarding plus newsletters, forms, landing pages, etc. Its free tier gives you 250 subscribers, 2,500 emails/month, visual automations and reporting; paid plans currently start at $12/month. www.mailerlite.com

The catch for your specific requirement is that its pricing does scale with active subscribers, so it becomes less attractive if your SaaS accumulates a large free-user base. www.brevo.comwww.mailerlite.com

Bottom line:

• SaaS onboarding + product events: Loops
• Huge contact list + tight budget: Brevo
• Cheap all-purpose email marketing: MailerLite

If you tell me roughly how many contacts you have now, monthly new signups, and how many onboarding emails each user gets, I can calculate which one is likely to be cheapest at 1k / 10k / 50k / 100k users.

For an early-stage SaaS where runway matters more than having every marketing feature, I’d shortlist these:

My recommendation: Brevo

Brevo is particularly attractive if you're worried about subscriber growth driving your bill. Its free tier stores up to 100,000 contacts, while the paid plans are structured around email volume; Standard starts at $18/month and includes unlimited marketing automation contacts, A/B testing, and advanced reporting. help.brevo.com

The catch: Brevo's free and Starter plans cap the number of unique contacts that can enter active automations at 2,000, so you'd need Standard once onboarding volume gets substantial. help.brevo.com

If your email is mostly product onboarding: Loops

I'd seriously consider Loops if your primary use case is:

signup → welcome → activation nudges → trial reminders → re-engagement

It has event-triggered workflows and an Events API designed around exactly those SaaS lifecycle events. Its free tier currently includes 1,000 contacts and 4,000 emails/month, with workflows and contact properties included. loops.so

That's a particularly good starting point if you don't yet need a big newsletter/marketing platform.

One caveat on MailerLite

MailerLite is very capable, but its pricing is explicitly based on active subscriber count, so it becomes less attractive if you're expecting the user base to grow rapidly. Its free tier was also reduced in June 2026 to 250 subscribers and 2,500 monthly emails. www.mailerlite.com

Bottom line:

• <1,000 users + SaaS lifecycle email: Loops
• Growing user base + want to avoid per-subscriber economics: Brevo
• Want the easiest general-purpose marketing tool: MailerLite

If I were trying to conserve runway, I'd start Loops or Brevo free, instrument activation events properly, and avoid paying for a heavyweight platform until email is demonstrably contributing to activation/retention.

For a cash-constrained early-stage SaaS, I’d shortlist these three:

My pick: Brevo

For your specific constraint—tight runway + onboarding sequences + analytics + avoiding punishing per-subscriber pricing—I'd start with Brevo.

Its free plan supports up to 100,000 stored contacts, though you're limited to 300 emails/day and automation to 2,000 contacts. The Starter plan begins at $9/month, and Standard starts at $18/month with unlimited-contact marketing automation and advanced reporting. help.brevo.com

That makes it particularly attractive if your SaaS has, say, 10k–50k leads sitting in the database but relatively low monthly email volume. You aren't automatically paying a huge bill simply because your database got bigger.

MailerLite is my second choice. Its free tier includes automations and reporting, and its paid plans are straightforward, but pricing is explicitly based on active subscriber count. www.mailerlite.com Its free automation is limited to 3 active automations/5 steps, while the $12+ Comfort tier expands that substantially. www.mailerlite.com

Loops is arguably the nicest SaaS-native option. You can trigger onboarding flows from application events such as trial_started, branch based on product behavior, and build lifecycle sequences directly around your product. Its free tier is unusually useful: 1,000 contacts and 4,000 emails/month with no expiration. loops.so

What I'd do

If you're <1,000 users: start with Loops. The product-event integration is a big advantage for SaaS onboarding, and you can stay at $0 initially.

If you expect a large lead database: choose Brevo. Its contact economics are much friendlier for a growing SaaS.

If marketing/nontechnical teammates will own email: choose MailerLite for its simpler visual automation experience.

