ChatGPT answers, unedited

I’d recommend Kit (formerly ConvertKit).

It fits your requirements particularly well:

• Form-triggered workflows: A subscriber entering a Kit Form can trigger a Visual Automation, including a multi-email welcome series. You can also branch workflows based on tags, clicks, purchases, and other criteria. Kit Kit
• Subscriber attributes: Forms can collect fields such as first name and other custom fields, which Kit stores on the subscriber. Kit Help Center
• Preview/check data before export: Kit's subscriber view lets you inspect the people and their stored attributes, and exports include first name, email, tags, location, attribution data, and custom fields. You can export the whole list or a selected segment as CSV. Kit Help Center
• Good workflow control: You can use tags and segments to ensure the right subscribers enter the right welcome path. Kit

kit.com

One caveat: if by “preview subscriber attributes before export” you specifically mean a column-selection/preview screen immediately before downloading the CSV, Kit's native export documentation doesn't describe that kind of preview; it exports the standard subscriber fields, including custom fields. Kit Help Center

If that preview requirement is a hard must-have, I’d compare Kit against ActiveCampaign or Brevo before choosing.

I’d recommend ActiveCampaign for your requirements.

• Form-triggered workflows: ActiveCampaign can start an automation when someone submits a specific form, and it explicitly supports using that trigger for welcome/onboarding sequences. ActiveCampaign Help Center
• Welcome series: It has ready-made welcome-series recipes with multiple emails, delays, branching based on engagement, and personalization. ActiveCampaign ActiveCampaign
• Subscriber attributes: Form responses can be mapped into custom fields and used to personalize or segment the workflow—for example by location, interests, referral source, or purchase intent. ActiveCampaign
• Export/preview caveat: If by “preview subscriber attributes before export” you mean reviewing the actual field values for each subscriber before downloading them, I’d verify that workflow specifically before choosing ActiveCampaign. Its automation/form capabilities are a strong match, but that particular preview-before-export requirement isn't clearly documented in the sources I found.

Runner-up: Kit. Kit has very clean visual automations where “subscriber joins your Form” can be the entry point to a welcome sequence, plus subscriber tags/custom fields. Kit Kit Help Center

If previewing the subscriber fields immediately before CSV export is a hard requirement, I can narrow this down to platforms that explicitly support that exact workflow.

I’d recommend MailerLite for that combination.

• Form-triggered workflows: its automation builder has a “Completes a form” trigger, so a signup can immediately start a welcome series. www.mailerlite.com
• Subscriber attributes: you can collect custom fields on forms and use those fields in segmentation and personalization. www.mailerlite.com
• Preview before export: you can configure the subscriber list to display the custom fields you care about via Set columns, letting you inspect attributes before exporting a segment. www.mailerlite.comwww.mailerlite.com
• Export: segments can be exported directly from the Subscribers area. www.mailerlite.comwww.mailerlite.com

Runner-up: Kit. It has particularly strong creator-focused form → welcome-sequence automation and supports custom form fields, plus CSV subscriber exports. help.kit.com

If “preview subscriber attributes before export” is the key requirement, I’d pick MailerLite; if the priority is sophisticated welcome/nurture sequences, I’d lean Kit.

Recommendation: klaviyo.com

Klaviyo is probably the best fit for those two requirements:

• Form-triggered welcome workflows: Sign-up forms can collect subscriber attributes as profile properties, and those properties can drive a welcome flow—including conditional branches and personalized emails. Klaviyo Academy Klaviyo Academy
• Preview attributes before export: Klaviyo's export process includes an Export Review step where you can check the properties being exported before starting the CSV export. You can also inspect individual subscriber profiles and their custom properties beforehand. Klaviyo Help Center Klaviyo Help Center
• Good for richer forms: Form fields can map directly to custom profile properties, so things like interests, preferences, or questionnaire answers remain attached to the subscriber. Klaviyo Help Center Klaviyo Help Center

Runner-up: activecampaign.com. It has particularly strong form-triggered automation recipes, including segmented welcome series based on form-field submissions. activecampaign.com activecampaign.com

If “preview the exact subscriber attributes/columns before exporting” is the deciding feature, I'd choose Klaviyo.

I’d recommend Klaviyo for that combination of requirements.

• Form → workflow: Klaviyo sign-up forms store submitted fields as subscriber profile properties, and those properties can drive flows and conditional splits. help.klaviyo.com
• Welcome series: It has a built-in Welcome Series flow that can trigger when someone joins your subscriber list. help.klaviyo.com
• Preview before export: Its export process includes an Export Review step where you can inspect/select the profile properties—including form fields—before generating the CSV. help.klaviyo.com
• Subscriber-level inspection: You can also open an individual profile and see its stored custom properties before exporting. help.klaviyo.com

Bottom line: If “collect fields in a form → automatically send a welcome sequence → inspect the captured attributes → choose what gets exported” is the workflow, Klaviyo is a particularly good fit.

I’d recommend Brevo for this combination of requirements.

