@formadapter/http

Use any JSON or multipart HTTP endpoint as a FormAdapter submission target.

bun add @formadapter/http

import { createHttpSubmission } from "@formadapter/http";

const submit = createHttpSubmission({ url: "/api/profile" });

<Profile.Form onSubmit={submit} />;

JSON is the default. It sends SubmitContext.input, the prepared schema input before output transforms, so the server can validate and transform again at its trust boundary. The endpoint response is wrapped as a successful shared SubmissionState unless it already returns a well-formed state.

For files or an existing multipart endpoint, send the schema-aware FormData created by the React runtime:

const submit = createHttpSubmission({
  url: "/api/profile",
  body: "form-data",
  init: { credentials: "include" },
});

Do not manually set content-type in FormData mode; fetch must add its boundary. init may also be a per-submit function and can set method/headers. The submit AbortSignal is always forwarded, and a custom fetch implementation is supported.

Structured error states from successful and 4xx responses are preserved. A 4xx string or message is treated as intentional client-safe feedback. Response bodies from 5xx failures and exception messages from network failures are never shown to users; they use errorMessage or a safe fallback instead. Aborts are re-thrown so cancellation keeps working. A failed HTTP status is never treated as success merely because its body resembles a successful state.