Specification
Variants seen in the corpus:
Specificationspecification
Providers using this tag (49)
Ranked by API Evangelist rating — Exemplar and Strong are expanded by default.
Strong 1 Solid coverage with minor gaps
Developing 4 Usable, with meaningful gaps to close
Thin 12 Limited public surface area
Emerging 30 Early or largely undocumented
The Update Framework (TUF)Zero-Trust Security ModelYoukiApache ArrowAgentic Resource Discovery (ARD)ApiaryModel Context Protocol (MCP)APIs.jsonContainer Network Interface (CNI)BICSSmithyCloud Native BuildpacksOverture Maps FoundationTest SpecificationsRSSService Mesh Interface (SMI)FOCUS (FinOps Open Cost and Usage Specification)RESTOpenAPICap'n ProtoGraphQLBean ValidationComponent ModelJakarta EEEventsMargoContinuous Delivery FoundationJAX-WSApache ParquetEditorConfig
Minimal 2 Almost no public developer surface
APIs with this tag (61)
Ranked by the provider's API Evangelist rating — the Kin Score is scored per provider, not per API, so every API of a provider shares its band. How the rating works →
Strong 1 Solid coverage with minor gaps
Developing 6 Usable, with meaningful gaps to close
Jentic API AI-Readiness Framework (JAIRF)Technical specification for evaluating how interpretable, operable, and trustworthy an API is for AI system...Agent Connect Protocol (ACP)A standard REST interface for invoking and configuring remote agents: agent discovery and descriptors, stat...Buildpack SpecificationThe Buildpack API (currently 0.12) defines the contract between an individual buildpack and the lifecycle. ...Image Extension SpecificationImage extensions emit Dockerfile snippets applied by the `extender` lifecycle binary to the build and/or ru...Platform SpecificationThe Platform API (currently 0.15) defines how platforms (pack, kpack, Tekton Pipelines, GitLab Auto DevOps,...VTEX Specification APIThe Specification API from VTEX — 2 operation(s) for specification.
Thin 12 Limited public surface area
Kalshi AsyncAPI SpecificationMachine-readable AsyncAPI description of the Kalshi WebSocket streaming API. Suitable for generating async ...Arazzo Specification (Redocly Tooling)Arazzo is the OpenAPI Initiative's specification for describing multi-step API workflows; Redocly is a prim...CloudEvents SpecificationThe CloudEvents specification defines a set of metadata attributes that must be present in every event, inc...CloudEvents SQL (CESQL)CloudEvents SQL (CESQL) is a v1.0 specification that defines a standardized query language for filtering an...THORChain Specification APIThe Specification API from THORChain — 2 operation(s) for specification.LAPIS SpecificationThe LAPIS specification defines a token-minimal, LLM-native format for describing HTTP APIs. A LAPIS docume...SUB Göttingen TextAPITextAPI is an open specification developed by SUB Göttingen for serving text and metadata of digital object...docomo Mail IMAP InterfaceThe docomo Mail IMAP interface is the one machine-interface specification NTT DOCOMO publishes openly, with...AsyncAPI SpecificationThe AsyncAPI Specification is an open standard for describing asynchronous and event-driven APIs. It provid...in-toto Attestation FrameworkThe in-toto Attestation Framework provides a specification for generating verifiable claims about any aspec...in-toto Attestation SpecificationThe in-toto specification defines the metadata format for recording software supply chain steps. It include...Notary Project Signing SpecificationThe Notary Project specification defines the signature envelope format, trust store and trust policy for co...
