Semantic Conventions for HTTP Spans

Status: Stable, Unless otherwise specified.

This document defines semantic conventions for HTTP client and server Spans. They can be used for http and https schemes and various HTTP versions like 1.1, 2 and SPDY.

Warning Existing HTTP instrumentations that are using v1.20.0 of this document (or prior):

• SHOULD NOT change the version of the HTTP or networking conventions that they emit until the HTTP semantic conventions are marked stable (HTTP stabilization will include stabilization of a core set of networking conventions which are also used in HTTP instrumentations). Conventions include, but are not limited to, attributes, metric and span names, and unit of measure.
• SHOULD introduce an environment variable OTEL_SEMCONV_STABILITY_OPT_IN in the existing major version which is a comma-separated list of values. The only values defined so far are:
  • http - emit the new, stable HTTP and networking conventions, and stop emitting the old experimental HTTP and networking conventions that the instrumentation emitted previously.
  • http/dup - emit both the old and the stable HTTP and networking conventions, allowing for a seamless transition.
  • The default behavior (in the absence of one of these values) is to continue emitting whatever version of the old experimental HTTP and networking conventions the instrumentation was emitting previously.
  • Note: http/dup has higher precedence than http in case both values are present
• SHOULD maintain (security patching at a minimum) the existing major version for at least six months after it starts emitting both sets of conventions.
• SHOULD drop the environment variable in the next major version.

Name

HTTP spans MUST follow the overall guidelines for span names.

HTTP span names SHOULD be {method} {target} if there is a (low-cardinality) target available. If there is no (low-cardinality) {target} available, HTTP span names SHOULD be {method}.

(see below for the exact definition of the {method} and {target} placeholders).

The {method} MUST be {http.request.method} if the method represents the original method known to the instrumentation. In other cases (when {http.request.method} is set to _OTHER), {method} MUST be HTTP.

The {target} SHOULD be one of the following:

• http.route for HTTP Server spans
• url.template for HTTP Client spans if enabled and available ()
• Other value MAY be provided through custom hooks at span start time or later.

Instrumentation MUST NOT default to using URI path as a {target}.

Status

Span Status MUST be left unset if HTTP status code was in the 1xx, 2xx or 3xx ranges, unless there was another error (e.g., network error receiving the response body; or 3xx codes with max redirects exceeded), in which case status MUST be set to Error.

Note:

The classification of an HTTP status code as an error depends on the context. For example, a 404 “Not Found” status code indicates an error if the application expected the resource to be available. However, it is not an error when the application is simply checking whether the resource exists.

Instrumentations that have additional context about a specific request MAY use this context to set the span status more precisely. Instrumentations that don’t have any additional context MUST follow the guidelines in this section.

For HTTP status codes in the 4xx range span status MUST be left unset in case of SpanKind.SERVER and SHOULD be set to Error in case of SpanKind.CLIENT.

For HTTP status codes in the 5xx range, as well as any other code the client failed to interpret, span status SHOULD be set to Error.

Don’t set the span status description if the reason can be inferred from http.response.status_code.

HTTP request may fail if it was cancelled or an error occurred preventing the client or server from sending/receiving the request/response fully.

When instrumentation detects such errors it SHOULD set span status to Error and SHOULD set the error.type attribute.

HTTP client

This span type represents an outbound HTTP request. There are two ways this can be achieved in an instrumentation:

1. Instrumentations SHOULD create an HTTP span for each attempt to send an HTTP request over the wire. In case the request is resent, the resend attempts MUST follow the HTTP resend spec. In this case, instrumentations SHOULD NOT (also) emit a logical encompassing HTTP client span.

2. If for some reason it is not possible to emit a span for each send attempt (because e.g. the instrumented library does not expose hooks that would allow this), instrumentations MAY create an HTTP span for the top-most operation of the HTTP client. In this case, the url.full MUST be the absolute URL that was originally requested, before any HTTP-redirects that may happen when executing the request.

For an HTTP client span, SpanKind MUST be Client.

