HTTP

HTTP Attributes

This document defines semantic convention attributes in the HTTP namespace.

AttributeTypeDescriptionExamplesStability
http.connection.statestringState of the HTTP connection in the HTTP connection pool.active; idleExperimental
http.request.body.sizeintThe size of the request payload body in bytes. This is the number of bytes transferred excluding headers and is often, but not always, present as the Content-Length header. For requests using transport encoding, this should be the compressed size.3495Experimental
http.request.header.<key>string[]HTTP request headers, <key> being the normalized HTTP Header name (lowercase), the value being the header values. [1]http.request.header.content-type=["application/json"]; http.request.header.x-forwarded-for=["1.2.3.4", "1.2.3.5"]Stable
http.request.methodstringHTTP request method. [2]GET; POST; HEADStable
http.request.method_originalstringOriginal HTTP method sent by the client in the request line.GeT; ACL; fooStable
http.request.resend_countintThe ordinal number of request resending attempt (for any reason, including redirects). [3]3Stable
http.request.sizeintThe total size of the request in bytes. This should be the total number of bytes sent over the wire, including the request line (HTTP/1.1), framing (HTTP/2 and HTTP/3), headers, and request body if any.1437Experimental
http.response.body.sizeintThe size of the response payload body in bytes. This is the number of bytes transferred excluding headers and is often, but not always, present as the Content-Length header. For requests using transport encoding, this should be the compressed size.3495Experimental
http.response.header.<key>string[]HTTP response headers, <key> being the normalized HTTP Header name (lowercase), the value being the header values. [4]http.response.header.content-type=["application/json"]; http.response.header.my-custom-header=["abc", "def"]Stable
http.response.sizeintThe total size of the response in bytes. This should be the total number of bytes sent over the wire, including the status line (HTTP/1.1), framing (HTTP/2 and HTTP/3), headers, and response body and trailers if any.1437Experimental
http.response.status_codeintHTTP response status code.200Stable
http.routestringThe matched route, that is, the path template in the format used by the respective server framework. [5]/users/:userID?; {controller}/{action}/{id?}Stable

[1]: Instrumentations SHOULD require an explicit configuration of which headers are to be captured. Including all request headers can be a security risk - explicit configuration helps avoid leaking sensitive information. The User-Agent header is already captured in the user_agent.original attribute. Users MAY explicitly configure instrumentations to capture them even though it is not recommended. The attribute value MUST consist of either multiple header values as an array of strings or a single-item array containing a possibly comma-concatenated string, depending on the way the HTTP library provides access to headers.

[2]: HTTP request method value SHOULD be “known” to the instrumentation. By default, this convention defines “known” methods as the ones listed in RFC9110 and the PATCH method defined in RFC5789.

If the HTTP request method is not known to instrumentation, it MUST set the http.request.method attribute to _OTHER.

If the HTTP instrumentation could end up converting valid HTTP request methods to _OTHER, then it MUST provide a way to override the list of known HTTP methods. If this override is done via environment variable, then the environment variable MUST be named OTEL_INSTRUMENTATION_HTTP_KNOWN_METHODS and support a comma-separated list of case-sensitive known HTTP methods (this list MUST be a full override of the default known method, it is not a list of known methods in addition to the defaults).

HTTP method names are case-sensitive and http.request.method attribute value MUST match a known HTTP method name exactly. Instrumentations for specific web frameworks that consider HTTP methods to be case insensitive, SHOULD populate a canonical equivalent. Tracing instrumentations that do so, MUST also set http.request.method_original to the original value.

[3]: The resend count SHOULD be updated each time an HTTP request gets resent by the client, regardless of what was the cause of the resending (e.g. redirection, authorization failure, 503 Server Unavailable, network issues, or any other).

[4]: Instrumentations SHOULD require an explicit configuration of which headers are to be captured. Including all response headers can be a security risk - explicit configuration helps avoid leaking sensitive information. Users MAY explicitly configure instrumentations to capture them even though it is not recommended. The attribute value MUST consist of either multiple header values as an array of strings or a single-item array containing a possibly comma-concatenated string, depending on the way the HTTP library provides access to headers.

[5]: MUST NOT be populated when this is not supported by the HTTP server framework as the route attribute should have low-cardinality and the URI path can NOT substitute it. SHOULD include the application root if there is one.

http.connection.state has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

ValueDescriptionStability
activeactive state.Experimental
idleidle state.Experimental

http.request.method has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

ValueDescriptionStability
_OTHERAny HTTP method that the instrumentation has no prior knowledge of.Stable
CONNECTCONNECT method.Stable
DELETEDELETE method.Stable
GETGET method.Stable
HEADHEAD method.Stable
OPTIONSOPTIONS method.Stable
PATCHPATCH method.Stable
POSTPOST method.Stable
PUTPUT method.Stable
TRACETRACE method.Stable

Deprecated HTTP Attributes

Describes deprecated HTTP attributes.

AttributeTypeDescriptionExamplesStability
http.client_ipstringDeprecated, use client.address instead.83.164.160.102Deprecated
Replaced by client.address.
http.flavorstringDeprecated, use network.protocol.name instead.1.0; 1.1; 2.0Deprecated
Replaced by network.protocol.name.
http.hoststringDeprecated, use one of server.address, client.address or http.request.header.host instead, depending on the usage.www.example.orgDeprecated
Replaced by one of server.address, client.address or http.request.header.host, depending on the usage.
http.methodstringDeprecated, use http.request.method instead.GET; POST; HEADDeprecated
Replaced by http.request.method.
http.request_content_lengthintDeprecated, use http.request.header.content-length instead.3495Deprecated
Replaced by http.request.header.content-length.
http.request_content_length_uncompressedintDeprecated, use http.request.body.size instead.5493Deprecated
Replaced by http.request.body.size.
http.response_content_lengthintDeprecated, use http.response.header.content-length instead.3495Deprecated
Replaced by http.response.header.content-length.
http.response_content_length_uncompressedintDeprecated, use http.response.body.size instead.5493Deprecated
Replace by http.response.body.size.
http.schemestringDeprecated, use url.scheme instead.http; httpsDeprecated
Replaced by url.scheme instead.
http.server_namestringDeprecated, use server.address instead.example.comDeprecated
Replaced by server.address.
http.status_codeintDeprecated, use http.response.status_code instead.200Deprecated
Replaced by http.response.status_code.
http.targetstringDeprecated, use url.path and url.query instead./search?q=OpenTelemetry#SemConvDeprecated
Split to url.path and `url.query.
http.urlstringDeprecated, use url.full instead.https://www.foo.bar/search?q=OpenTelemetry#SemConvDeprecated
Replaced by url.full.
http.user_agentstringDeprecated, use user_agent.original instead.CERN-LineMode/2.15 libwww/2.17b3; Mozilla/5.0 (iPhone; CPU iPhone OS 14_7_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.1.2 Mobile/15E148 Safari/604.1Deprecated
Replaced by user_agent.original.

http.flavor has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

ValueDescriptionStability
1.0HTTP/1.0Experimental
1.1HTTP/1.1Experimental
2.0HTTP/2Experimental
3.0HTTP/3Experimental
QUICQUIC protocol.Experimental
SPDYSPDY protocol.Experimental