Mock HTTP Response Builder

Mock HTTP Response Builder

Construct a structurally correct HTTP response message in seconds. Pick a status code, choose a body type, add headers, and the tool emits a ready-to-paste response string with the status line, headers, and body separated by CRLF — perfect for test fixtures, integration mocks, API documentation, and replaying responses against clients.

Comment utiliser

1. Sélectionnez le HTTP version (defaults to HTTP/1.1) and a status code from the grouped picker — for example 200 OK, 404 Not Found, ou 503 Service Unavailable.
2. (Optional) Override the reason phrase if you need a non-standard text after the status code.
3. Choisissez un body type (Plain Text, JSON, XML, HTML, Form, or None) and type or paste the body.
4. Basculer auto Content-Type, auto Content-Lengthet Date headers to match how your server would respond.
5. Add any extra headers — pick from common ones (Cache-Control, ETag, Set-Cookie, CORS, rate-limit headers) or type a custom name/value pair.
6. Copy the full response, copy just the headers, or download it as a .http file for use in REST clients, fixtures, or replay tools.

Caractéristiques

• Grouped status code picker – Common 1xx through 5xx codes organized by class, each with its standard reason phrase.
• Body type selector – Auto-fills the matching Content-Type (application/json, text/html, application/xml, application/x-www-form-urlencoded, text/plain) so headers and payload stay in sync.
• Auto Content-Length – Counts bytes (not characters) using UTF-8 encoding, matching how real servers compute the value.
• IMF-fixdate Date header – Generates a standards-compliant timestamp (e.g. Sun, 06 Nov 1994 08:49:37 GMT) for the current moment.
• Common response headers – One-click presets for Cache-Control, ETag, Expires, Last-Modified, Location, Server, Set-Cookie, Vary, WWW-Authenticate, Access-Control-Allow-Origin, X-RateLimit, and X-Powered-By.
• En-têtes personnalisés – Add any name/value pair, with live preview of the assembled response.
• Two output views – Full response (status line + headers + blank line + body) and headers-only — copy either, or download the full response as response.http.
• Spec-correct line endings – Uses CRLF (\r\n) between lines, the line terminator mandated by RFC 9112.
• Mises à jour en temps réel – Every change recomputes the output instantly; no submit button needed.
• Fonctionne entièrement dans votre navigateur – No data leaves your machine and no backend is involved.

Cas d'utilisation courants

• Unit and integration test fixtures – Paste the output into a string fixture for requests-mock, nock, MSW, WireMock, or any HTTP recorder.
• API documentation – Show an exact response shape (with headers) in OpenAPI examples or developer docs.
• Client debugging – Reproduce a rare server response (rate limited, partial content, redirect) without standing up a real backend.
• Teaching HTTP – Visualize the on-the-wire format of a response message: status line, headers, blank line, body.
• Manual replay – Pipe the response into nc -l or a similar listener to test how a client reacts.