Attribute	Type	Description	Examples	Requirement Level	Stability
http.request.method	string	HTTP request method. [1]	GET; POST; HEAD	Required
server.address	string	Host identifier of the “URI origin” HTTP request is sent to. [2]	example.com; 10.1.2.80; /tmp/my.sock	Required
server.port	int	Port identifier of the “URI origin” HTTP request is sent to. [3]	80; 8080; 443	Required
url.full	string	Absolute URL describing a network resource according to RFC3986 [4]	https://www.foo.bar/search?q=OpenTelemetry#SemConv; //localhost	Required
error.type	string	Describes a class of error the operation ended with. [5]	timeout; java.net.UnknownHostException; server_certificate_invalid; 500	Conditionally Required If request has ended with an error.
http.request.method_original	string	Original HTTP method sent by the client in the request line.	GeT; ACL; foo	Conditionally Required [6]
http.response.status_code	int	HTTP response status code.	200	Conditionally Required If and only if one was received/sent.
network.protocol.name	string	OSI application layer or non-OSI equivalent. [7]	http; spdy	Conditionally Required [8]
http.request.resend_count	int	The ordinal number of request resending attempt (for any reason, including redirects). [9]	3	Recommended if and only if request was retried.
network.peer.address	string	Peer address of the network connection - IP address or Unix domain socket name.	10.1.2.80; /tmp/my.sock	Recommended
network.peer.port	int	Peer port number of the network connection.	65123	Recommended If network.peer.address is set.
network.protocol.version	string	The actual version of the protocol used for network communication. [10]	1.0; 1.1; 2; 3	Recommended
http.request.header.<key>	string[]	HTTP request headers, <key> being the normalized HTTP Header name (lowercase), the value being the header values. [11]	http.request.header.content-type=["application/json"]; http.request.header.x-forwarded-for=["1.2.3.4", "1.2.3.5"]	Opt-In
http.response.header.<key>	string[]	HTTP response headers, <key> being the normalized HTTP Header name (lowercase), the value being the header values. [12]	http.response.header.content-type=["application/json"]; http.response.header.my-custom-header=["abc", "def"]	Opt-In
network.transport	string	OSI transport layer or inter-process communication method. [13]	tcp; udp	Opt-In
url.scheme	string	The URI scheme component identifying the used protocol.	http; https	Opt-In
user_agent.original	string	Value of the HTTP User-Agent header sent by the client.	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; YourApp/1.0.0 grpc-java-okhttp/1.27.2	Opt-In

[1]: 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.

[2]: If an HTTP client request is explicitly made to an IP address, e.g. http://x.x.x.x:8080, then server.address SHOULD be the IP address x.x.x.x. A DNS lookup SHOULD NOT be used.

[3]: When observed from the client side, and when communicating through an intermediary, server.port SHOULD represent the server port behind any intermediaries, for example proxies, if it’s available.

[4]: For network calls, URL usually has scheme://host[:port][path][?query][#fragment] format, where the fragment is not transmitted over HTTP, but if it is known, it SHOULD be included nevertheless. url.full MUST NOT contain credentials passed via URL in form of https://username:password@www.example.com/. In such case username and password SHOULD be redacted and attribute’s value SHOULD be https://REDACTED:REDACTED@www.example.com/. url.full SHOULD capture the absolute URL when it is available (or can be reconstructed). Sensitive content provided in url.full SHOULD be scrubbed when instrumentations can identify it.

[5]: If the request fails with an error before response status code was sent or received, error.type SHOULD be set to exception type (its fully-qualified class name, if applicable) or a component-specific low cardinality error identifier.

If response status code was sent or received and status indicates an error according to HTTP span status definition, error.type SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error identifier.

The error.type value SHOULD be predictable and SHOULD have low cardinality. Instrumentations SHOULD document the list of errors they report.

The cardinality of error.type within one instrumentation library SHOULD be low, but telemetry consumers that aggregate data from multiple instrumentation libraries and applications should be prepared for error.type to have high cardinality at query time, when no additional filters are applied.

If the request has completed successfully, instrumentations SHOULD NOT set error.type.

[6]: If and only if it’s different than http.request.method.

[7]: The value SHOULD be normalized to lowercase.

[8]: If not http and network.protocol.version is set.

[9]: 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).

[10]: If protocol version is subject to negotiation (for example using ALPN), this attribute SHOULD be set to the negotiated version. If the actual protocol version is not known, this attribute SHOULD NOT be set.

[11]: 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.

[12]: 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.

[13]: Generally tcp for HTTP/1.0, HTTP/1.1, and HTTP/2. Generally udp for HTTP/3. Other obscure implementations are possible.

The following attributes can be important for making sampling decisions and SHOULD be provided at span creation time (if provided at all):

• http.request.method
• server.address
• server.port
• url.full

error.type 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
_OTHER	A fallback error value to be used when the instrumentation doesn’t define a custom value.

