Telemetry event definitions and emission helpers for x402 operations.
All events emitted by this library use the [:x402, module, operation] format
and include %{count: 1} as measurements.
Emitted events:
[:x402, :payment_required, :encode][:x402, :payment_required, :decode][:x402, :payment_signature, :decode][:x402, :payment_signature, :validate][:x402, :payment_signature, :decode_and_validate][:x402, :payment_response, :encode][:x402, :payment_response, :decode][:x402, :extension_responses, :decode][:x402, :payment_identifier, :legacy]— a deprecatedpaymentIdentifierformat id was received (metadata:sourceis:gateor:mcp)[:x402, :siwx, :legacy]— a deprecated{message, signature}SIGN-IN-WITH-Xheader was received (metadata:sourceis:gate)[:x402, :client, :select][:x402, :client, :sign][:x402, :client, :build][:x402, :client, :request][:x402, :client, :siwx]— a payer client answered a Sign-In-With-X challenge (metadata:transport,:chain_id, and:outcome—:authenticatedor:payment_required— or:reasonon error).:chain_idis the selected signing chain, never:auto, and isnilon errors before chain selection. DirectX402.Client.SIWXcalls default:transporttonil; HTTP/MCP drivers always identify it.[:x402, :rpc, :request][:x402, :verify, :evm][:x402, :verify, :svm][:x402, :facilitator_engine, :verify][:x402, :facilitator_engine, :settle]
Metadata always includes :status (:ok or :error) and may include
additional operation-specific fields such as :reason, :header, or
:fields.
Other modules emit events outside this helper — the payment gate
([:x402, :plug, ...]), the MCP transport ([:x402, :mcp, ...]), and
the facilitator client (:telemetry.span/3 events under
[:x402, :facilitator, operation] plus [:x402, :facilitator, :failover]).
events/0 lists every event name the library can emit, and
X402.Telemetry.Metrics / X402.Telemetry.Stats build on that list.
Summary
Functions
Emits an x402 telemetry event.
Returns the telemetry event name for a module and operation.
Returns every telemetry event name this library can emit.
Returns the facilitator client operations instrumented with :telemetry.span/3.
Types
@type event() :: [atom(), ...]
A telemetry event name emitted by this library.
@type module_name() ::
:payment_required
| :payment_signature
| :payment_response
| :extension_responses
| :payment_identifier
| :siwx
| :client
| :rpc
| :verify
| :facilitator_engine
@type operation() ::
:encode
| :decode
| :validate
| :decode_and_validate
| :select
| :sign
| :build
| :request
| :evm
| :svm
| :verify
| :settle
| :legacy
| :siwx
@type status() :: :ok | :error
Functions
@spec emit(module_name(), operation(), status(), map()) :: :ok
Emits an x402 telemetry event.
Examples
iex> X402.Telemetry.emit(:payment_required, :encode, :ok, %{header: "PAYMENT-REQUIRED"})
:ok@spec event_name(module_name(), operation()) :: [atom()]
Returns the telemetry event name for a module and operation.
Examples
iex> X402.Telemetry.event_name(:payment_required, :encode)
[:x402, :payment_required, :encode]@spec events() :: [event()]
Returns every telemetry event name this library can emit.
Span operations (X402.Facilitator verify, settle, supported, discovery)
are listed as their :start, :stop, and :exception events.
Examples
iex> [:x402, :plug, :rate_limited] in X402.Telemetry.events()
true
iex> [:x402, :facilitator, :settle, :stop] in X402.Telemetry.events()
true@spec facilitator_operations() :: [atom()]
Returns the facilitator client operations instrumented with :telemetry.span/3.
Examples
iex> X402.Telemetry.facilitator_operations()
[:verify, :settle, :supported, :list_resources, :search_resources]