Open-source tool for creating mock APIs, with desktop, CLI, and serverless options.
Field note
Mockoon lets you design and run mock REST APIs locally or in the cloud, with a desktop app, CLI, and serverless library.
Capabilities
Tags
Ways to use it
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Node.js / @mockoon/cli
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Product features
Validate how your application handles different API responses and error scenarios.
Prefix all environment routes, e.g. http://localhost:port/myprefix/myroute.
Port number is automatically incremented for each new environment.
POST inserts a new object with an autogenerated id if not provided.
All clients receive identical messages in the same order and intervals.
Trigger HTTP requests from responses.
Command-line interface to run mock servers from data files.
Server responds to each client message; default WebSocket route behavior.
Adds CORS headers to all routes of a mock API with one click.
Automatically answers OPTIONS preflight requests with a 200 status and CORS headers.
Generate multiple endpoints to perform CRUD operations on data buckets, with state persisting between calls.
Provide your own certificate in PKCS12 or PEM format, with passphrase-protected keys and custom-trusted CA certificates.
The id property name used to look up objects can be customized.
Persistent key-value stores linked to responses or used with the data helper.
Broken data file references are repaired on load: missing routes/folders removed, unlisted ones re-added to root.
New environments listen on port 3000 by default.
Cross-platform desktop app to create and run mock APIs.
Optionally remove the API prefix from the path sent to the proxied API.
Disable a route or folder in the app, or via CLI --disable-routes with UUID, name, or wildcard.
Disable TLS at runtime with the --disable-tls flag when using the Mockoon CLI.
Set disableTLS: true when building a MockoonServerless instance to disable TLS.
Docker image that runs the CLI.
Use templating helpers and faker.js to generate dynamic user profiles, product catalogs, and business data.
The main GET route supports filtering, searching, sorting and pagination.
Organize routes into folders and sub-folders with drag-and-drop, for a clearer route hierarchy.
Store and share data between routes in the templating engine.
Basic endpoints to mock any type of API, customizable with headers and body.
Define several responses per route with rules to handle different scenarios.
Each client receives an independent set of streaming messages.
Import OpenAPI specs to design and validate API contracts with stakeholders.
Import and export mock APIs in OpenAPI format.
Import and export OpenAPI specifications.
Start frontend development without waiting for backend APIs to be ready.
Change the port number and API prefix in Environment Settings.
Design and test user workflows with realistic API data before implementation.
Automatically decompress gzip, deflate, brotli or Zstandard proxied response bodies when Content-Encoding is set.
Add custom headers to forwarded requests and to responses received from the target API.
Partial mocking by forwarding unmatched requests to a proxied server.
Query params are not part of route paths; retrieved via queryParam helpers and usable in rules.
Log incoming requests and see how Mockoon responded.
Answer differently based on the index of the requests.
Response rules apply per client in one-to-one streaming; disabled in broadcast mode.
Disable routes or folders from the UI or CLI.
Control route precedence by ordering.
Supports Express 4 and 5 patterns: wildcards, optional params, optional groups and characters.
CRUD routes remain compatible with multiple responses and rules.
Endpoints are created in the order they appear in the list, inside folders or not.
Routes are registered in display order; first match wins, with support for folders and reordering.
Wrapper around the core library for serverless deployments.
Support for one-to-one and broadcast streaming modes.
Dynamic responses using helpers, variables, and Faker.js.
Serve mock APIs over TLS using a custom certificate.
Serve mock APIs over TLS with a self-signed certificate by default, or provide your own PKCS12/PEM certificate and CA.
WebSocket routes automatically use secure wss:// when TLS is configured.
WebSocket routes are served over wss:// when TLS is enabled on the mock server.
Ensure API specifications meet frontend requirements before backend development.
Create WebSocket endpoints with configurable paths like /ws, /chat or /messages.
WebSocket endpoints available alongside HTTP routes.