What happens when you click "Try it out" in Swagger UI?

Clicking "Try it out" switches an operation's documentation from a read-only display into an interactive form: input fields appear for every declared parameter and request body field, pre-filled with any example values from the spec, and an "Execute" button becomes available.

1. Swagger UI collects the values you enter into the generated form fields.
2. It constructs an actual HTTP request — substituting path parameters into the URL template, appending query parameters, setting headers, and serializing the request body — matching exactly what the spec declares for that operation.
3. If a security scheme is configured and you've authorized via the Authorize button, the appropriate credentials (API key header, bearer token, etc.) are automatically attached.
4. The request is sent directly from the browser to the actual API server (the one declared in the spec's servers list, or wherever it's currently deployed).
5. The real response — status code, headers, and body — is displayed directly below, along with the exact curl command equivalent to the request that was sent.

This means "Try it out" only works against a genuinely reachable, running API server; if the documented server isn't actually accessible from wherever Swagger UI is being viewed (a local-only backend, or a server behind a firewall from the browser's location), the feature will fail with a network error even though the documentation itself is perfectly valid.