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mockzilla.org
What it is
Mockzilla turns OpenAPI specifications or plain JSON files into hosted mock APIs for frontend work, integration tests, and demos. It generates responses from OpenAPI schemas and can validate requests against the specification. Users can inject latency or errors at service or endpoint level to exercise retry and fallback behavior. A proxy can forward requests to a real backend while supplying mock responses for routes that backend does not serve. Its GitHub Action creates a mock URL for each pull request, updates it on pushes, and cleans it up when the branch is gone. Mockzilla records request status and timing, and supports replaying individual requests or sets of requests. 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 a GitHub Action and MCP server, with CLI setup instructions for Claude and Gemini. The Free plan is free, but API access is unavailable and request history lasts two hours. Hobby costs $10 a month. Uploaded content must not contain personally identifiable information, real financial data, health records, credentials, or other sensitive data.
Spec sheet
- What it does
- Mockzilla converts OpenAPI specifications or plain JSON files into hosted mock APIs with shareable URLs.Read 15 Oct 2026 · mockzilla.org
- Platforms
- The CLI installation page lists Homebrew for macOS and Linux and separate Windows and Ubuntu/Debian install options.Read 29 Sep 2026 · mockzilla.org
- Integrations
- The site lists a GitHub Action and an MCP server for coding agents; its CLI page gives setup instructions for Claude and Gemini.Read 29 Sep 2026 · mockzilla.org
- Support
- The help documentation says support issues can be opened from a workspace and that contact-form questions receive an email reply.Read 15 Oct 2026 · mockzilla.org
- License
- The Mockzilla engine is released under the MIT license.Read 15 Oct 2026 · github.com
- Access controls
- Simulations support API-key protection, explorer credentials and IP allowlists.Read 15 Oct 2026 · mockzilla.org
- API key roles
- API keys have administrator or editor roles and are managed by organization owners and administrators.Read 15 Oct 2026 · mockzilla.org
- Audit logging
- The settings area includes an audit log showing organizational changes and their actors.Read 15 Oct 2026 · mockzilla.org
- CLI installation
- The CLI is distributed through Homebrew and prebuilt binaries for macOS, Linux and Windows, and runs without an account.Read 15 Oct 2026 · mockzilla.org
- Codegen
- Codegen mode produces typed Go handlers from an OpenAPI specification while keeping the specification in the repository.Read 15 Oct 2026 · mockzilla.org
- Company identity
- GitHub marks the Mockzilla organization as domain-verified for mockzilla.org and lists [email protected] as its contact email.Read 15 Oct 2026 · github.com
- Documentation depth
- The documentation is organized into getting started, simulations, resilient backends, developer tools, settings, billing and help sections.Read 15 Oct 2026 · mockzilla.org
- Error simulation
- Users can set service-wide or endpoint-specific error rates to exercise failure handling.Read 15 Oct 2026 · mockzilla.org
- External platform coverage
- The GitHub organization README lists 24 AWS regions with latency-based routing for hosted simulations.Read 15 Oct 2026 · github.com
- External praise: Go implementation
- A Reddit commenter specifically recommended mockzilla.org for running multiple specifications on one port and identified it as Go-based.Read 15 Oct 2026 · reddit.com
- 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.Read 15 Oct 2026 · reddit.com
- External repository size
- The public GitHub repository showed 110 stars and 6 forks when opened.Read 15 Oct 2026 · github.com
- External validation claim
- The GitHub README reports validation against more than 2,200 OpenAPI specifications and 98,000 endpoints.Read 15 Oct 2026 · github.com
- Fault simulation
- Users can inject latency and errors per service or endpoint to test retry and fallback behavior.Read 29 Sep 2026 · mockzilla.org
- History and replay
