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A form is only the beginning.

Every page puts Postbag beside one service, on the same evidence — the vendor's own sources, a date on every fact.

Last updated

A clear route, not a score

Choose for the form you have now. Keep an eye on the one you will have later.

Most form backends can notify one inbox. The differences show up when a message must stay safe, reach a real system, move with your site, or be wired up by an agent while you're doing something better with your afternoon.

The comparison desk

Six familiar places to start.

Read the one closest to your current setup. The tables keep the details plain, so you can make the call without decoding our marketing first.

  1. Postbag and Formspree Formspree is a good fit for one site and one inbox. Postbag gives your forms more places to go. Open comparison
  2. Postbag and Formspark Formspark is a tidy, one-time-price choice for simple forms. Postbag is for forms you want to keep close. Open comparison
  3. Postbag and Getform (now Forminit) Forminit is made for AI-built frontends. Postbag is made for the agent doing the building. Open comparison
  4. Postbag and Basin Basin is a mature lead-capture platform. Postbag gives your agent the full form setup from the start. Open comparison
  5. Postbag and Web3Forms Web3Forms is a generous free email relay. Postbag is for forms you want to keep track of. Open comparison
  6. Postbag and Netlify Forms Netlify Forms is convenient when every site is on Netlify. Postbag stays with you when a site moves. Open comparison

How to read this

The best choice is usually hiding in the second question.

For one site: start with price, uploads and captcha options. They are the practical constraints.

For several sites or a partner integration: look at durable storage, webhook signing, retries and whether different Forms can arrive in one shape.

For agent-built sites: ask whether the backend can be created and tested without a human clicking around. Postbag was built around that question.

Questions, answered

What is the best form backend for static sites?
It depends on what you need after the email. For one site and one inbox most services work. If you run several sites, need a durable record of every submission and delivery, want webhook signing for a CRM, want to self-host, or want an AI agent to set it up, Postbag is built for exactly that.
Which form backends offer a free tier?
All of the ones compared here do. As of August 2026: Postbag 1,000 submissions/month across 5 forms; Formspree 50; Formspark 250 (one-time, 10 forms); Forminit 100 (1 form); Basin 50 (1 form); Web3Forms 250; Netlify Forms 100 on legacy plans. Check each vendor's page for current numbers.
Which form backends sign their webhooks?
Postbag (Postbag-Signature, HMAC-SHA256), Formspree (Formspree-Signature) and Basin (X-Basin-Signature) do; Netlify uses JWS when a secret is set. Formspark's documentation says it does not currently sign webhooks.
Which form backend can I self-host?
Of the services compared here, only Postbag is designed to self-host: one Docker image plus Postgres, the same image as the hosted product.

Give the form job to your agent.

It can build, wire and test the form before you even sign up. Claim it when it's worth keeping.

Create a form Read the quickstart