Mirage JS

Free#18 of 26 in API Mocking Tools

Mirage JS: A focused open-source library for simulating REST and GraphQL APIs in the browser. Ranked #18 of 26 in API Mocking Tools by our editors (7.3/10); pricing: Open source; best for browser-only frontend API simulations.

7.3/10★★★★☆Editor score

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At a glance

• Editor score
  7.3 / 10
• Pricing
  Open source
• Best for
  Browser-only frontend API simulations
• Paid from
  Free
• Dynamic responses
  Yes
• Facts checked
  20 Sep 2026

• Where it wins

  • Intercepts XMLHttpRequest and fetch requests without changing network code
  • Combines route handlers, an in-memory database, ORM relationships, and serializers
  • Supports generated data, fixtures, and custom responses for REST and GraphQL

• Where it doesn't

  • Limited to web-based browser use
  • No integrations or OpenAPI workflows
  • Requires frontend JavaScript setup rather than a hosted mock-server service

Our verdict on Mirage JS

Mirage JS is an open-source JavaScript library for frontend developers building, testing, or prototyping applications before a backend API is available. It runs alongside frontend code in the browser, intercepting XMLHttpRequest and fetch requests without requiring changes to the application's network code. Its audience is teams that need local API simulations inside web applications, particularly when backend endpoints are still being developed or are not available.

The library's strongest capability is its control over mock behavior. Route handlers define API endpoints, while request matching can use paths, query parameters, and request bodies. An in-memory database, models, and ORM relationships support stateful scenarios, and factories with createList generate mock data. Fixtures load static records, serializers format responses, and custom responses can set status codes, headers, and request bodies. Support for both REST and GraphQL broadens its use across common frontend API patterns.

Mirage JS fits a browser-centered workflow rather than a hosted service or separate mock-server model. Its published positioning supports local deployment and client-side development, but verified platform coverage is limited to the web. There are no integrations or OpenAPI workflows described, so teams looking for connected design-to-mock pipelines, broader platform coverage, or a centrally managed mock server should choose an alternative. Pick Mirage JS when frontend code needs rich, programmable API behavior directly in the browser; avoid it when hosted infrastructure or ecosystem integrations are central requirements.

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Mirage JS pricing

Mirage JS fact sheet

Alternatives to Mirage JS

• BeeceptorA broad API mocking platform with protocol coverage, contract testing, and hosted or self-hosted deployment.9.4
• MockServerA free, open-source choice for teams that need broad, self-hosted API control.9.1
• WireMockA flexible mocking platform spanning hosted, local, CI/CD, Kubernetes, and self-managed use.9.0

See all Mirage JS alternatives →

Featured on iTechGuides

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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Last updated 7 Oct 2026 · How we research and update