HTTP

HTTP Attributes

Attribute	Type	Description	Examples	Stability
http.connection.state	string	State of the HTTP connection in the HTTP connection pool.	active; idle
http.request.body.size	int	The 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.	3495
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"]
http.request.method	string	HTTP request method. [2]	GET; POST; HEAD
http.request.method_original	string	Original HTTP method sent by the client in the request line.	GeT; ACL; foo
http.request.resend_count	int	The ordinal number of request resending attempt (for any reason, including redirects). [3]	3
http.request.size	int	The 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.	1437
http.response.body.size	int	The 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.	3495
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"]
http.response.size	int	The 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.	1437
http.response.status_code	int	HTTP response status code.	200
http.route	string	The matched route, that is, the path template in the format used by the respective server framework. [5]	/users/:userID?; {controller}/{action}/{id?}

[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.

Value	Description	Stability
active	active state.
idle	idle state.

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.

Value	Description	Stability
CONNECT	CONNECT method.
DELETE	DELETE method.
GET	GET method.
HEAD	HEAD method.
OPTIONS	OPTIONS method.
PATCH	PATCH method.
POST	POST method.
PUT	PUT method.
TRACE	TRACE method.
_OTHER	Any HTTP method that the instrumentation has no prior knowledge of.

Deprecated HTTP Attributes

Attribute	Type	Description	Examples	Stability
http.flavor	string	Deprecated, use network.protocol.name instead.	1.0	Replaced by network.protocol.name.
http.method	string	Deprecated, use http.request.method instead.	GET; POST; HEAD	Replaced by http.request.method.
http.request_content_length	int	Deprecated, use http.request.header.content-length instead.	3495	Replaced by http.request.header.content-length.
http.response_content_length	int	Deprecated, use http.response.header.content-length instead.	3495	Replaced by http.response.header.content-length.
http.scheme	string	Deprecated, use url.scheme instead.	http; https	Replaced by url.scheme instead.
http.status_code	int	Deprecated, use http.response.status_code instead.	200	Replaced by http.response.status_code.
http.target	string	Deprecated, use url.path and url.query instead.	/search?q=OpenTelemetry#SemConv	Split to url.path and `url.query.
http.url	string	Deprecated, use url.full instead.	https://www.foo.bar/search?q=OpenTelemetry#SemConv	Replaced by url.full.
http.user_agent	string	Deprecated, 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/604.1	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.

Value	Description	Stability
1.0	HTTP/1.0
1.1	HTTP/1.1
2.0	HTTP/2
3.0	HTTP/3
SPDY	SPDY protocol.
QUIC	QUIC protocol.