ChatGPT answers, unedited

Yes. If tags/custom fields are the key requirement and you want them on a free plan, I’d shortlist these:

Best fit: MailerLite

MailerLite explicitly supports interest groups (tags), custom fields, and segmentation on its free plan. You can tag subscribers by newsletter/topic, then target or exclude those groups when sending campaigns. www.mailerlite.com

For example, you could have:

• newsletter-tech
• newsletter-finance
• newsletter-weekly
• customer
• lead
• Custom field: industry
• Custom field: subscription_source

Its groups can be manually managed, while segments automatically update based on conditions. www.mailerlite.com

Strong alternative: Brevo

Brevo's free plan is $0/month and allows up to 100,000 stored contacts, although sending is limited to 300 emails/day. It supports custom contact attributes—including text, category, multiple-choice, dates, numbers, and booleans—and those attributes can be used for segmentation. help.brevo.com

My pick for managing multiple newsletters: MailerLite, especially if you want a straightforward tag/group model rather than treating every newsletter as a separate list.

Yes. If you need both tags and custom fields on a free plan, I’d look at these first:

• mailerlite.com — best fit for newsletters. It supports interest groups/tags, custom fields, and segmentation. MailerLite MailerLite MailerLite

• Tags: interest groups such as tech, finance, weekly
• Custom fields: e.g. Company, Role, Newsletter_Type
• Segmentation: combine fields/groups into targeted audiences
• Important current free-plan limit: as of June/August 2026, the free plan is limited to 250 active subscribers and 2,500 emails/month. MailerLite
• brevo.com — best if you expect a larger contact database. Its free plan allows up to 100,000 stored contacts and 300 email sends/day, and it supports custom contact attributes plus segmentation. Brevo Help Brevo Help Brevo Help

• Custom fields can be text, date, number, category, multiple-choice, boolean, etc.
• You can segment based on those fields.
• It doesn't use "tags" quite as naturally as MailerLite, although Brevo does support tags as segmentation conditions.

My pick for multiple newsletters: MailerLite if your lists are under 250 active subscribers; Brevo if having a large shared subscriber database is more important.

If you tell me roughly how many subscribers you have across the newsletters (e.g. 500, 5,000, 50,000), I can narrow it down to the best free option.

Yes. MailerLite is probably the best fit if you specifically want tags + custom fields + segmentation on a genuinely free plan.

• MailerLite — Free for up to 250 active subscribers and 2,500 emails/month. The free plan includes interest groups (tags), dynamic segments, and custom fields, so you can segment readers by things like Newsletter A, Newsletter B, Topic: AI, Customer, etc. MailerLite MailerLite MailerLite

mailerlite.com

• Brevo — Also free, with unlimited contacts stored and 300 email sends/day. It supports custom contact attributes and segmentation, making it attractive if your lists are larger. Brevo Help Brevo Help Brevo Help

brevo.com

My pick for multiple newsletters

MailerLite if you have ≤250 active subscribers and want a straightforward tag/group system.

Brevo if the main constraint is subscriber count rather than monthly sending volume.

If you tell me roughly how many subscribers you have across the newsletters (e.g. 500, 5,000, 20,000), I can narrow it down to the best free option.

Yes — MailerLite is probably the best fit for what you described.

• Tags/groups: Its “Interest Groups” function works like tags, and the Free plan includes unlimited interest groups (tags). www.mailerlite.com
• Custom fields: You can create additional subscriber fields such as newsletter_type, industry, role, or source, and use them for personalization/segmentation. www.mailerlite.com
• Segmentation: You can build dynamic segments from tags, custom data, engagement, location, etc. www.mailerlite.com
• Free limit: As of August 2026, the Free plan supports 250 active subscribers and 2,500 emails/month, with 2 user seats. www.mailerlite.comwww.mailerlite.com

MailerLite Free Plan

One caveat: if you're managing multiple newsletters with several hundred+ subscribers each, the 250-subscriber free limit could become restrictive. Brevo has a much larger contact allowance—up to 100,000 contacts on its free plan—but its free sending limit is only 300 emails/day, so it's a different tradeoff. help.brevo.com

If you tell me roughly how many subscribers you have across the newsletters, I can narrow this down to the best 2–3 genuinely free options.

Yes. MailerLite is probably the best fit if you specifically need tags/groups + custom fields + segmentation on a $0 plan.

• MailerLite — Free plan supports interest groups (tags), custom fields, and dynamic segmentation. The catch: the free plan is limited to 250 active subscribers and 2,500 emails/month. www.mailerlite.com
• Brevo — Better if you have a large contact database: its free plan allows up to 100,000 contacts and 300 emails/day. It supports contact attributes/custom fields and segmentation, though some of its newer tag functionality is plan-dependent. help.brevo.com

My pick for multiple newsletters

If you're managing several newsletters and want something like:

Newsletter = Tech
Newsletter = Finance
Interest = AI
Interest = Investing
Subscriber type = Paid

MailerLite is the cleaner choice because its groups/tags, custom fields, and segments are explicitly designed for this kind of organization. www.mailerlite.com

If you tell me roughly how many subscribers you have across the newsletters (e.g. 500, 5k, 50k), I can narrow it down to the best genuinely-free option.

