{"source":"semconv","version":"1.44.0","attribute":{"id":"http.request.header","type":"template[string[]]","stability":"stable","brief":"HTTP request headers, `<key>` being the normalized HTTP Header name (lowercase), the value being the header values.","note":"Instrumentations SHOULD require an explicit configuration of which headers are to be captured.\nIncluding all request headers can be a security risk - explicit configuration helps avoid leaking sensitive information.\n\nThe `User-Agent` header is already captured in the `user_agent.original` attribute.\nUsers MAY explicitly configure instrumentations to capture them even though it is not recommended.\n\nThe attribute value MUST consist of either multiple header values as an array of strings\nor a single-item array containing a possibly comma-concatenated string, depending on the way\nthe HTTP library provides access to headers.\n\nExamples:\n\n- A header `Content-Type: application/json` SHOULD be recorded as the `http.request.header.content-type`\n  attribute with value `[\"application/json\"]`.\n- A header `X-Forwarded-For: 1.2.3.4, 1.2.3.5` SHOULD be recorded as the `http.request.header.x-forwarded-for`\n  attribute with value `[\"1.2.3.4\", \"1.2.3.5\"]` or `[\"1.2.3.4, 1.2.3.5\"]` depending on the HTTP library.","examples":["[\"application/json\"]","[\"1.2.3.4\",\"1.2.3.5\"]"],"namespace":"http","definedIn":"model/http/registry.yaml","usedBy":[{"groupId":"span.http.client","groupType":"span","requirementLevel":"opt_in"},{"groupId":"span.http.server","groupType":"span","requirementLevel":"opt_in"}]},"history":[{"version":"1.30.0","publishedAt":"2025-01-24T19:11:42Z","kind":"first-seen","detail":"Already present at v1.30.0, the oldest release tracked here (stable)."}],"replaces":[]}