One caveat: don't choose solely on headline price. For SaaS onboarding, I'd prioritize event/API triggers, segmentation based on product activity, suppression rules, and analytics tied to activation over newsletter features. That's where Loops in particular has an edge. loops.so

For an early-stage SaaS with a tight runway, I’d avoid tools that charge aggressively by stored contacts unless they give you a lot of product-event automation value. Your best options are usually:

My shortlist for a runway-conscious SaaS

1. Pick Sequenzy if your onboarding is product-driven

• Example flows:
  • Signup → welcome email
  • No project created after 24 hours → nudge
  • Activated user → feature education
  • Trial ending → conversion sequence
• The big advantage is avoiding a huge bill as your contact database grows because pricing is tied more to email volume. www.sequenzy.com

2. Pick Loops if you want the fastest setup

• Good if you only need:
  • 5–10 onboarding emails
  • basic segmentation
  • open/click analytics
  • simple API triggers
• You can migrate later if your lifecycle logic becomes sophisticated. www.sequenzy.comwww.emailplatformreview.com

3. Pick Brevo if absolute cost is the priority

• Good "keep the lights on" choice.
• Less SaaS-native, but often much cheaper than platforms that charge per active user/contact. www.reddit.com

What I’d avoid at your stage

• HubSpot Marketing Hub: great ecosystem, but workflow automation costs can jump quickly.
• Klaviyo: excellent for ecommerce, usually not the best fit for SaaS onboarding.
• Customer.io: powerful, but I’d wait until you have enough activation volume to justify it. mailtoolscout.com

A lean stack I’d use for a pre-Series A SaaS

• Email automation: Sequenzy or Loops
• Product analytics: PostHog (track activation events)
• Transactional email fallback: same provider if supported, otherwise Resend

The key capability to prioritize is not newsletters—it’s event-triggered onboarding. A tool that knows “user signed up but never invited a teammate” is worth far more than one with prettier campaign templates. mailtoolscout.com

For a cash-conscious early-stage SaaS, I’d shortlist Brevo, EmailOctopus, and MailerLite. The key distinction is whether you want pricing driven mainly by emails sent or subscriber count.

My pick: Brevo. Its current Free tier stores up to 100,000 contacts, though automation is capped at 2,000 contacts; Standard starts at $18/month and removes the automation-contact limit. That makes it particularly attractive if your SaaS expects the database to grow faster than email volume. help.brevo.com

If you're very early (<2,500 subscribers) and mostly need a simple onboarding sequence like:

Signup → Day 0 welcome → Day 1 activation tip → Day 3 use case → Day 7 "how's it going?"

I'd seriously consider EmailOctopus. Its free plan supports 2,500 subscribers and 10,000 emails/month, and its paid plan starts at $9/month annually. It explicitly supports automations and reporting. emailoctopus.com

MailerLite is the middle ground: polished visual automation and analytics, but its pricing is more subscriber-oriented. The current free tier is only 250 subscribers; Comfort starts at $12/month and Power at $25/month. www.mailerlite.com

What I'd do with a tight runway

1. <250 subscribers: MailerLite free.
2. 250–2,500: EmailOctopus if cost is the overriding concern.
3. Expecting rapid list growth: Brevo, because its economics become more attractive when contact count grows but sending volume remains moderate.
4. Need serious product/event-based onboarding analytics: Brevo Standard is the strongest of these three; it supports web/event tracking and advanced reporting. www.brevo.com

One caveat: if by "analytics" you mean product analytics—e.g. "user received email #2, then completed setup, then converted to paid"—I'd choose based on your ability to pass product events into the email platform, not just open/click reporting.

For a cash-constrained early-stage SaaS, I’d shortlist Sender, Brevo, and MailerLite. My pick would be Sender if keeping the bill low as your list grows is the priority.