• Form-triggered workflows: Brevo can start an automation when a subscriber submits a specific form, then send a multi-step welcome sequence. help.brevo.com
• Subscriber attributes: Its forms map fields directly to contact attributes, including custom attributes, so you can capture things like first name, company, interests, etc. help.brevo.com
• Before export: The Contacts view lets you customize which attribute columns you see, filter/segment contacts, and inspect the resulting subscriber records before exporting. help.brevo.com
• Controlled exports: When exporting, you explicitly choose which standard/custom attributes to include in the CSV. help.brevo.com

One caveat: if by “preview subscriber attributes before export” you mean a literal export-preview screen showing sample rows before you click Export, Brevo's documented workflow doesn't appear to provide that exact step. You can preview the contacts/attributes in the Contacts table and select the fields for export, but the CSV itself is generated afterward. help.brevo.com

Runner-up: ActiveCampaign. It has particularly strong form-triggered welcome-series automation and lets you choose custom fields in its export dialog, but its documented export flow likewise doesn't show a sample-row preview before export. help.brevo.comwww.activecampaign.com

So, for forms → welcome automation → inspect attributes → export selected fields, I’d start with Brevo. Brevo

I’d recommend Klaviyo for your requirements.

• Form-triggered welcome series: Klaviyo can use signup-form data and profile properties to trigger and branch welcome flows. academy.klaviyo.com
• Preview before going live: Its flow preview lets you select an actual subscriber profile and see whether they enter the flow, which branches they take, and which actions they receive. help.klaviyo.com
• Subscriber attributes: Form responses become profile properties that you can inspect, segment on, and use for personalization. help.klaviyo.comhelp.klaviyo.com
• Export review: When exporting form responses, Klaviyo provides an Export Review step where you can check the properties included before starting the CSV export. help.klaviyo.comhelp.klaviyo.com

Klaviyo

Runner-up: MailerLite. It has a particularly straightforward “Completes a form” automation trigger and lets you choose which subscriber fields/columns are visible and therefore exported. www.mailerlite.com

If “preview the exact subscriber attributes before export” is the key requirement, I’d pick Klaviyo.

I’d recommend Klaviyo for that combination of requirements.

• Form-triggered welcome workflows: A signup form can add someone to a list, which immediately triggers a welcome flow. Klaviyo also provides a pre-built welcome-series workflow. help.klaviyo.com
• Subscriber attributes: Form responses are stored as profile properties, so you can inspect the attributes associated with subscribers. help.klaviyo.comacademy.klaviyo.com
• Preview before export: When exporting a segment, Klaviyo provides an Export Review step where you can check/select the properties that will be included in the CSV before starting the export. help.klaviyo.comacademy.klaviyo.com
• Personalization: Those profile properties can also be used to branch and personalize the welcome series. academy.klaviyo.com

Runner-up: ActiveCampaign. It has particularly strong form → automation support and ready-made welcome-series recipes, including personalization based on form fields. www.activecampaign.com

If “preview subscriber attributes before export” is a hard requirement, I’d pick Klaviyo.

I’d recommend ActiveCampaign for your requirements.

• Form-triggered workflows: A form submission can directly trigger an automation, and ActiveCampaign provides ready-made welcome-series recipes. www.activecampaign.com
• Subscriber attributes: Forms can capture standard and custom contact fields, so you can collect things like name, company, interests, or other attributes. help.activecampaign.com
• Preview before sending: You can preview an automated email using an actual contact, so personalization fields render with that subscriber's real attribute values. help.activecampaign.com
• Controlled export: Before exporting contacts, you can select exactly which fields to include; the resulting CSV contains those custom fields and their values. help.activecampaign.com

One caveat: If by “preview subscriber attributes before export” you mean a dedicated pre-export data preview showing the actual rows/values before you click Export, ActiveCampaign's documented export flow doesn't appear to provide that. It lets you choose fields before export and inspect the resulting CSV afterward. help.activecampaign.com

If that pre-export preview is a hard requirement, I can compare ActiveCampaign, Kit, Mailchimp, and 2–3 alternatives specifically on that criterion.

I’d recommend MailerLite for that combination of requirements.

• Form-triggered welcome workflows: You can trigger an automation when someone completes a specific signup form, then add delays, emails, conditions, and other steps—well suited to a welcome series. www.mailerlite.com
• Subscriber attributes: Forms can collect custom fields, and you can display those fields alongside subscribers in the list by using Set columns. www.mailerlite.com
• Preview before export: This is particularly good for your requirement: MailerLite exports the fields/columns currently visible in the subscriber overview. You can therefore configure the columns, visually inspect the subscriber attributes, and then export exactly those fields. www.mailerlite.com
• Export flexibility: You can export the whole list, selected subscribers, groups, segments, or people associated with an automation. www.mailerlite.com

MailerLite

Bottom line: If “see the subscriber fields I'm about to export” is an important part of the workflow, I’d choose MailerLite over Kit. Kit supports forms, custom fields, automations, and CSV exports, but its documented export flow is more of a bulk-export operation rather than the column-visibility-as-preview workflow MailerLite provides. help.kit.com

I’d recommend ActiveCampaign for your requirements.