Yes. If tag-based segmentation + custom fields must both be available on the free plan, I’d shortlist these:

My pick: MailerLite

MailerLite is probably the best fit if your priority is operational segmentation rather than just running a publication. Its free plan includes unlimited interest groups (tags) and dynamic segments, and MailerLite explicitly supports custom subscriber fields. www.mailerlite.com

For example, you could have:

• Newsletter: Tech
• Newsletter: Finance
• Interest: AI
• Interest: Startups

plus custom fields such as:

• Company
• Job title
• Industry
• Signup source

Then build segments such as “Finance + interested in AI” without paying.

Important: MailerLite changed its free plan in June 2026; it now caps the free tier at 250 active subscribers and 2,500 monthly emails, so that's the main drawback for managing multiple newsletters. www.mailerlite.com

If you have a larger audience

beehiiv is worth a serious look. It supports both subscriber tags and custom fields, including using custom-field answers to create dynamic segments. www.beehiiv.com

If you tell me roughly how many total subscribers you have and how many separate newsletters, I can narrow this down to the best actually-free option for your setup.

Yes. MailerLite is probably the best fit if you need both tags and custom fields on a free plan. It supports interest groups (effectively tags), custom subscriber fields, and segmentation. www.mailerlite.com

One important catch: as of June 2026, MailerLite's free plan is limited to 250 active subscribers and 2,500 emails/month. www.mailerlite.comhelp.kit.com

Other options:

• Kit — has subscriber tags and segmentation on its free plan; particularly good if these are creator/newsletter businesses. help.kit.com
• Brevo — free plan allows up to 100,000 stored contacts and 300 email sends/day, but its tagging/segmentation model is somewhat different and less newsletter-centric. help.brevo.com
• Buttondown — supports tags and subscriber metadata, but tags are on its Basic paid plan, so it doesn't meet your "tags at no cost" requirement. docs.buttondown.com

My pick: If you manage multiple newsletters and want to keep one subscriber database while using fields/tags to decide which newsletter someone receives, I'd start with MailerLite or Kit. Kit's model is explicitly built around one subscriber list with tags and segments rather than separate lists. help.kit.com

MailerLite · Kit · Brevo

If tag-based segmentation + custom fields must both be free, my top pick is MailerLite.

Best free options

MailerLite is probably the best fit for managing multiple newsletters. Its free plan includes unlimited interest groups (effectively tags), dynamic segments, and custom fields. www.mailerlite.com

For example, you could have:

• newsletter_tech
• newsletter_finance
• newsletter_weekly
• engaged
• customer
• Custom field: company
• Custom field: role
• Custom field: source

Then combine those attributes into segments for each newsletter. www.mailerlite.com

One caveat: MailerLite's current free plan is limited to 250 active subscribers and 2,500 emails per 30 days. www.mailerlite.com

If you have more than 250 subscribers, I'd look at Brevo first: its free plan supports up to 100,000 contacts and 300 emails/day, though its segmentation model is more attribute/criteria-oriented than MailerLite's tag-centric workflow. www.mailerlite.comwww.mailerlite.comhelp.brevo.com

If you tell me roughly how many subscribers you have and how many separate newsletters you're running, I can narrow this down to the best 2–3 options.

Yes. MailerLite is probably the best fit if you specifically need tags + custom fields for newsletter segmentation at $0.

• MailerLite — Free plan supports up to 250 active subscribers and 2,500 emails/month. It includes unlimited interest groups (tags) and segmentation. www.mailerlite.com
• It also supports custom fields (text, number, and date), which you can use for things like newsletter, industry, source, or customer_type. www.mailerlite.com
• For multiple newsletters, you can use interest groups/tags to keep audiences separate and send each newsletter only to the appropriate group. www.mailerlite.comwww.mailerlite.com

Another strong free option: Brevo. Its free plan allows up to 100,000 stored contacts, though you're limited to 300 email sends/day. It supports custom contact attributes and segmentation based on those attributes. help.brevo.com

My pick:

• MailerLite → better if you're primarily managing multiple newsletters and want straightforward tags/groups.
• Brevo → better if you expect a large contact database and don't mind the daily sending limit.

If you tell me roughly how many subscribers you have and how many newsletters you manage, I can narrow it down to the best free option.

Yes. MailerLite is probably the best fit if your priority is tags + custom fields on a genuinely free newsletter plan.