- Mockzilla records requests with status and timing and allows users to replay individual requests or sets of requests.Read 29 Sep 2026 · mockzilla.org
- Hosted retention limit
- Request history is a rolling debugging window whose default retention is one hour, with plan-specific retention limits.Read 15 Oct 2026 · mockzilla.org
- Latency simulation
- Latency can be configured for an entire service or individual endpoint.Read 15 Oct 2026 · mockzilla.org
- Local execution
- Simulations can run locally with the CLI, Docker or Docker Compose.Read 15 Oct 2026 · mockzilla.org
- MCP integration
- Mockzilla provides an MCP server that lets Claude Code, Cursor and Gemini CLI launch mock APIs from OpenAPI definitions.Read 15 Oct 2026 · github.com
- Notable news: payment coverage
- A LinkedIn post dated about four weeks before the research date said payment simulations covered 12 providers, including Stripe, PayPal, Adyen and Klarna.Read 15 Oct 2026 · linkedin.com
- Open source and local use
- The CLI is MIT-licensed, runs offline, and the site says it can run on a laptop or in CI; hosted cloud features are opt-in.Read 29 Sep 2026 · mockzilla.org
- Payment backends
- Mockzilla describes payment-provider simulations with decline cases, 3D Secure flows, payment lifecycle operations, and idempotency behavior.Read 29 Sep 2026 · mockzilla.org
- Privacy and security
- The privacy policy says data is protected with TLS in transit and encryption at rest and that simulations run in isolated environments with scoped access.Read 29 Sep 2026 · mockzilla.org
- Protocol limit
- The product currently supports REST and OpenAPI workflows and states that GraphQL and gRPC are not yet supported.Read 15 Oct 2026 · mockzilla.org
- Proxy fallback
- Proxy mode forwards requests to a real upstream and can fall back to generated mocks when the upstream is unavailable.Read 15 Oct 2026 · mockzilla.org
- Public API
- Organization API keys can call the platform API at platform.mockzilla.org/v1 endpoints.Read 15 Oct 2026 · mockzilla.org
- Pull-request environments
- The GitHub Action creates separate simulation URLs for branches and pull requests and removes the pull-request simulation when the PR closes.Read 15 Oct 2026 · mockzilla.org
- Replay recordings
- A real response can be recorded once and replayed for matching requests.Read 15 Oct 2026 · mockzilla.org
- Request validation
- Incoming requests can be validated against the OpenAPI specification.Read 15 Oct 2026 · mockzilla.org
- Schema responses
- The engine generates realistic response data from OpenAPI schemas.Read 15 Oct 2026 · mockzilla.org
- Security reporting
- Each self-hosted build includes component inventories, vulnerability reports, release hashes and SBOM data.Read 15 Oct 2026 · mockzilla.org
- Security: sensitive headers
- Request history masks Authorization, Cookie, Set-Cookie and X-Api-Key values and allows additional mask rules.Read 15 Oct 2026 · mockzilla.org
- Self-hosted storage
- Self-hosted images support memory, Redis, SQLite, PostgreSQL, MySQL/MariaDB, SQL Server, Oracle, CockroachDB, MongoDB and DynamoDB storage drivers.Read 15 Oct 2026 · mockzilla.org
- Self-hosted trial
- Self-hosted provider backends offer a 14-day free trial, limited to one trial per company.Read 15 Oct 2026 · mockzilla.org
- Self-hosting
- Self-hosted backends are supplied as container images for Docker, Compose or Kubernetes and can run inside a private network.Read 15 Oct 2026 · mockzilla.org
- Sensitive data limit
- The terms say uploaded content must not contain personally identifiable information, real financial data, health records, credentials, or other sensitive data.Read 29 Sep 2026 · mockzilla.org
- Service limit
- On the Free plan, API access is unavailable and request history is retained for 2 hours.Read 29 Sep 2026 · mockzilla.org
- Single sign-on
- Organization SSO uses OpenID connections with verified email domains and supports nine identity providers.Read 15 Oct 2026 · mockzilla.org
- Static endpoints
- Static response endpoints can be added for cases that generated data does not cover.Read 15 Oct 2026 · mockzilla.org
- Student access
