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Mockzilla
What it is
Mockzilla creates mock APIs from OpenAPI specifications or plain JSON files for frontend development, integration tests, and demos. It can generate responses from schemas and check requests against an OpenAPI specification. Developers can add latency and errors at service or endpoint level to exercise retry and fallback handling. A proxy can send requests to a real backend while supplying mock responses for routes the backend does not cover. Its GitHub Action creates a mock URL for each pull request, updates it when new pushes arrive, and removes it after the branch is deleted. Mockzilla records request status and timing and supports replay of individual requests or groups. The CLI is MIT-licensed, works offline, and can run on a laptop or in CI; hosted cloud features are optional. The site also lists an MCP server and payment-provider simulations. Free costs nothing; Hobby costs $10 a month, and paid plans also include Starter at $20 a month and Pro at $50 a month. Uploaded content must not include sensitive data.
For and against
For
- Builds mocks from OpenAPI or JSON.
- Can validate requests and simulate latency or errors.
- Pull requests get automatically managed mock URLs.
- Offline CLI can run on laptops or in CI.
- Free plan is available.
Against
- Free plan does not include API access.
- Free request history lasts 2 hours.
- Uploaded content must not contain sensitive data.
The verdict
Mockzilla offers schema-based mocking, fault simulation, backend proxying, and request replay, with both local CLI use and hosted features. The Free plan has no API access and short history retention, while Hobby is $10 a month.
Who it suits
Mockzilla suits developers building frontends, integration tests, or demos who need configurable mock responses. Its pull-request environments and CI-capable CLI are relevant to teams using those workflows.
Plans and prices
Free
1K requests/month · 5 requests/second · 1 API key · 2-hour request-history retention
Read 15 Oct 2026 · mockzilla.org
Hobby
100K requests/month · 10 requests/second · 2 API keys · 1-day history retention
Read 15 Oct 2026 · mockzilla.org
Starter
200K requests/month · 20 requests/second · 5 API keys · 3-day history retention
Read 15 Oct 2026 · mockzilla.org
Pro
400K requests/month · 40 requests/second · 25 API keys · 7-day history retention
Read 15 Oct 2026 · mockzilla.org
Enterprise
Dedicated infrastructure · Custom traffic sizing · Custom domain
Read 15 Oct 2026 · mockzilla.org
On the record
- Access controls
- Simulations support API-key protection, explorer credentials and IP allowlists.mockzilla.org · read 15 Oct 2026
- API key roles
- API keys have administrator or editor roles and are managed by organization owners and administrators.mockzilla.org · read 15 Oct 2026
- Audit logging
- The settings area includes an audit log showing organizational changes and their actors.mockzilla.org · read 15 Oct 2026
- CLI installation
- The CLI is distributed through Homebrew and prebuilt binaries for macOS, Linux and Windows, and runs without an account.mockzilla.org · read 15 Oct 2026
- Codegen
- Codegen mode produces typed Go handlers from an OpenAPI specification while keeping the specification in the repository.mockzilla.org · read 15 Oct 2026
- Company identity
- GitHub marks the Mockzilla organization as domain-verified for mockzilla.org and lists [email protected] as its contact email.github.com · read 15 Oct 2026
- Documentation depth
- The documentation is organized into getting started, simulations, resilient backends, developer tools, settings, billing and help sections.mockzilla.org · read 15 Oct 2026
- Error simulation
- Users can set service-wide or endpoint-specific error rates to exercise failure handling.mockzilla.org · read 15 Oct 2026
- External platform coverage
- The GitHub organization README lists 24 AWS regions with latency-based routing for hosted simulations.github.com · read 15 Oct 2026
- External praise: Go implementation
- A Reddit commenter specifically recommended mockzilla.org for running multiple specifications on one port and identified it as Go-based.reddit.com · read 15 Oct 2026
- External praise: multi-service use
- A Reddit commenter said Mockzilla can run multiple API specifications on one port with URL prefixes and CI support without extra setup.reddit.com · read 15 Oct 2026
- External repository size
- The public GitHub repository showed 110 stars and 6 forks when opened.github.com · read 15 Oct 2026
- External validation claim
- The GitHub README reports validation against more than 2,200 OpenAPI specifications and 98,000 endpoints.github.com · read 15 Oct 2026
- Fault simulation
- Users can inject latency and errors per service or endpoint to test retry and fallback behavior.mockzilla.org · read 29 Sep 2026
- History and replay
- Mockzilla records requests with status and timing and allows users to replay individual requests or sets of requests.mockzilla.org · read 29 Sep 2026
- Hosted retention limit
- Request history is a rolling debugging window whose default retention is one hour, with plan-specific retention limits.mockzilla.org · read 15 Oct 2026
- Integrations
- The site lists a GitHub Action and an MCP server for coding agents; its CLI page gives setup instructions for Claude and Gemini.mockzilla.org · read 29 Sep 2026
- Latency simulation
- Latency can be configured for an entire service or individual endpoint.mockzilla.org · read 15 Oct 2026
