Echoes back the request’s method, headers, and the parsed JSON body.
Expects a JSON request body.

HTTP Method:

• PUT

Request Body:

• Payload: A generic JSON object.

Responses:

• 200 OK: Returns a JSON object containing method, headers, and parsed body.
• 400 Bad Request: If the request body is not valid JSON.

This handler allows testing of how a client handles different HTTP status codes.
It accepts any HTTP method.

Path Parameters:

• code: The HTTP status code to return (e.g., 200, 404, 500).

Responses:

• Returns the status code specified by the code path parameter.
• If an invalid code is provided (e.g., not a number or out of valid range),
  it defaults to 400 Bad Request.

Extracts and returns the User-Agent header value. Useful for testing
what user agent string your client is sending.

HTTP Method:

• GET

Responses:

• 200 OK: Returns a JSON object containing the User-Agent string.

Generates a new random UUID (Universally Unique Identifier) using the v4 algorithm.
Useful for generating unique identifiers for testing purposes.

HTTP Method:

• GET

Responses:

• 200 OK: Returns a JSON object containing the generated UUID.

Decodes the URL-path base64 string and returns a JSON payload with the
decoded content, a UTF-8 validity flag, and the decoded byte length.

Security

Input is capped at MAX_BASE64_INPUT_BYTES (4096 bytes) to prevent
denial-of-service attacks from oversized decode operations.

Path Parameters

• encoded: The base64-encoded string to decode. URL-safe alphabet is
  preferred; padding is optional.

Responses

• 200 OK: JSON object with encoded, decoded, is_utf8, byte_length,
  and timing.duration_ms.
• 400 Bad Request: Invalid base64 input or input exceeds the size limit.