Mock Servers

Bruno can run a mock HTTP server on your machine, backed by a collection’s saved response examples or by an OpenAPI spec. Point any client at http://localhost:<port> and Bruno returns the status, headers, and body your team already defined - no cloud host, no terminal required.

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Why use Mock Servers?

Frontend and integration teams often need a stable API before the real backend is ready. Mock Servers close that gap:

• Use what you already have - saved examples and OpenAPI operations become mock responses with one click.
• Stay local and git-first - mocks live on disk next to the collection, so teammates cloning the repo get the same mocks.
• Point any client at localhost - browsers work out of the box (CORS is on by default).
• Debug mismatches quickly - a live Request Log and helpful 404 payloads show what was tried and which routes are registered.

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What you get

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How it fits Bruno

Mock responses are stored with your collection, not in a hosted service. Closing Bruno stops every running mock; restarting Bruno does not auto-start them - you start each server deliberately so a background port is never claimed silently. The Request Log is in-memory only (most recent 500 entries per server). It is a debugging aid, not an audit log.

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Share feedback

Share your feedback on Mock Servers directly on usebruno GitHub Discussions.

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Next steps

• Create a mock server - create a mock server from a collection or an API spec, then start and use the base URL
• Run a mock server - interface walkthrough, server controls, request log, response examples, and more.
• Create a mock server from a collection - create a mock server from a collection.
• Create a mock server from an API spec - create a mock server from an API spec.