Specificationv1.57.0

20 May 2026since v1.56.0

5 breaking22 notable22 editorial

From the upstream release notes

Add in-development Bind API to synchronous instruments.
Clarify that View-provided metric stream name is not subject to instrument
Define the Core packages term.
Rework contributing guide to reflect current process.
Stabilize sections of Prometheus and OpenMetrics Compatibility.
Stabilize sections of Prometheus Metrics Exporter.
Change Prometheus Metric Exporter config property recommended names
Clarify that OTel SDKs should not use unofficial Prometheus clients.
Add OTEP for Semantic Convention Schema v2 with support for multiple convention

Read the full release notes

Breaking5

Requirements added to, removed from, or restrengthened in a document marked Stable.

new rulerequirementmetrics/api.md#bindMUST added: This API MUST accept the following parameter:
new rulerequirementmetrics/api.md#bindMUST added: Therefore, this API MUST be structured to accept a variable number of attributes, including none.
new rulerequirementmetrics/api.md#bindMUST added: This API MUST return a language-idiomatic type representing the instrument bound to those attributes.
new rulerequirementmetrics/api.md#bindMUST added: The returned bound instrument MUST support the instrument's core recording operation.
new rulerequirementmetrics/api.md#bindMUST added: If the existing instrument interface is reused, the Bind API MUST be documented to communicate to users that invoking attribute-bearing recording operations on the returned bound instrument negates the performance ben...

Notable22

rule droppedrequirementcompatibility/prometheus_and_openmetrics.md#gauges-1MUST removed: Otherwise, it MUST be converted to a Prometheus Gauge.
rule droppedrequirementcompatibility/prometheus_and_openmetrics.md#instrumentation-scope-1MUST removed: Scope attributes with names 'name', 'version', or 'schemaurl' MUST be dropped to avoid conflicts with the already existing otelscopename, otelscopeversion, and otelscopeschema_url labels.
rule droppedrequirementcompatibility/prometheus_and_openmetrics.md#sumsMUST removed: If the aggregation temporality is cumulative and the sum is non-monotonic and the prometheus.type key of [metric.metadata][metricMetadata] is stateset, it MUST be converted to an OpenMetrics StateSet metric.
rule droppedrequirementcompatibility/prometheus_and_openmetrics.md#sumsMUST removed: If the aggregation temporality is cumulative and the sum is non-monotonic, it MUST be converted to a Prometheus Gauge.
rule droppedrequirementcompatibility/prometheus_and_openmetrics.md#sumsMUST removed: Otherwise, it MUST be dropped.
strengthrequirementcompatibility/prometheus_and_openmetrics.md#sumsMUST relaxed to MAY: If the aggregation temporality is delta and the sum is monotonic, it MAY be converted to a cumulative temporality and become a Prometheus Counter.
strengthrequirementsdk_exporters/prometheus.md#client-librariesSHOULD relaxed to SHOULD NOT: A Prometheus Exporter SHOULD use an official Prometheus client library when one exists for the implementation language and it is practical to do so (e.g., dependency concerns) for serving Prometheus ...
strengthrequirementsdk_exporters/prometheus.md#version-and-formatMUST NOT relaxed to SHOULD NOT: A Prometheus Exporter for an OpenTelemetry metrics SDK SHOULD NOT add explicit timestamps on Metric points.
new rulerequirementcompatibility/prometheus_and_openmetrics.md#gauges-1MUST added: If the prometheus.type key is absent, or its value is equal to gauge, the datapoint MUST be transformed to a Prometheus Gauge.
new rulerequirementcompatibility/prometheus_and_openmetrics.md#gauges-1MUST added: If the prometheus.type key has value equal to unkown, the datapoint MUST be transformed to a Prometheus Unknown.
new rulerequirementcompatibility/prometheus_and_openmetrics.md#instrumentation-scope-1MUST added: Scope attributes that, after adding the otelscope prefix and applying the label-name conversion described in Metric Attributes, would conflict with otelscopename, otelscopeversion, or otelscopeschemaurl MUST b...
new rulerequirementcompatibility/prometheus_and_openmetrics.md#sumsMUST added: An OpenTelemetry Sum MUST be converted following the rules below:
new rulerequirementmetrics/api.md#bindMAY added: This MAY be achieved by introducing a dedicated bound instrument type, or by reusing the existing instrument interface.
new rulerequirementmetrics/api.md#general-operationsMAY added: All synchronous instruments MAY provide:
new rulerequirementmetrics/sdk.md#instrument-bindMUST added: A bound instrument MUST behave identically to calling the equivalent unbound recording operation with the pre-bound Attributes on each measurement.
new rulerequirementmetrics/sdk.md#instrument-bindMUST added: Attribute processing and cardinality limit evaluation MUST be performed at bind time.
new rulerequirementmetrics/sdk.md#instrument-bindMUST added: Each call to Bind MUST be independently evaluated against the cardinality state at that moment.
new rulerequirementmetrics/sdk.md#instrument-bindMUST added: The resolved aggregator MUST be fixed and not change across collection cycles.
new rulerequirementmetrics/sdk.md#instrument-bindMUST added: Measurements recorded on a bound instrument MUST be candidates for Exemplar sampling.
new rulerequirementmetrics/sdk.md#instrument-bindMUST added: The Context associated with each recording, whether implicit or explicit, MUST be used for exemplar TraceBased filtering and passed to the ExemplarReservoir offer method.
new rulerequirementmetrics/sdk.md#instrument-bindMUST added: The SDK MUST ensure attribute-free recordings on a bound instrument bypass per-recording map lookup.
new rulerequirementmetrics/sdk.md#stream-configurationMUST NOT added: The name provided via stream configuration is NOT REQUIRED to conform to the instrument name syntax, and the SDK MUST NOT validate it against that syntax.

