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Headers Inspector

The /headers endpoint returns the HTTP headers sent by the client. It is useful for debugging proxies, CORS configurations, and request pipelines. Sensitive headers are automatically redacted.

Use Cases

Inspect what headers your client sends to the server, debug reverse proxy configurations, verify CORS headers, or check if authentication headers are being forwarded correctly.

Parameters

ParameterRequiredDescription
filterNoComma-separated list of header names to return. Returns all headers if omitted.

Redacted Headers

The following headers are always returned as [redacted] to prevent sensitive data exposure:

Header
authorization
cookie
set-cookie
proxy-authorization

Response Fields

FieldTypeDescription
countnumberNumber of headers returned
headersobjectKey-value map of request headers (sensitive ones redacted)
ipstringClient IP address
methodstringHTTP method of the request
urlstringFull request URL

Code Examples

curl -X GET \
  "https://api.sylvain.sh/v5/headers"

Try It

Note

This endpoint does not throw errors for invalid filter names — unknown names simply return no matching headers.