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
_OTHER	Any HTTP method that the instrumentation has no prior knowledge of.
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.

network.transport 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
pipe	Named or anonymous pipe.
quic	QUIC
tcp	TCP
udp	UDP
unix	Unix domain socket

HTTP client experimental attributes

Status: Experimental

Instrumentations MAY allow users to enable additional experimental attributes.

Attribute	Type	Description	Examples	Requirement Level	Stability
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	Opt-In
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	Opt-In
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	Opt-In
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	Opt-In
url.template	string	The low-cardinality template of an absolute path reference. [1]	/users/{id}; /users/:id; /users?id={id}	Opt-In

[1]: The url.template MUST have low cardinality. It is not usually available on HTTP clients, but may be known by the application or specialized HTTP instrumentation.

HTTP client span duration

There are some minimal constraints that SHOULD be honored:

• HTTP client spans SHOULD start sometime before the first request byte is sent. This may or may not include connection time.
• HTTP client spans SHOULD end sometime after the HTTP response headers are fully read (or when they fail to be read). This may or may not include reading the response body.

If there is any possibility for application code to not fully read the HTTP response (and for the HTTP client library to then have to clean up the HTTP response asynchronously), the HTTP client span SHOULD NOT be ended in this cleanup phase, and instead SHOULD end at some point after the HTTP response headers are fully read (or fail to be read). This avoids the span being ended asynchronously later on at a time which is no longer directly associated with the application code which made the HTTP request.

Because of the potential for confusion around this, HTTP client library instrumentations SHOULD document their behavior around ending HTTP client spans.

HTTP request retries and redirects

Retries and redirects cause more than one physical HTTP request to be sent. A request is resent when an HTTP client library sends more than one HTTP request to satisfy the same API call. This may happen due to following redirects, authorization challenges, 503 Server Unavailable, network issues, or any other.

Each time an HTTP request is resent, the http.request.resend_count attribute SHOULD be added to each repeated span and set to the ordinal number of the request resend attempt.

See the examples for more details about:

• retrying a server error,
• redirects,
• authorization.

HTTP server

Read the following section to understand how HTTP server instrumentations are suggested to capture server information.

HTTP server definitions

An HTTP request can be routed to a specific HTTP application via intermediaries such as reverse proxies. HTTP requests sent to the same domain name may be handled by multiple applications depending on the port, path, headers, or other parameters.

For example, different versions of the same web-application can run side-by-side as independent applications behind the reverse proxy which routes request to one or another based on the request path.

Instances of different HTTP server applications may run on the same physical host and share the same IP address, but listen to different TCP/UDP ports. In order to route the request to a specific application, reverse proxies usually modify the HTTP Host header replacing the original value provided by the client with an actual proxied server name. This behavior depends on the reverse proxy configuration. In some cases, the Host header is not used when routing request to a specific application, making it prone to having bogus content.

HTTP server frameworks and their instrumentations have limited knowledge about the HTTP infrastructure and intermediaries that requests go through. In a general case, they can only use HTTP request properties such as request target or headers to populate server.* attributes.

Setting server.address and server.port attributes

In the context of HTTP server, server.address and server.port attributes capture the original host name and port. They are intended, whenever possible, to be the same on the client and server sides.

HTTP server instrumentations SHOULD do the best effort when populating server.address and server.port attributes and SHOULD determine them by using the first of the following that applies:

• The original host which may be passed by the reverse proxy in the Forwarded#host, X-Forwarded-Host, or a similar header.
• The :authority pseudo-header in case of HTTP/2 or HTTP/3
• The Host header.

Note: The Host and :authority headers contain host and port number of the server. The same applies to the host identifier of Forwarded header or the X-Forwarded-Host header. Instrumentations SHOULD populate both server.address and server.port attributes by parsing the value of corresponding header.

Application developers MAY overwrite potentially inaccurate values of server.* attributes using a SpanProcessor and MAY capture private host information using applicable resource attributes.

Simple client/server example

Client/server example with reverse proxy

HTTP server semantic conventions

This span type represents an inbound HTTP request.

For an HTTP server span, SpanKind MUST be Server.

