Debug CORS errors - reproduce preflight OPTIONS with Origin and Request-Headers ...

{ "method": "GET", "type": "http" }

{ "example": { "body": "Executed against a local server: an OPTIONS preflight with Origin, Access-Control-Request-Method and Request-Headers returning allow headers for one origin and nothing for another, plus guidance on Vary, credentials and why servers cannot fix CORS from the client.", "c": "Self-Hosting & Infra", "id": "cors-preflight-options-request-headers-debug-with-curl", "t": "CORS Errors Debugging: Preflight OPTIONS, Allow-Origin, Allow-Headers and Testing Servers with curl or Python" }, "type": "json" }