# Submissions and connectors

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`Form0Form` supplies a default submission handler when the caller does not provide `onSubmit`. The
handler creates or accepts a structured form0 record and logs it for development.

When `devServer.submitToConnector` is `true`, it also calls two local endpoints:

1. `POST /api/create-record` when the renderer has not already produced a complete structured record.
2. `POST /api/submit-record` to send that record to connectors managed by form0-cli.

The Vite proxy forwards `/api` to the CLI development server. Start both processes with:

```bash
form0 serve --app
```

Use [CLI connector management](/cli/connector-management) to install, configure, test, and inspect a
connector. Use [Choosing a connector](/connectors/choose) to compare PostgreSQL and SQLite.

## Supply application submission behavior

Pass `onSubmit` to `Form0Form` to replace the default handler. Set
`useDefaultSubmitHandler={false}` if the form should render without either submission path.

For the complete callback record and metadata contract, see
[Values, snapshots, and submission](/bindings/react/values-snapshots-submission).

> [!WARNING]
> The CLI endpoints and Vite proxy are local-development helpers, not a production submission API.
> A deployed application needs a trusted server boundary with authentication, authorization,
> validation, rate limiting, and appropriate storage controls. Never ship database credentials to
> browser code.

Only use schemas from trusted authors. Schema expressions execute within the documented
[form0-core trust boundary](/core/security).