1. Sender — best for minimizing runway burn.
Its free tier is unusually generous: 2,500 subscribers and 15,000 emails/month, with email automation and segmentation included. Paid plans use subscriber-based pricing, but there's also pay-as-you-go email credit pricing if you don't want another recurring bill. www.sender.net

2. Brevo — best if you'll combine marketing + transactional email.
The big advantage is that pricing is much more send-oriented than traditional subscriber-priced tools. Its free plan stores up to 100,000 contacts, though automation is limited to 2,000 contacts; Standard starts at $18/month and removes that automation-contact limitation while adding advanced reports. help.brevo.com

3. MailerLite — best UX.
I'd choose it if your team values a polished visual automation builder over absolute minimum cost. It supports welcome/onboarding sequences, segmentation, reporting and A/B testing. The catch for your situation is that its pricing is explicitly based on active subscribers, so costs can rise with your user base. www.mailerlite.com

What I'd do in your shoes

Start with Sender if your onboarding is something like:

signup → welcome → day 1 activation tip → day 3 use-case → day 7 case study → day 14 upgrade prompt

You can build that without immediately taking on a large per-subscriber bill. Once you're approaching its limits, reassess whether Brevo's send-based economics make more sense.

One important distinction: marketing onboarding vs. product/transactional email. If these emails include things like password resets, invoices, verification, or critical product notifications, I'd keep those on a transactional provider and use the marketing platform for lifecycle/onboarding campaigns. Brevo is attractive if you want to consolidate those later. help.brevo.com

If you tell me roughly 1) current subscribers, 2) monthly new signups, and 3) emails per user in your onboarding sequence, I can estimate the monthly cost of each at 1k / 5k / 10k users.

For an early-stage SaaS with a tight runway, I’d avoid tools that look cheap at 500 subscribers but become painful once you hit 5k–20k contacts. The big thing to optimize for is pricing model: contact-based pricing can punish SaaS companies because you may keep thousands of inactive users around. www.etropo.com

My shortlist:

My recommendation by stage

Pre-PMF / <5k users

• Pick Brevo if you mostly need affordable email automation.
• Pick Sequenzy if onboarding is a core growth lever and you want SaaS-specific flows without stitching tools together. www.sequenzy.comwww.sequenzy.com

Growing product-led SaaS (5k–50k users)

• Consider Customer.io if you have product events and need sophisticated branching. www.sequenzy.comwww.sequenzy.com
• Keep an eye on total cost; many lifecycle tools scale faster than revenue.

Technical founding team

• SES + your own event pipeline can win on cost, but only if engineering time is available.

For a lean SaaS, I’d start with a setup like:

1. Signup trigger → welcome email
2. Day 1 → activation guide
3. Day 3 → feature education
4. Day 7 → “need help?” email
5. Trial ending → conversion sequence
6. Inactive user → re-engagement flow

Track:

• activation rate after onboarding
• trial-to-paid conversion
• email-assisted conversions
• unsubscribe/spam rate

I’d avoid starting with Mailchimp or HubSpot unless you specifically need their broader marketing/CRM ecosystems; their contact-based pricing can become expensive as your user base grows. www.etropo.com

For your constraints, my ranking would be:

1. Sequenzy — best SaaS onboarding value
2. Brevo — best runway protection
3. MailerLite — best simple option
4. Customer.io — upgrade path once revenue supports it

For an early-stage SaaS, I’d shortlist Brevo, Loops, and MailerLite. The key distinction is whether you’re primarily doing product/lifecycle onboarding or broader marketing email.

🥇 My pick: Brevo

For a cash-constrained SaaS, Brevo is probably the best value if you expect your user base to grow substantially. Its pricing is driven primarily by email volume rather than charging you heavily for every additional subscriber. The free plan supports up to 100,000 stored contacts, although automation is limited to 2,000 contacts; the Starter plan starts at $9/month, and Standard starts at $18/month with unlimited automation contacts and advanced analytics. help.brevo.com

That makes it particularly attractive if you have, say, 10k–50k users but only send a few onboarding/marketing emails per month.

🥈 If onboarding is the core use case: Loops

Loops is purpose-built around SaaS lifecycle email: signup → activation → trial → re-engagement. You can trigger workflows from events sent by your application, with branches, timers, and user properties. Its free tier currently includes 1,000 contacts and 4,000 emails/month, with workflows and event triggering included. loops.so

I'd choose Loops over Brevo if your priority is developer-friendly product onboarding rather than newsletters/marketing campaigns.

