Echoes all request headers back as JSON. Header names are uppercased.

{"headers": {"HOST": "testkru.com", "X-CUSTOM": "hello", ...}}

Returns custom response headers.

X-App-Version: 1.0
X-Request-Id: req-testkru-001
Cache-Control: no-cache

Content negotiation. Returns JSON or XML based on Accept header.

{"format": "json", "message": "Response in JSON format"}

<response><format>xml</format><message>Response in XML format</message></response>