WireMock Runner: API Simulation Anywhere You Build

Uri Maoz

Co-Founder and CEO

November 6, 2025

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If you’ve ever tried to simulate APIs -- either internal or third party -- in a large or regulated organization, you know it can get tricky. The APIs you need to simulate often sit behind firewalls or strict network controls that make cloud-only simulation less practical, or limit how readily you can access APIs to keep the mocks current. Developers working locally just want fast feedback loops -- not to wait on remote round-trips or juggle multiple tools to test a workflow.

Today we're introducing WireMock Runner, a containerized service that runs mock APIs wherever you need them while keeping management in WireMock Cloud. Runner connects to Cloud for configuration and collaboration, but executes the simulated API traffic in your own infrastructure - on your laptop, in CI/CD, or inside your private clusters - enabling hybrid workflows that support the way software is developed and tested today.

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Local-first development is a major draw for developers currently using the open source WireMock library. WireMock Runner extends this experience with the full functionality of WireMock Cloud - collaboration, shared mocks, advanced simulation capabilities such as stateful mocking, support for gRPC and GraphQL, and all the enterprise features make WireMock Cloud a popular choice at banks, healthcare organizations, and Fortune 500 companies.

When You Should Use WireMock Runner

To simulate APIs behind firewalls: Internal microservices and private APIs can't reach cloud mocking services. Runner executes inside your network while keeping management in Cloud.
For fast local feedback: Simulate APIs directly on your laptop to eliminate network latency and stay productive offline.
In your CI/CD pipelines: Call simulated APIs in CI environments that work inside of local networks.
In Git-based workflows: Store mock specifications in Git alongside your application code. Runner's file-based format fits naturally into GitOps workflows.
Security and compliance: Process all mock traffic locally when policies prohibit sending data to external services. Only metadata syncs to Cloud.

From “Cloud or Local” to “Cloud and Local”

Before WireMock Runner, teams often had to choose between the control of local mocking and the convenience of a managed cloud service. Enterprise users needed to simulate APIs that never leave a secure network; developers wanted offline speed and no context switching. Now both get what they need. You can record API traffic on your laptop, push it to WireMock Cloud for sharing, and then pull it back into your own infrastructure -- all in one continuous workflow.

That flexibility also makes a big difference in microservice environments, where internal APIs talk to each other constantly. To test those interactions properly, your simulations need to happen inside the same network topology as your production services. WireMock Runner makes that possible: you can spin up mocks in-cluster to reproduce exactly how those internal APIs communicate, without punching holes through your firewall or relying on external connectivity.

Built for Real-World Developer Workflows

WireMock Runner fits naturally into how teams already build. It’s fully configuration-as-code, integrates cleanly into Git and CI/CD, and doesn’t require an internet connection once running. That means developers can stay focused -- no cloud dependency, no tool-hopping. It’s the same principle that’s powered WireMock from the beginning: give developers autonomy and instant feedback, whether they’re on a plane, behind a firewall, or in a test pipeline.

And for teams building AI-powered applications, WireMock Runner adds a new level of reliability. You can record and replay API interactions -- even calls to LLM or inference APIs -- locally and safely, so your dev and test loops stay fast without burning tokens or relying on an external service’s uptime.

A Smoother Path from OSS to Cloud

If you’ve been using WireMock OSS, WireMock Runner makes the transition easier than ever. You can now access all of the advanced capabilities of WireMock Cloud’s enterprise edition, while staying fully secure and compliant behind your own network, and maintaining the local-first development and YAML based configuration you’re already using.