Request

BackendRequest represents an outbound Node HTTP request observed by the proxy.

WARNING

Request accessors are methods. Use request.method(), request.url(), request.headers(), and request.postDataJSON(), not properties.

Common accessors

Method / property	Type	Description
request.url()	string	Current request URL, including fallback overrides.
request.method()	string	Current HTTP method.
request.headers()	Record<string, string>	Current headers.
request.allHeaders()	Promise<Record<string, string>>	Same header set, async for Playwright parity.
request.headersArray()	Promise<Array<{ name: string; value: string }>>	Headers as name/value pairs.
request.headerValue(name)	Promise<string | null>	Case-insensitive header lookup.
request.postData()	string | null	UTF-8 request body.
request.postDataBuffer()	Buffer | null	Raw request body.
request.postDataJSON()	unknown	Parsed JSON or form data object.
request.clientId	string	Node agent that made the request.

await backendMocks.route("**/charges", async (route, request) => {
  expect(request.method()).toBe("POST");
  expect(await request.headerValue("content-type")).toContain("application/json");
  expect(request.postDataJSON()).toEqual({ amount: 2000 });
  expect(request.clientId).toBe("api-server");

  await route.fulfill({ status: 201, json: { id: "ch_mock" } });
});

Body parsing

postDataJSON() behaves like Playwright:

Body / content type	Result
No body	null
application/x-www-form-urlencoded	Object built from URLSearchParams entries.
Other body	JSON.parse(request.postData()).
Invalid JSON	Throws.

const payload = request.postDataJSON() as { amount: number };

Response links

Method	Type	Description
request.response()	Promise<BackendResponse | null>	Resolves when the request settles, or null for abort/failure.
request.existingResponse()	BackendResponse | null	Immediate response if already available.
request.redirectedFrom()	BackendRequest | null	Previous request in a redirect chain.
request.redirectedTo()	BackendRequest | null	Next request in a redirect chain.
request.failure()	{ errorText: string } | null	Currently returns null for the backend request object.

const response = await request.response();
expect(response?.status()).toBe(200);

Browser-only stubs

These methods exist for Playwright shape compatibility.

Method	Backend behavior
request.resourceType()	Returns "other".
request.frame()	Throws because backend requests have no frame.
request.serviceWorker()	Returns null.
request.isNavigationRequest()	Returns false.
request.timing()	Returns stable placeholder timing values.
request.sizes()	Returns placeholder sizes.

Types

interface BackendRequest {
  url(): string;
  method(): string;
  headers(): Record<string, string>;
  allHeaders(): Promise<Record<string, string>>;
  headersArray(): Promise<Array<{ name: string; value: string }>>;
  headerValue(name: string): Promise<string | null>;
  postData(): string | null;
  postDataBuffer(): Buffer | null;
  postDataJSON(): unknown;
  response(): Promise<BackendResponse | null>;
  existingResponse(): BackendResponse | null;
  readonly clientId: string;
}