- Verified students can apply for a free student tier with no card required, subject to manual review that usually takes 1–2 business days.Read 29 Sep 2026 · mockzilla.org
- Who it is for
- The pricing page describes Free for developers evaluating Mockzilla, Hobby for side projects, Starter for solo developers and small teams, and Pro for teams with CI pipelines.Read 29 Sep 2026 · mockzilla.org
Plans and prices
Free Free Free 1K requests/mo · 5 req/s · 1 simulation · 10 MB data transfer Read 29 Sep 2026 · mockzilla.org
Free Free 1K requests/month · 5 requests/second · 1 API key · 2-hour request-history retention · 8 MB stored data · 200 deploys/month · 20 route updates/month · 1 team member Read 15 Oct 2026 · mockzilla.org
Hobby $10 a month $10/mo 100K requests/mo · 10 req/s · 2 simulations · 1 GB data transfer Read 29 Sep 2026 · mockzilla.org
Hobby $10 a month monthly 100K requests/month · 10 requests/second · 2 API keys · 1-day history retention · 600 MB stored data · 600 deploys/month · 60 route updates/month · 2 team members Read 15 Oct 2026 · mockzilla.org
Starter $20 a month monthly 200K requests/month · 20 requests/second · 5 API keys · 3-day history retention · 1.2 GB stored data · 2.5K deploys/month · 200 route updates/month · 5 team members Read 15 Oct 2026 · mockzilla.org
Starter $20 a month $20/mo 200K requests/mo · 20 req/s · 5 simulations · 4 GB data transfer Read 29 Sep 2026 · mockzilla.org
Pro $50 a month $50/mo 400K requests/mo · 40 req/s · 10 simulations · 16 GB data transfer Read 29 Sep 2026 · mockzilla.org
Pro $50 a month monthly 400K requests/month · 40 requests/second · 25 API keys · 7-day history retention · 2.3 GB stored data · 10K deploys/month · 500 route updates/month · 10 team members · 3 admins Read 15 Oct 2026 · mockzilla.org
Enterprise Priced on request Dedicated infrastructure · Custom traffic sizing · Custom domain Read 15 Oct 2026 · mockzilla.org
Strong points and limits
Strong points
- Imports OpenAPI specifications and plain JSON files.
- Can simulate latency and endpoint errors.
- GitHub Action creates mock URLs for pull requests.
- CLI works offline on a laptop or in CI.
Limits
- Free plan has no API access.
- Free request history is retained for two hours.
- Sensitive data must not be uploaded.
Who it suits
Mockzilla suits developers building frontends, integration tests, or demos against mock APIs. Its CLI can suit local or CI workflows, while the hosted features and pull-request URLs are aimed at teams using cloud-based mock environments.
Mockzilla in depth
Read the full write-up
Overview
Mockzilla is a mock-API service and offline CLI for developers building against unfinished or variable HTTP backends. It is a strong fit when schema fidelity, controlled failure cases, and per-PR environments matter; teams handling sensitive data should look elsewhere.
Its mix of hosted workflows and local use is useful, but the Free plan cannot access the API, and uploaded content must not include sensitive information. Those boundaries shape whether Mockzilla is suitable beyond evaluation.
Key features
OpenAPI schemas can drive realistic response generation and request validation, while plain JSON provides a simpler starting point without a formal API contract. This makes Mockzilla useful for frontend work that needs to track an evolving interface, not just serve fixed examples.
Latency and errors can be injected per service or endpoint, giving teams a deliberate way to check retry and fallback behavior. The proxy can forward requests to a real backend and mock routes it does not serve, a practical option while an API is only partly implemented.
The GitHub Action creates a mock URL for each pull request, refreshes it on pushes, and removes it when the branch is gone. That suits teams wanting a separate review environment per change. Request history captures status and timing, and individual requests or sets can be replayed; the Free plan keeps history for just two hours.
Mockzilla also describes payment-provider simulations for declines, 3D Secure flows, lifecycle operations, and idempotency. These cover important payment edge cases, though the prohibition on uploading real financial data means simulations should not use production records.