Attribute	Type	Description	Examples	Requirement Level	Stability
http.request.method	string	HTTP request method. [1]	GET; POST; HEAD	Required
url.path	string	The URI path component [2]	/search	Required
url.scheme	string	The URI scheme component identifying the used protocol. [3]	http; https	Required
error.type	string	Describes a class of error the operation ended with. [4]	timeout; java.net.UnknownHostException; server_certificate_invalid; 500	Conditionally Required If request has ended with an error.
http.request.method_original	string	Original HTTP method sent by the client in the request line.	GeT; ACL; foo	Conditionally Required [5]
http.response.status_code	int	HTTP response status code.	200	Conditionally Required If and only if one was received/sent.
http.route	string	The matched route, that is, the path template in the format used by the respective server framework. [6]	/users/:userID?; {controller}/{action}/{id?}	Conditionally Required If and only if it’s available
network.protocol.name	string	OSI application layer or non-OSI equivalent. [7]	http; spdy	Conditionally Required [8]
server.port	int	Port of the local HTTP server that received the request. [9]	80; 8080; 443	Conditionally Required If server.address is set.
url.query	string	The URI query component [10]	q=OpenTelemetry	Conditionally Required If and only if one was received/sent.
client.address	string	Client address - domain name if available without reverse DNS lookup; otherwise, IP address or Unix domain socket name. [11]	83.164.160.102	Recommended
network.peer.address	string	Peer address of the network connection - IP address or Unix domain socket name.	10.1.2.80; /tmp/my.sock	Recommended
network.peer.port	int	Peer port number of the network connection.	65123	Recommended If network.peer.address is set.
network.protocol.version	string	The actual version of the protocol used for network communication. [12]	1.0; 1.1; 2; 3	Recommended
server.address	string	Name of the local HTTP server that received the request. [13]	example.com; 10.1.2.80; /tmp/my.sock	Recommended
user_agent.original	string	Value of the HTTP User-Agent header sent by the client.	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; YourApp/1.0.0 grpc-java-okhttp/1.27.2	Recommended
client.port	int	The port of whichever client was captured in client.address. [14]	65123	Opt-In
http.request.header.<key>	string[]	HTTP request headers, <key> being the normalized HTTP Header name (lowercase), the value being the header values. [15]	http.request.header.content-type=["application/json"]; http.request.header.x-forwarded-for=["1.2.3.4", "1.2.3.5"]	Opt-In
http.response.header.<key>	string[]	HTTP response headers, <key> being the normalized HTTP Header name (lowercase), the value being the header values. [16]	http.response.header.content-type=["application/json"]; http.response.header.my-custom-header=["abc", "def"]	Opt-In
network.local.address	string	Local socket address. Useful in case of a multi-IP host.	10.1.2.80; /tmp/my.sock	Opt-In
network.local.port	int	Local socket port. Useful in case of a multi-port host.	65123	Opt-In
network.transport	string	OSI transport layer or inter-process communication method. [17]	tcp; udp	Opt-In

[1]: 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.

[2]: Sensitive content provided in url.path SHOULD be scrubbed when instrumentations can identify it.

[3]: The scheme of the original client request, if known (e.g. from Forwarded#proto, X-Forwarded-Proto, or a similar header). Otherwise, the scheme of the immediate peer request.

[4]: If the request fails with an error before response status code was sent or received, error.type SHOULD be set to exception type (its fully-qualified class name, if applicable) or a component-specific low cardinality error identifier.

If response status code was sent or received and status indicates an error according to HTTP span status definition, error.type SHOULD be set to the status code number (represented as a string), an exception type (if thrown) or a component-specific error identifier.

The error.type value SHOULD be predictable and SHOULD have low cardinality. Instrumentations SHOULD document the list of errors they report.

The cardinality of error.type within one instrumentation library SHOULD be low, but telemetry consumers that aggregate data from multiple instrumentation libraries and applications should be prepared for error.type to have high cardinality at query time, when no additional filters are applied.

If the request has completed successfully, instrumentations SHOULD NOT set error.type.

[5]: If and only if it’s different than http.request.method.

[6]: 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.

[7]: The value SHOULD be normalized to lowercase.

[8]: If not http and network.protocol.version is set.

[9]: See Setting server.address and server.port attributes.

[10]: Sensitive content provided in url.query SHOULD be scrubbed when instrumentations can identify it.

[11]: The IP address of the original client behind all proxies, if known (e.g. from Forwarded#for, X-Forwarded-For, or a similar header). Otherwise, the immediate client peer address.

[12]: If protocol version is subject to negotiation (for example using ALPN), this attribute SHOULD be set to the negotiated version. If the actual protocol version is not known, this attribute SHOULD NOT be set.

[13]: See Setting server.address and server.port attributes.

[14]: When observed from the server side, and when communicating through an intermediary, client.port SHOULD represent the client port behind any intermediaries, for example proxies, if it’s available.

[15]: 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.

[16]: 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.

