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Serverless form to email API

Turn static or frontend-hosted HTML forms into reliable email workflows with spam controls, alias routing, and attachment support.

Use the forms endpoint to receive submissions from HTML forms without hosting a custom email backend.

This is useful for contact forms, intake forms, lead capture pages, and lightweight support workflows where you need delivery reliability more than backend complexity.

Quick start

Submit any HTML form to:

https://api.mailslurp.com/forms

Provide destination metadata using _to or _toAlias, then include normal form fields and optional attachments.

<form action="https://api.mailslurp.com/forms" method="post" enctype="multipart/form-data">
  <input type="hidden" name="_to" value="ops@example.com" />
  <input type="hidden" name="_subject" value="Website contact" />
  <input type="hidden" name="_spamCheck" value="" />
  <input name="_emailAddress" type="email" placeholder="Your email" />
  <textarea name="message" required></textarea>
  <button type="submit">Send</button>
</form>

Routing model

  1. Submission endpoint accepts form fields and files.
  2. Meta parameters control recipient, subject, redirects, and anti-spam behavior.
  3. Delivery target can be direct mailbox (_to) or alias (_toAlias).
  4. Response behavior returns success message or redirect target for frontend UX.

Use aliases for safer public forms

If your form is public, avoid exposing destination mailbox addresses in client markup.

Use _toAlias with a pre-created alias ID so you can rotate destination inboxes without changing frontend code.

See: Email aliases

Anti-spam and abuse controls

  • Add hidden _spamCheck honeypot and keep it empty.
  • Use purpose-scoped aliases per form to isolate abuse.
  • Monitor unexpected volume spikes and rotate aliases when needed.
  • Route high-risk forms to automation rules for moderation workflows.

Form API parameters most teams use

  • _to: destination email address
  • _toAlias: alias ID instead of plain address
  • _subject: email subject
  • _emailAddress: submitter reply address
  • _redirectTo: post-submit redirect
  • _successMessage: custom success text
  • _spamCheck: honeypot field

When to move beyond basic form-to-email

If your workflow needs branching logic, ticket enrichment, or structured extraction, route form messages into automation pipelines:

This keeps your frontend simple while still giving operations teams controlled routing and observability.