The MIT-licensed CLI runs offline on a laptop or in CI, with hosted cloud features optional. The site lists a GitHub Action and MCP server, and gives CLI setup instructions for Claude and Gemini. Privacy protections include TLS in transit, encryption at rest, and isolated simulations with scoped access; they do not override the terms' restriction against uploading personally identifiable information, financial data, health records, credentials, or other sensitive content.
Pricing
The Free plan costs nothing, billed Free. It allows 1K requests/mo, 5 req/s, 1 simulation, and 10 MB data transfer. It is positioned for evaluation, but unavailable API access makes it a limited way to judge hosted service use, and its two-hour history retention restricts replay.
Hobby costs $10 a month, billed $10/mo, for 100K requests/mo, 10 req/s, 2 simulations, and 1 GB data transfer. It suits side projects, with modest capacity for concurrent simulations. Starter is $20 a month, billed $20/mo, and raises those limits to 200K requests/mo, 20 req/s, 5 simulations, and 4 GB; that is a better fit for solo developers or small teams with broader needs.
Pro costs $50 a month, billed $50/mo, for 400K requests/mo, 40 req/s, 10 simulations, and 16 GB data transfer. Its larger quotas fit teams with CI pipelines. Enterprise has custom pricing, dedicated infrastructure, an own domain, and capacity sized to traffic. Verified students can apply for a free tier with no card required; manual review usually takes 1–2 business days.
Platforms
Mockzilla supports API, Linux, macOS, self-hosted, web, and Windows use. The CLI's offline mode supports local work and CI, while hosted cloud features are optional. HTTP is the supported protocol.
Who it's for
Choose Mockzilla when a team needs schema-aware mocks, repeatable fault injection, backend proxy fallback, or short-lived pull-request environments. Its offline CLI also suits developers who want local use without depending on hosted features. It is a poor fit for workflows that require uploading real sensitive data, or for Free-plan users who need API access.
Pros and cons
Pro: OpenAPI response generation and request validation help keep mock behavior tied to an API contract.
Pro: Fault injection, proxy fallback, and request replay cover testing situations that static mock responses do not.
Pro: Per-PR URLs and an offline MIT-licensed CLI support both hosted review workflows and local or CI use.
Con: Free has no API access, and its request history lasts only two hours.
Con: The sensitive-content restriction rules out uploading real customer, financial, health, or credential data.
Con: The plan quotas cap request volume, rate, simulations, and transfer, so teams with heavier traffic may need Pro or custom Enterprise capacity.
Alternatives
For a broader comparison, see API Mocking Tools.
Choose Beeceptor if its Individual plan's 15,000 requests per month per endpoint, up to 50 mock rules, private endpoints, and 100 CRUD objects better match a smaller endpoint-based workload; it also offers a free plan and free trial.
Microcks is the alternative to consider for a 100% open-source, community-driven CNCF Incubating project with a free distribution.
Consider Parasoft SOAtest if a paid, quote-based product with a free trial is preferable.
WireMock offers a free plan with 1,000 calls per month, a single user, three mock APIs, and 10 requests per second; that may suit a smaller free workload.
Choose Mockttp if free basic traffic viewing and rewriting, manual breakpoints, and a built-in HTTP client are the main needs.
Mockoon is another freemium option; its team plan costs $10 a month.
MockServer offers a free, open-source self-hosted option without a SaaS account.
WireMock has a free plan with 1,000 calls per month, one user, three mock APIs, and a 10 requests/second limit.
Verdict
Mockzilla is a good choice for developers and teams who want contract-aware HTTP mocks, controlled failures, replay, and pull-request environments, with an offline CLI when hosted features are unnecessary. Its most important drawback is the sensitive-data restriction, followed by Free's lack of API access; choose another tool if either makes the workflow impractical.
Verdict
Mockzilla offers schema-based mocks, fault simulation, request replay, and pull-request environments, with an offline CLI option. Check the Free plan's API restriction and avoid uploading sensitive content.
Where Specifiction places it
- API Mocking Tools#5 of 268.9
