curl -X POST "https://localhost:7000/api/har/upload" \
     -F "[email protected]" \
     -F "environmentName=My Test Environment"

Response:

{
  "environmentId": "a1b2c3d4",
  "message": "HAR file uploaded successfully",
  "mockUrl": "https://localhost:7000/mock/a1b2c3d4"
}

curl -X GET "https://localhost:7000/api/har/environments"

If your HAR contained a request to GET https://api.example.com/users/123, you can now call:

curl -X GET "https://localhost:7000/mock/a1b2c3d4/users/123"

curl -X GET "https://localhost:7000/api/har/environments/a1b2c3d4"

1. Environment Isolation: Each HAR file creates a separate environment with its own mock responses
2. Domain Replacement: Original domains are replaced with the local mock server while preserving paths
3. Fast Lookup: In-memory dictionary for O(1) response lookup by method+path
4. YARP Integration: Uses YARP's IHttpForwarder for efficient request handling
5. Flexible Matching: Supports exact path matching and fallback to path-only (ignoring query params)
6. Production Ready: Comprehensive logging, error handling, and scalable architecture
7. RESTful API: Full CRUD operations for managing HAR environments

1. Create a new .NET 8 Web API project
2. Replace the default files with the code above
3. Run: dotnet run
4. Access Swagger UI at: https://localhost:7000/swagger
5. Upload HAR files via the API and start mocking!

This solution provides a complete, scalable HAR mock server that leverages YARP for efficient request processing and serves immediate mock responses for your testing needs.