My pick: MailerLite

For managing multiple newsletters, MailerLite gives you:

• Tags/interest groups — e.g. tech, finance, weekly, premium-interest
• Custom fields — e.g. company, role, newsletter_preference
• Dynamic segmentation based on subscriber data and behavior
• The ability to put subscribers into multiple groups simultaneously. www.mailerlite.com
• Its current free plan allows 250 active subscribers and 2,500 emails/month. www.mailerlite.com

Brevo is the stronger alternative if you expect a larger contact database: its free plan allows up to 100,000 stored contacts, with 300 email sends/day, and supports custom attributes and dynamic segments. help.brevo.com

If you tell me roughly how many subscribers you have across the newsletters (e.g. 500, 5k, 50k), I can narrow it down to the best free option.

Yes. MailerLite is probably the best fit for your use case.

• Tags: MailerLite calls them Interest Groups. You can assign multiple groups/tags to a subscriber and use them for targeting. www.mailerlite.com
• Custom fields: You can create your own subscriber fields (e.g. Newsletter, Topic, Role, Company, Interests) and use them for segmentation. www.mailerlite.com
• Segmentation: You can combine fields, tags/groups, engagement, signup source, etc. into dynamic segments. www.mailerlite.com
• Free plan: As of August 2026, the free plan supports these segmentation features, but is limited to 250 active subscribers and 2,500 emails/month. www.mailerlite.com

Important distinction: If you're managing multiple newsletters, I'd structure it as:

Subscriber → Newsletter A tag + Newsletter B tag + Interest tags

rather than maintaining totally separate lists. That lets one subscriber receive different newsletters without duplicating contacts.

Brevo is another strong free option: its free plan supports up to 100,000 stored contacts, custom contact attributes, and segmentation, but its free sending limit is only 300 emails/day. help.brevo.com

My pick: MailerLite if tags/custom fields and newsletter segmentation are the priority; Brevo if having a large contact database is more important.

MailerLite 

Yes. MailerLite is probably the best fit if you need tags + custom fields + segmentation on a free plan.

My pick: MailerLite. Its free plan explicitly includes unlimited interest groups (essentially tags) and unlimited dynamic segments, and you can use custom fields to refine those segments. www.mailerlite.com

One important catch: MailerLite reduced its free audience limit to 250 active subscribers in June 2026, so it's excellent for small newsletters but less attractive if you have several lists that collectively exceed that size. www.mailerlite.com

If you have multiple newsletters and want one subscriber database with lots of tags, I'd look particularly closely at Sender: its free tier allows 2,500 subscribers and 15,000 emails/month, with segmentation and automation included. www.sender.net

MailerLite · Sender · Brevo

If you tell me roughly how many subscribers you have across the newsletters (e.g. 500, 5,000, 20,000), I can narrow it down to the best genuinely-free option.

Yes. If your priority is tags + custom fields + segmentation on a genuinely free plan, I’d look at these two first:

🥇 My pick: MailerLite

For multiple newsletters, MailerLite is probably the cleaner fit. Its free tier includes unlimited interest groups (tags) and dynamic segments, and you can create custom subscriber fields. www.mailerlite.com

For example, you could have:

• newsletter_tech
• newsletter_finance
• newsletter_weekly
• interested_ai
• customer
• Custom field: signup_source
• Custom field: company_size

You can then combine those fields/tags into segments and target individual newsletters appropriately. www.mailerlite.com

Important catch: MailerLite's free plan currently caps you at 250 active subscribers, despite allowing 2,500 emails/month. www.mailerlite.com

If you have a large contact database: Brevo

Brevo is interesting because its free plan allows up to 100,000 stored contacts and supports custom contact attributes, including text, number, date, category, multiple-choice, and boolean fields. help.brevo.com

The tradeoff is the 300 emails/day sending limit, so it's much more attractive if you need to store and segment lots of contacts than if you're sending high-volume newsletters. help.brevo.com

Bottom line:

• ≤250 subscribers + want straightforward newsletter tagging: MailerLite
• Thousands of contacts + custom-field-heavy segmentation: Brevo
• Multiple separate newsletters with overlapping subscribers: I'd lean MailerLite if you're under its subscriber limit.

Yes. For tag-based newsletter segmentation at $0, I’d shortlist these:

My pick for your use case: Kit. Its free Newsletter plan explicitly includes audience tagging and segmentation, unlimited broadcasts, and one basic automation for up to 1,000 subscribers. kit.com

If by “custom fields” you mean fields like:

• Newsletter = Tech
• Newsletter = Finance
• Role = Founder
• Interest = AI
• Source = Newsletter A

then MailerLite is particularly flexible: its custom fields can hold additional subscriber information, and its free plan includes unlimited interest groups (tags) and dynamic segments. www.mailerlite.com

One important current wrinkle: MailerLite's free tier was reduced to 250 active subscribers and 2,500 monthly emails in June/August 2026, so Kit is considerably more attractive if your lists are growing. www.mailerlite.com

Bottom line:

• Multiple newsletters + tagging → Kit
• Complex custom subscriber data → MailerLite
• Huge contact database → Brevo

If you tell me roughly how many subscribers you have across the newsletters and how many emails/month you send, I can narrow it down to the best free option.