[17]: Generally tcp for HTTP/1.0, HTTP/1.1, and HTTP/2. Generally udp for HTTP/3. Other obscure implementations are possible.

The following attributes can be important for making sampling decisions and SHOULD be provided at span creation time (if provided at all):

• client.address
• http.request.header.<key>
• http.request.method
• server.address
• server.port
• url.path
• url.query
• url.scheme
• user_agent.original

error.type 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
_OTHER	A fallback error value to be used when the instrumentation doesn’t define a custom value.

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
_OTHER	Any HTTP method that the instrumentation has no prior knowledge of.
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.

network.transport 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
pipe	Named or anonymous pipe.
quic	QUIC
tcp	TCP
udp	UDP
unix	Unix domain socket

http.route MUST be provided at span creation time if and only if it’s already available. If it becomes available after span starts, instrumentation MUST populate it anytime before span ends.

HTTP server experimental attributes

Status: Experimental

Instrumentations MAY allow users to enable additional experimental attributes.

Attribute	Type	Description	Examples	Requirement Level	Stability
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	Opt-In
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	Opt-In
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	Opt-In
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	Opt-In

Examples

HTTP client-server example

As an example, if a browser request for https://example.com:8080/webshop/articles/4?s=1&t=2 is invoked from a host with IP 192.0.2.4, we may have the following Span on the client side:

Span name: GET

The corresponding server Span may look like this:

Span name: GET /webshop/articles/:article_id.

HTTP client retries examples

Example of retries in the presence of a trace started by an inbound request:

request (SERVER, trace=t1, span=s1)
  |
  -- GET / - 500 (CLIENT, trace=t1, span=s2)
  |   |
  |   --- server (SERVER, trace=t1, span=s3)
  |
  -- GET / - 500 (CLIENT, trace=t1, span=s4, http.request.resend_count=1)
  |   |
  |   --- server (SERVER, trace=t1, span=s5)
  |
  -- GET / - 200 (CLIENT, trace=t1, span=s6, http.request.resend_count=2)
      |
      --- server (SERVER, trace=t1, span=s7)

Example of retries with no trace started upfront:

GET / - 500 (CLIENT, trace=t1, span=s1)
 |
 --- server (SERVER, trace=t1, span=s2)

GET / - 500 (CLIENT, trace=t2, span=s1, http.request.resend_count=1)
 |
 --- server (SERVER, trace=t2, span=s2)

GET / - 200 (CLIENT, trace=t3, span=s1, http.request.resend_count=2)
 |
 --- server (SERVER, trace=t3, span=s1)

HTTP client authorization retry examples

Example of retries in the presence of a trace started by an inbound request:

request (SERVER, trace=t1, span=s1)
  |
  -- GET /hello - 401 (CLIENT, trace=t1, span=s2)
  |   |
  |   --- server (SERVER, trace=t1, span=s3)
  |
  -- GET /hello - 200 (CLIENT, trace=t1, span=s4, http.request.resend_count=1)
      |
      --- server (SERVER, trace=t1, span=s5)

Example of retries with no trace started upfront:

GET /hello - 401 (CLIENT, trace=t1, span=s1)
 |
 --- server (SERVER, trace=t1, span=s2)

GET /hello - 200 (CLIENT, trace=t2, span=s1, http.request.resend_count=1)
 |
 --- server (SERVER, trace=t2, span=s2)

HTTP client redirects examples

Example of redirects in the presence of a trace started by an inbound request:

request (SERVER, trace=t1, span=s1)
  |
  -- GET / - 302 (CLIENT, trace=t1, span=s2)
  |   |
  |   --- server (SERVER, trace=t1, span=s3)
  |
  -- GET /hello - 200 (CLIENT, trace=t1, span=s4, http.request.resend_count=1)
      |
      --- server (SERVER, trace=t1, span=s5)

Example of redirects with no trace started upfront:

GET / - 302 (CLIENT, trace=t1, span=s1)
 |
 --- server (SERVER, trace=t1, span=s2)

GET /hello - 200 (CLIENT, trace=t2, span=s1, http.request.resend_count=1)
 |
 --- server (SERVER, trace=t2, span=s2)

HTTP client call: DNS error

As an example, if a user requested https://does-not-exist-123.com, we may have the following span on the client side:

HTTP client call: Internal Server Error

As an example, if a user requested https://example.com and server returned 500, we may have the following span on the client side:

HTTP server call: connection dropped before response body was sent

As an example, if a user sent a POST request with a body to https://example.com:8080/uploads/4, we may see the following span on a server side:

Span name: POST /uploads/:document_id.