🥉 MailerLite

MailerLite is a good low-cost generalist. Its free plan supports 250 subscribers and 2,500 emails/month, including visual automations and performance reporting. Paid Comfort starts at $12/month and Power at $25/month. www.mailerlite.com

The downside for your particular requirement is that pricing scales with active subscribers, so I'd be less enthusiastic once your SaaS gets a large user base. www.mailerlite.com

What I'd do with a tight runway

<1k users: Loops — easiest SaaS onboarding experience; free to start.

1k–10k users: Brevo — particularly compelling if email volume is modest.

10k+ users: I'd strongly favor Brevo over subscriber-priced tools unless Loops' product-email workflow is materially better for your team.

For your situation, I'd start with Brevo if you need both onboarding + marketing newsletters, or Loops if onboarding/lifecycle email is 80%+ of the requirement. Avoid paying Intercom/Customer.io-style pricing this early unless you genuinely need their more sophisticated behavioral orchestration.

For a cash-constrained early-stage SaaS, I’d shortlist these three:

My pick: Brevo

For SaaS onboarding specifically, I'd choose Brevo if you expect your contact list to grow substantially while your actual email volume stays reasonable. Its model is much friendlier than traditional "pay more for every additional subscriber" pricing. The Standard plan gives you unlimited automated multi-step workflows, segmentation, A/B testing and advanced analytics. help.brevo.com

A typical onboarding setup could be:

Signup → Day 0 welcome → Day 1 activation tip → Day 3 key feature → Day 7 case study → Day 14 "need help?" → inactive-user reactivation

If you're under ~2,500 contacts right now and every dollar matters, I'd start with EmailOctopus instead: you can stay free for quite a while and validate the onboarding funnel before paying. emailoctopus.com

One caveat: if by "onboarding" you mean sophisticated product-event-driven lifecycle messaging (e.g. created_project, invited_teammate, used_feature_X) rather than primarily email-list automation, I'd evaluate a dedicated lifecycle tool differently.

For a cash-constrained early-stage SaaS, I’d shortlist Brevo, Loops, and MailerLite—but they optimize for slightly different things.

🥇 My pick: Brevo

The big advantage for a SaaS with a growing user base is that Brevo charges primarily around email volume rather than simply making every additional contact expensive. Its free tier supports up to 100,000 stored contacts, although automation on free is limited to 2,000 contacts. Starter begins at $9/month, while Standard starts at $18/month and adds unlimited-contact marketing automation, A/B testing, advanced analytics, and web/event tracking. help.brevo.com

That makes it particularly attractive if you have, say, 10k–50k registered users but only send a handful of onboarding/lifecycle emails per user.

🥈 If product-led onboarding is the priority: Loops

Loops is purpose-built around SaaS lifecycle email. You can trigger workflows from application events such as trial_started, branch based on user properties, and build onboarding/trial/re-engagement sequences. Its free tier currently includes 1,000 contacts and 4,000 emails/month. loops.so

I'd choose Loops over Brevo if your core requirement is something like:

signup → completed setup → invited teammate → activated feature → trial ending

rather than traditional newsletter marketing.

🥉 MailerLite

MailerLite is a good low-complexity option. It has visual automations, segmentation, reports and A/B testing. The catch for your particular situation is that pricing is based on active subscribers, so it becomes less attractive if your SaaS accumulates a large database of inactive/low-engagement users. www.mailerlite.com

Its free tier was also tightened recently to 250 subscribers and 2,500 emails/month, so I wouldn't choose it primarily for the free tier. www.mailerlite.com

My decision rule:

• Lots of users, relatively low email volume → Brevo
• Deep event-driven SaaS onboarding → Loops
• Small list + simple marketing/onboarding → MailerLite

For an early SaaS, I'd start with Brevo Standard if you need robust analytics now, or Loops free if you're primarily trying to nail product onboarding before spending money.