HTTP mocking for development and testing

MockAPI
Configure the response.
Test your application.

MockAPI is an open-source, self-hosted mock API server designed for efficient request handling and a small memory footprint. Configure status codes, headers, and response bodies through the dashboard or a JSON file. Use it to test successful requests, rate limits, server errors, and connection failures. Endpoint changes take effect without a restart.

Get started Read the documentation

MockAPI dashboard with 41 Trailhead Supply example endpoints grouped by API, request statistics, and a populated request log. — **Dashboard overview.** Example endpoints, request statistics, and recent outcomes in the side-by-side workspace. Select the image to open it at full size.

Trailhead Supply endpoint registry with the AI assistant group collapsed and inventory and shipping groups expanded, showing HTTP methods, paths, response codes, attempt counts, editing controls, and cURL copy actions. — **Example endpoints.** This capture expands inventory and shipping while keeping the AI assistant group collapsed. Inventory, reservations, shipping, tracking, rate limiting, server errors, and connection aborts, with controls to test and edit each definition.

Trailhead Supply request log with a 43-request sample, the unexpected-request filter, and recent HTTP 200, 429, and 504 outcomes. — **Request log.** Recent entries from a 43-request sample, with UTC timestamps by default, methods, paths, HTTP outcomes, transport attempts, and response byte counts. Choose local time in Settings if preferred.

Getting started

Run your mock API locally or in a container

Local development

Run locally

Install the stable .NET 11 SDK, then clone and run. No Node.js tooling is needed just to use MockAPI.

git clone https://github.com/simonkurtz-MSFT/MockAPI.git
cd MockAPI

PowerShell 7

.\start.ps1 -Action run-tutorial

Bash

./start.sh --action run-tutorial

The dashboard opens automatically when MockAPI is ready. If your browser does not open, visit localhost:5080/__mockapi/ .

Isolated runtime

Use a container

Run a published stable image without an SDK or source checkout. The same tag supports Linux AMD64 and ARM64.

docker run --rm -p 127.0.0.1:8080:8080 -v mockapi-data:/data simonkurtzmsft/mockapi:1.11.0

Open localhost:8080/__mockapi/ . The named volume preserves configuration across restarts. Use an explicit published version; there is no latest image alias.

Browse published images

To develop container changes from source, build with Docker instead:

PowerShell 7

.\start.ps1 -Action container-build -ContainerEngine docker
.\start.ps1 -Action container-run -ContainerEngine docker

Bash

./start.sh --action container-build --container-engine docker
./start.sh --action container-run --container-engine docker

WSLC, persistence, and platform guide

Make your first request

Open the dashboard and select Load examples .
Press the play button for /inventory/items (Trailhead Supply inventory).
Changes are saved automatically to your configured writable file, volume, or Azure Blob Storage.

Keep administration private and APIs protected. Before sharing a deployment, configure administrative authentication, HTTPS, and API key protection.

Common uses

Mock API examples for development and testing

Develop against an unavailable API

Configure responses for an upstream API that is not yet available. Requests match an exact HTTP method and path, so your application can call the same routes during development.

Explore inventory examples Explore shipping examples Explore AI assistant examples

Exercise retry behavior

Return HTTP 429 with Retry-After, configure server errors, or abort a connection. Check how your client handles these failures without changing the upstream service.

Configure a response

Keep test configuration in source control

Import and export endpoint definitions as JSON. Review configuration changes in source control or automate them through the management API.

Use the management API

Features

A small, hardened container for your mock APIs

Minimal Native AOT image

Ship only the compiled application and its dependencies. The final image contains no .NET SDK, managed runtime, JIT, compiler, or debug symbols.

See measured image and memory results

Hardened by default

Run as a non-root user, disable runtime diagnostics, support a read-only root filesystem, and protect mock calls with an API key by default.

Review security options

Import, save, and export

Import endpoint definitions, save changes to storage, and export requests as Postman, Insomnia, cURL, JMeter, OpenAPI, k6, or HTTP files.

Explore configuration workflows

Live request view

Watch recent matched requests in the dashboard with timestamps, outcomes, status codes, response sizes, and retry attempt counts.

Understand request statistics

APIM Samples integration

Easily connect APIM Samples to your custom mock APIs. Import live OpenAPI definitions into Azure API Management and use MockAPI as the backend for your scenarios.

Connect custom APIs to APIM

Explore MockAPI on GitHub

MockAPI Configure the response. Test your application.