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Advanced Mock API Workspace

Everything here runs locally in your browser (localStorage) — nothing you configure is sent to a server. Design an endpoint, simulate real-world conditions, and export it as an OpenAPI file or ready-to-paste client code. New to mocking APIs? Start with the basics in Docs first.

What you can do here

Each feature below is optional and off by default — turn on only what your test needs.

Query & path params

Define paths like /api/users/:id and add query params to test dynamic URLs before a backend exists.

Status codes & errors

Return any status (200–599) or a preset to verify your app's error handling and messaging.

Delays & flaky network

Add delays, random failures, timeouts or offline responses to test spinners and retry logic.

Dynamic response values

Use templates like {{uuid}}, {{now}} and {{query.name}} for realistic ids and timestamps.

Local offline datasets

Seed records, generate from a JSON Schema, or import your own collection — stored in your browser.

OpenAPI import/export

Import a Swagger file to scaffold endpoints, or export your project as OpenAPI to share.

Conditional responses

Match on the request — e.g. header.x-plan=free ⇒ 402 — to simulate empty, paywalled or cancelled states.

Docs, cURL & client code

Turn an endpoint into docs, a cURL command, or client code in JS, TS, Python, Go, Java or C#.

Browser workspace

Design, run, and export local mocks

Create endpoints, simulate auth and failures, keep request history, seed data, and import/export OpenAPI without sending the project anywhere.

GET
Authentication and conditions

Templates support {{now}}, {{uuid}}, {{query.name}}, {{header.x-role}}, {{body.name}}, and {{env.API_URL}}.

Generate fake data from JSON Schema
Generated docs, clients, and assertions
Local console
Run a local request to see response timing, headers, body, and assertion results.