Client Configuration

The generated rivet.ts file exports configureRivet() — call it once at app startup to set the base URL, headers, and other options.

Options

configureRivet({
  baseUrl: "http://localhost:5000",
  headers: () => ({ Authorization: `Bearer ${token}` }),
  fetch: customFetch,
  onError: (err) => { ... },
});

Option	Type	Description
baseUrl	string	Base URL for all API requests
headers	() => Record<string, string> | Promise<Record<string, string>>	Function returning headers to include on every request (supports async)
fetch	typeof fetch	Custom fetch implementation
onError	(err: RivetError) => void	Error interceptor — see Error Handling for details

Custom fetch

The fetch option accepts any typeof fetch — use it for credentials, auth retry, or request deduplication:

const authFetch: typeof fetch = async (input, init) => {
  const res = await fetch(input, { ...init, credentials: "include" });
  if (res.status === 401) {
    await refreshToken();
    return fetch(input, { ...init, credentials: "include" });
  }
  return res;
};

configureRivet({ baseUrl: "...", fetch: authFetch });

Dynamic headers

The headers function is called on every request, so it always has the latest token:

configureRivet({
  baseUrl: "...",
  headers: () => {
    const token = getStoredToken();
    return token ? { Authorization: `Bearer ${token}` } : {};
  },
});

Error interceptor

onError fires before the error is thrown — useful for global error handling like session expiry:

configureRivet({
  baseUrl: "...",
  onError: (err) => {
    if (err.status === 401) {
      onSessionExpired();
    }
    // Re-throw as your own error type
    throw new MyApiError(err.status, err.body);
  },
});

If onError doesn't throw, the original RivetError is thrown. See Error Handling for full semantics including unwrap: false and network error behaviour.