Spans and attributes
- Currently supported spans and attributes

Spans and attributes

Last updated Oct 16, 2026 Cloudflare Workers provides automatic tracing instrumentation out of the box - no code changes or SDK are required.

Currently supported spans and attributes

Attributes available on all spans

cloud.provider - Always set to cloudflare
cloud.platform - Always set to cloudflare.workers
faas.name - The name of your Worker
faas.invocation_id - A unique identifier for this specific Worker invocation
faas.version - The deployed version tag of your Worker
faas.invoked_region - The region where the Worker was invoked
service.name - The name of your Worker
cloudflare.colo - The three-letter IATA airport code of the Cloudflare data center that processed the request (e.g., SFO, LHR)
cloudflare.script_name - The name of your Worker
cloudflare.script_tags - Tags associated with your Worker deployment
cloudflare.script_version.id - The version identifier of your deployed Worker
cloudflare.durable_object.id - The Durable Object instance ID, set on root and child spans for Durable Object invocations
cloudflare.invocation.sequence.number - A counter added to every emitted span and log that can be used to distinguish which was emitted first when the timestamps are the same
telemetry.sdk.language - The programming language used, set to javascript
telemetry.sdk.name - The telemetry SDK name, set to cloudflare

Attributes available on all root spans

faas.trigger - The trigger that your Worker was invoked by (e.g., http, cron, queue, email)
cloudflare.ray_id - A unique identifier for every request that goes through Cloudflare
cloudflare.handler_type - The type of handler that processed the request (e.g., fetch, scheduled, queue, email, alarm)
cloudflare.entrypoint - The entrypoint that was invoked in your Worker (e.g. the name of your Durable Object)
cloudflare.execution_model - The execution model of the Worker (e.g., stateless, stateful for Durable Objects)
cloudflare.outcome - The outcome of the Worker invocation (e.g., ok, exception, exceededCpu, exceededMemory)
cloudflare.cpu_time_ms - The CPU time used by the Worker invocation, in milliseconds
cloudflare.wall_time_ms - The wall time used by the Worker invocation, in milliseconds

Warning attributes

Workers tracing may attach warning attributes to a span when a non-fatal error condition is encountered while recording telemetry for that span. These are diagnostic indicators about the span's telemetry state (for example, a span that was never closed). When present, both attributes are set together.

cloudflare.warning.type - A closed-set identifier indicating the type of warning condition encountered. See Warning types for the set of defined values.
cloudflare.warning.message - A free-form, human-readable explanation of the warning condition.

Warning types

The following values are defined for cloudflare.warning.type:

span_not_ended - The span was still open when its parent invocation span closed. Workers tracing force-closes the span and attaches this warning.

Runtime API

`fetch`

network.protocol.name
network.protocol.version
url.full
url.scheme
url.path
url.query
server.port
server.address
user_agent.original
http.request.method
http.request.header.content-type
http.request.header.content-length
http.request.header.accept
http.request.header.accept-encoding
http.request.body.size
http.response.status_code
http.response.body.size

`cache_put`

cache.request.url
cache.request.method
cache.request.payload.status_code
cache.request.payload.header.cache_control
cache.request.payload.header.cache_tag
cache.request.payload.header.etag
cache.request.payload.header.expires
cache.request.payload.header.last_modified
cache.request.payload.size
cache.response.success

`cache_match`

cache.request.ignore_method
cache.request.url
cache.request.method
cache.request.header.range
cache.request.header.if_modified_since
cache.request.header.if_none_match
cache.response.status_code
cache.response.body.size
cache.response.cache_status
cache.response.success

`cache_delete`

cache.request.ignore_method
cache.request.url
cache.request.method
cache.response.status_code
cache.response.success

Handlers

`Fetch Handler`

cloudflare.verified_bot_category
cloudflare.asn
cloudflare.response.time_to_first_byte_ms
geo.timezone
geo.continent.code
geo.country.code
geo.locality.name
geo.locality.region
user_agent.original
user_agent.os.name
user_agent.os.version
user_agent.browser.name
user_agent.browser.major_version
user_agent.browser.version
user_agent.engine.name
user_agent.engine.version
user_agent.device.type
user_agent.device.vendor
user_agent.device.model
http.request.method
http.request.header.accept
http.request.header.accept-encoding
http.request.header.accept-language
url.full
url.path
network.protocol.name

`Scheduled Handler`

faas.cron
cloudflare.scheduled_time

`QueueHandler`

cloudflare.queue.name
cloudflare.queue.batch_size

`RPC Handler`

jsrpc.method

`Email Handler`

cloudflare.email.from
cloudflare.email.to
cloudflare.email.size

`Tail Handler`

cloudflare.trace.count

`Alarm Handler`

cloudflare.scheduled_time

RPC

Workers tracing emits these spans for RPC calls between Workers and from Workers to Durable Objects.

RPC session

A caller-side span that covers the lifetime of an RPC session. Calls that reuse the session appear under this span.

This span has no additional RPC-specific attributes.

RPC invocation

A callee-side span that covers an RPC invocation in the target Worker or Durable Object.

RPC call

A caller-side or callee-side span for an individual method call or property access.

Caller-side and callee-side spans use the execution color of the Worker or Durable Object where they run. The color change marks the execution boundary.

jsrpc.method - The method name or property path
jsrpc.operation - The operation type: call or getProperty
jsrpc.target_kind - The type of RPC target
jsrpc.caller_span_id - On callee-side spans, the corresponding caller-side jsRpcCall span ID