A form backend is the server that sits behind an HTML form and does everything that has to happen after someone clicks submit: receive the POST, validate the fields, filter spam, store the submission, notify you, and route the data onward. A hosted form backend provides this as a service - you point your form's action attribute at an endpoint URL and the backend handles the rest, with no server-side code on your own site.
This pattern is what makes contact and signup forms possible on static sites, Jamstack builds, and frontend frameworks that have no server of their own. Instead of standing up a backend or a serverless function just to catch a form, you delegate the whole intake workflow - spam protection, file uploads, notifications, webhooks, and storage - to the form backend.
The forms pillar guide covers what makes a form convert and stay secure end to end, and the form backend product page shows the hosted version in practice.
Related terms
Form endpoint
The unique URL that an HTML form posts to, where submissions are received and processed by a form backend.
Jamstack form
A form on a Jamstack (statically generated, JavaScript-enhanced) site that posts to a hosted form backend instead of a server of its own.
Webhook
An automated HTTP POST that a service sends to a URL you control whenever an event happens, so your systems react in near real time without polling.
Honeypot field
A hidden form field that humans never see and never fill, used to catch automated bots that fill in every field.
Read the full guide