Editorial22

rule droppedrequirementcompatibility/prometheus_and_openmetrics.md#sumsSHOULD removed: If the aggregation temporality is delta and the sum is monotonic, it SHOULD be converted to a cumulative temporality and become a Prometheus Counter.
rule droppedrequirementcompatibility/prometheus_and_openmetrics.md#sumsSHOULD removed: Exporters SHOULD provide a configuration option to disable the addition of total suffixes.
new rulerequirementcompatibility/prometheus_and_openmetrics.md#gauges-1SHOULD added: If the prometheus.type key has value equal to info, the datapoint SHOULD be transformed to a Prometheus Info.
new rulerequirementcompatibility/prometheus_and_openmetrics.md#gauges-1SHOULD added: If the prometheus.type key has value equal to stateset, the datapoint SHOULD be transformed to a Prometheus Stateset.
new rulerequirementcompatibility/prometheus_and_openmetrics.md#sumsSHOULD added: Monotonic Sum metric points with StartTimeUnixNano SHOULD transform StartTimeUnixNano into Prometheus StartTime, following the appropriate format used by each Prometheus protocol.
new rulerequirementmetrics/sdk.md#stream-configurationSHOULD added: SDK documentation SHOULD inform users that attributes excluded from a metric stream by View configuration may still be exported on Exemplars as filtered attributes, and describe how to disable or otherwise configure Exe...
rewordedrequirementcompatibility/prometheus_and_openmetrics.md#gauges-1MUST reworded: An OpenTelemetry Gauge MUST be converted following a hint present in [metric.metadata][metricMetadata]:
rewordedrequirementcontext/api-propagators.md#propagators-distributionMUST reworded: The official list of propagators that MUST be maintained by the OpenTelemetry organization and MUST be distributed as OpenTelemetry Core packages:
rewordedrequirementcontext/api-propagators.md#propagators-distributionMAY reworded: This is a list of additional propagators that MAY be maintained and distributed as OpenTelemetry Core packages:
rewordedrequirementcontext/api-propagators.md#propagators-distributionMUST NOT reworded: Additional Propagators implementing vendor-specific protocols such as AWS X-Ray trace header protocol MUST NOT be maintained or distributed as part of the OpenTelemetry Core packages.
rewordedrequirementcontext/env-carriers.md#propagator-mechanismsMUST NOT reworded: The environment variable carrier MUST be format-agnostic and MUST treat values as opaque strings and MUST NOT apply propagation-format-specific logic such as validating, parsing values, or enforcing ...
rewordedrequirementsdk_exporters/prometheus.md#resource-attributes-as-metric-attributesMAY reworded: The option MAY be named resourceconstantlabels.
rewordedrequirementsdk_exporters/prometheus.md#scope-infoMAY reworded: A Prometheus Exporter MAY support configuration to specify whether metrics include scope labels.
rewordedrequirementsdk_exporters/prometheus.md#scope-infoMUST reworded: The option MAY be named scopeinfoenabled, and MUST be true by default.
rewordedrequirementsdk_exporters/prometheus.md#target-infoMAY reworded: A Prometheus Exporter MAY support a configuration to specify whether to produce a target info metric.
rewordedrequirementsdk_exporters/prometheus.md#target-infoMUST reworded: The option MAY be named targetinfoenabled, and MUST be true by default.
rewordedrequirementresource/sdk.md#sdk-provided-resource-attributesMUST reworded: This resource MUST be associated with a TracerProvider, MeterProvider, or LoggerProvider if another resource was not explicitly specified.
rewordedrequirementtrace/sdk.md#id-generatorsMUST NOT reworded: Additional IdGenerator implementing vendor-specific protocols such as AWS X-Ray trace ID generator MUST NOT be maintained or distributed as part of the OpenTelemetry Core packages.
addedsectionmetrics/api.md#bindNew section "Bind".
addedsectionmetrics/sdk.md#instrument-bindNew section "Instrument bind".
addedsectionspecification/overview.md#core-packagesNew section "Core Packages".
rewrittensectioncompatibility/prometheus_and_openmetrics.md#gauges-1"Gauges" substantially rewritten (350 to 729 characters).