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Mock servers

Mock servers let you describe local HTTP/HTTPS endpoints in JSON and get dynamic, rule-based responses without a real backend.

Case-based routing​

Each route can define multiple cases.
The incoming request is matched against these cases (method, path, query, body, etc.), and the first match decides the response. This makes it easy to model different scenarios for the same endpoint.

Jest-style matchers​

Request matching supports a Jest-like syntax, such as:

  • any(Constructor)
  • stringMatching(...)
  • stringContaining(...)

This lets you write expressive conditions (for example “any string containing foo”) directly in your JSON config, without extra code.

Example​

{
  "cases": [
    {
      "request": {
        "query": {
          "name": "{{stringContaining('foo')}}"
        }
      },
      "response": {
        "body": {
          "result": "ok"
        }
      }
    },
    {
      "request": {
        "body": {
          "level": "{{any(Number)}}"
        }
      },
      "response": "@file:../data/welcome.json"
    }
  ]
}

Flexible responses and proxying​

For a matched case you can:

  • Return an inline JSON response.
  • Load the response from a file (for example @file:../data/welcome.json).
  • Or forward the request to another server, acting as a lightweight proxy server.

This combination lets you mix mocked behaviour with real upstream services in a single, versioned workspace.

Proxy Config Example​

{
  "name": "AWS Sam Local",
  "method": "GET",
  "path": "aws",
  "cases": [
    {
      "forward": "https://localhost:3000"
    }
  ]
}