Formhaus Cloud

A form backend for apps built with AI: an agent publishes a form definition and gets a submission endpoint that validates on the server.

Get started · Endpoint reference · Pricing

How it works

1. The agent publishes the form

Connect the remote MCP server and ask for a form. The agent calls publish_form with a form definition.

Add a waitlist form with an email field and publish it.

2. It gets an endpoint, a link and snippets

{
  "form_id": "abc123",
  "endpoint": "https://api.formhaus.dev/f/abc123",
  "hosted_url": "https://f.formhaus.dev/abc123",
  "embed_snippet": "<script src=\"https://f.formhaus.dev/embed.js\" data-form=\"abc123\" async></script>",
  "dashboard_url": "https://app.formhaus.dev/forms/abc123",
  "version": 1,
  "warnings": []
}

3. Submissions are validated on the server

@formhaus/core checks every submission against the published definition. An invalid one gets a 422 with a message per field, and nothing is stored.

{ "error": "invalid", "message": "Some values are invalid. Fix each field in errors and submit again.", "errors": { "email": "Enter a valid email" } }

Put a form on a site

Only the public form id goes into a page. API keys never reach the browser.

Hosted link, for a site-less form, social posts and email:

https://f.formhaus.dev/abc123

Script embed, for any site including Webflow, WordPress, Tilda, Lovable and plain HTML:

<script src="https://f.formhaus.dev/embed.js" data-form="abc123" async></script>

React, for forms that change without a deploy:

import { FormhausForm } from '@formhaus/react/cloud';
import '@formhaus/core/style.css';

export function Waitlist() {
  return <FormhausForm id="abc123" />;
}

POST JSON from any language or your own UI:

curl -X POST https://api.formhaus.dev/f/abc123 \
  -H 'Content-Type: application/json' \
  -d '{"values":{"email":"ada@example.com"},"skippedSteps":[]}'

A stored submission returns 201 with { "id": "...", "values": {...} }. The full contract is in Get an endpoint.

What the owner gets

• Dashboard with a responses table per form.
• CSV export.
• Webhooks signed with a per-form secret, retried with backoff for up to 24 hours.
• Email when a form reaches a response milestone: the 1st, 10th, 100th response and so on.
• REST API with an API key: POST /v1/forms, GET /v1/forms and GET /v1/forms/{id}/submissions, as JSON or CSV.

Agents

Remote MCP server, nothing to install:

claude mcp add --transport http formhaus https://api.formhaus.dev/mcp

Local @formhaus/mcp, which also validates definitions and simulates step paths:

claude mcp add formhaus -- npx -y @formhaus/mcp

Claude Code plugin with the MCP server and form skills:

claude plugin marketplace add ignsm/formhaus && claude plugin install formhaus@formhaus

An agent can publish without an account. Such a form is unclaimed: it accepts 100 submissions and expires after 7 days. The result includes a claim_url, and the owner claims the form by email to keep it. Agents with an API key (fh_live_..., created in the dashboard) can also publish new versions, list forms and read submissions.

Security and data

• Data stays in the EU, in Frankfurt.
• Every submission is validated on the server against the published definition.
• IP addresses are not stored with submissions.
• Backups are encrypted.
• Webhook URLs must be HTTPS and cannot point at private or internal addresses.

See the privacy policy, the terms and the DPA.

Pricing

	Free	Pro	Team
Price	$0	$19/month or $190/year	$49/month or $490/year
Editors (owners included)	1	3	10
Viewers	Unlimited	Unlimited	Unlimited
Forms	3	Unlimited	Unlimited
Submissions per month	100	25,000	100,000
Retention	90 days	Unlimited	Unlimited
CSV export	Yes	Yes	Yes
Roles (owner, editor, viewer)	Yes	Yes	Yes
Webhooks	Yes	Yes	Yes
Email notifications	Yes	Yes	Yes

Get started with the Free plan. Above the limit the endpoint answers 402.

FAQ

How do I add a form to a site built with Lovable or v0?

Ask the agent to publish the form through Formhaus Cloud, then paste the returned <script src="https://f.formhaus.dev/embed.js" data-form="ID" async></script> into the page. In a React or Next.js project, use FormhausForm from @formhaus/react/cloud instead. Both read the latest published definition, so editing the form does not need a redeploy.

Can an AI agent create a form backend?

Yes. The agent calls the publish_form tool on the MCP server at https://api.formhaus.dev/mcp and receives a submission endpoint, a hosted link and an embed snippet in one response. No account is needed for the first publish.

Where is the data stored?

In Frankfurt, Germany, in the EU. Submissions are kept for the retention period of the plan: 90 days on Free, unlimited on Pro and Team. Deleting an account removes its forms and submissions.

What happens to forms created without an account?

They are unclaimed. An unclaimed form accepts up to 100 submissions, expires after 7 days and sends no webhooks or notification emails. Open the claim_url from the publish result and confirm by email to attach the form to your account.

How do I verify webhooks?

Each delivery carries a Formhaus-Signature: t=<unix seconds>,v1=<hex> header, where v1 is HMAC-SHA256 of t + "." + body keyed with the webhook secret of the form. Recompute it, compare in constant time and reject deliveries whose t is more than 5 minutes old. The body is JSON with form_id, submission_id, version, values and created_at. Deliveries are at-least-once, so deduplicate on Formhaus-Submission-Id.

Is the form definition format open source?

Yes. The form definition format, @formhaus/core, the React and Vue renderers and the MCP server are MIT licensed. A definition published to Formhaus Cloud also works with the open-source packages and your own backend.

Can I use my own backend instead?

Yes. Render a definition with FormRenderer and post to your own server, and validate there with validateSubmission from @formhaus/core/server. See Server-side validation.

Which fields does the hosted form support?

The standard field types except file, password, autocomplete, fields with optionsFrom, and unknown custom types. A publish with such a field is rejected with an error that names it.