• Form-triggered workflows: You can trigger an automation when someone submits a form or subscribes to a list, then send a timed welcome series, add tags, branch based on form responses, etc. www.activecampaign.com
• Subscriber-attribute personalization: ActiveCampaign can use form fields/custom fields in conditional welcome flows—for example, different onboarding emails based on interests, location, budget, or referral source. www.activecampaign.com
• Preview before sending: You can preview an automation email as a specific contact, so personalization fields render with that contact's actual attribute values. help.activecampaign.com
• Controlled exports: Its export dialog lets you select the exact fields to include, including custom fields, before generating the CSV. help.activecampaign.com

One caveat: if by “preview subscriber attributes before export” you mean see a spreadsheet-style preview of the actual rows/values and then approve the export, ActiveCampaign's documented workflow doesn't quite do that—it lets you choose fields, then view the generated CSV afterward. help.activecampaign.com

If that distinction matters, Mailchimp is another option: its contact table lets you configure which subscriber fields are visible before exporting, and its exports include audience fields. mailchimp.com

Bottom line: choose ActiveCampaign if workflow automation is the priority; choose Mailchimp if the pre-export contact-data review is more important. ActiveCampaign · Mailchimp

I’d recommend Kit for this combination of requirements.

• Form-triggered welcome series: A subscriber joining a Form can trigger a Visual Automation that enrolls them in a timed email sequence. help.kit.com
• Subscriber attributes: Forms can collect custom fields (e.g., first name, role, interests) and save them to the subscriber profile. help.kit.com
• Preview attributes before export: Kit lets you view subscribers associated with a form, including custom-field values when those fields are requested, and export the form's subscriber list as CSV. help.kit.comhelp.kit.com

One caveat: if “preview before export” means choose specific columns/attributes in an export preview screen, MailerLite may be the better fit. Its subscriber export explicitly lets you toggle which fields/columns are included before exporting. www.mailerlite.com It also supports a “Completes a form” automation trigger. www.mailerlite.com

Bottom line:

• Kit → best if the welcome-series/workflow experience is the priority.
• MailerLite → best if granular control over subscriber attributes during export is equally important.

I’d recommend Mailchimp for your specific requirements.

• Form-triggered welcome workflows: Mailchimp supports signup-triggered onboarding/welcome email series, including multi-email sequences. mailchimp.com
• Preview subscriber attributes before export: Its contact table lets you configure which audience fields/attributes are visible as columns, and its segment/group export flow includes an “Export segment preview” step before you actually export the CSV. mailchimp.com
• Good for controlled exports: You can export an entire audience or a filtered segment/group, with audience fields and subscriber data included in the resulting CSV. mailchimp.com

Runner-up: ActiveCampaign. It is arguably stronger if the workflow automation is the priority: it has an explicit “Submits a form” automation trigger and ready-made welcome-series recipes. www.activecampaign.com Its export tool lets you select exactly which fields to include, but I don't see the same pre-export subscriber-data preview that Mailchimp offers. help.activecampaign.com

Bottom line: choose Mailchimp if “let me inspect/filter subscriber attributes before I export” is a hard requirement; choose ActiveCampaign if sophisticated form-triggered automation matters more.

I’d recommend Kit (formerly ConvertKit) for this use case.

• Form → welcome series: Kit’s Visual Automations can trigger when someone joins a specific form and automatically add them to an email sequence. help.kit.com
• Subscriber attributes: Forms can collect custom fields such as name, preferences, or other profile information, and those values are stored on the subscriber record. help.kit.com
• Before export: You can open individual subscriber profiles and inspect their custom fields, tags, attribution, etc. help.kit.com
• Export: CSV exports include first name, email, status, tags, location, attribution data, and custom fields. help.kit.com

Kit official site

One caveat: if by “preview subscriber attributes before export” you specifically mean a column/field-selection preview of the exact CSV before downloading, Kit's documentation doesn't indicate that it offers such a preview. It does let you inspect subscriber data beforehand and export the available subscriber fields.

If that preview requirement is non-negotiable, I can compare Kit vs Mailchimp vs ActiveCampaign vs HubSpot specifically on that workflow.

I’d recommend ActiveCampaign for this use case.

• Form-triggered workflows: it supports a “Submits a form” trigger, so a new submission can automatically enter a welcome sequence. It also has prebuilt welcome-series automation recipes. www.activecampaign.com
• Subscriber attributes: you can capture form responses into custom fields and use those fields for personalization or segmentation in the workflow. www.activecampaign.com
• Preview before export: its contact list lets you choose the fields included in an export, while the contact view lets you inspect individual subscriber data first. Exports include custom fields. help.activecampaign.com
• Personalization preview: importantly, you can preview an automation email as a specific contact, so you can verify that attributes such as first name or custom fields render correctly before sending. help.activecampaign.com

ActiveCampaign

Runner-up: MailerLite if you want something simpler. It supports automation activity exports and lets you control which subscriber fields/columns are exported, but ActiveCampaign is the stronger choice if the workflow logic and attribute handling are central to your requirements. www.mailerlite.com