Emerging 42 Early or largely undocumented
TUF Repository SpecificationThe TUF specification defines the structure of update repositories including the root, targets, snapshot, a...NIST SP 800-207 Zero Trust ArchitectureThe foundational specification of the Zero Trust security model. Defines the seven tenets, the PDP/PEP/PA l...OCI Spec for Rustoci-spec-rs is a Rust implementation of the OCI Runtime, Image, and Distribution Specifications, providing ...Apache Arrow Format SpecificationThe Apache Arrow columnar format specification defines the binary layout for in-memory columnar data, inclu...API BlueprintAPI Blueprint is a high-level API design language created by Apiary for designing and documenting web APIs....MCP SpecificationThe authoritative protocol definition for the Model Context Protocol, maintained at modelcontextprotocol.io...APIs.json SpecificationThe APIs.json specification defines a machine-readable JSON or YAML format for describing API operations. U...CNI SpecificationThe CNI specification defines the interface between container runtimes and network plugins. It specifies ho...BICS specification APIThe specification API from BICS — 1 operation(s) for specification.Smithy IDLThe Smithy Interface Definition Language (IDL) is a specification for defining API models using shapes and ...Buildpack APIThe Buildpack API is the contract between a buildpack and the lifecycle. It defines the detect and build ex...Distribution APIThe Distribution API specifies how buildpacks and builders are packaged as OCI artifacts, signed, and distr...Platform APIThe Platform API is the contract between the CNB lifecycle and a platform such as pack, kpack, or a CI runn...AsyncAPI InitiativeAsyncAPI is an open specification standard for event-driven and message-based APIs. AsyncAPI documents defi...JSON SchemaJSON Schema provides a vocabulary for annotating and validating JSON documents. Used extensively as the pay...OpenAPI InitiativeThe OpenAPI Specification (OAS) is the de-facto standard for describing RESTful APIs. OpenAPI documents ser...Overture SchemaCanonical open schema specification for all Overture themes, maintained in the OvertureMaps/schema GitHub r...Pact Contract TestingPact is a consumer-driven contract testing tool where consumers write test specifications (pacts) that defi...SpectralSpectral is an open-source JSON/YAML linter and specification validator. It evaluates OpenAPI, AsyncAPI, an...Atom 1.0Atom 1.0, defined by IETF RFC 4287, is an XML-based syndication format developed as a more rigorously speci...JSON Feed 1.1JSON Feed 1.1 is a JSON-based syndication format created by Brent Simmons and Manton Reece as a developer-f...RSS 2.0RSS 2.0 is the dominant XML-based syndication format, stewarded by the RSS Advisory Board. A feed consists ...FOCUS (FinOps Open Cost and Usage Specification)FOCUS defines a common normalized data schema for cloud and technology billing data. The specification is d...JSON:APIJSON:API is a specification for how a client should request that resources be fetched or modified, and how ...OpenAPI SpecificationThe OpenAPI Specification (OAS) defines a standard, language-agnostic interface to RESTful APIs which allow...Cap'n Proto Encoding (Wire Format)The Cap'n Proto encoding specification defines the binary wire format. The in-memory layout is the wire for...Cap'n Proto RPC ProtocolCap'n Proto's RPC protocol is a capability-based RPC layer that supports promise pipelining, object referen...Cap'n Proto Schema LanguageThe Cap'n Proto schema language is used to define message types in .capnp files that are then compiled into...Jakarta Bean Validation Specification 3.1The Jakarta Bean Validation 3.1 specification defines the constraint model, annotation processor, Validator...WebAssembly Component Model SpecificationThe Component Model specification repository under the W3C WebAssembly Community Group. Contains design doc...Jakarta JSON BindingJakarta JSON Binding (formerly JSON-B) is a binding framework for converting Java objects to and from JSON ...Jakarta JSON ProcessingJakarta JSON Processing (formerly JSON-P) provides an API to parse, generate, transform, and query JSON doc...Jakarta RESTful Web ServicesJakarta RESTful Web Services (formerly JAX-RS) is the API specification for developing web services that fo...Jakarta ServletJakarta Servlet is a server-side Java API for handling HTTP requests and generating dynamic responses. It p...Jakarta ValidationJakarta Validation (formerly Bean Validation) provides an object-level constraint declaration and validatio...Jakarta WebSocketJakarta WebSocket defines a standard API for creating server and client endpoints that communicate using th...AsyncAPILinux Foundation-hosted specification for event-driven APIs. Describes servers, channels, operations, messa...CloudEventsCNCF-graduated specification (graduated January 25, 2024) for describing event data in a common way. Define...Margo SpecificationMargo defines an open standard specification for interoperability of edge applications, devices, and orches...CDEvents SpecificationCDEvents is a common specification for Continuous Delivery events that enables interoperability across CI/C...Jakarta XML Web Services (JAX-WS)The Jakarta EE specification for XML web services, formerly JSR 224 JAX-WS. Defines annotations such as @We...Apache Parquet Format SpecificationThe core specification for the Parquet columnar storage format.
Score breakdown
Frequency
51.4
log-scaled weighted occurrences
Breadth
1.3
spread across providers
Quality lift
29.2
mean composite of providers using it
Cohesion
8.0
strength of nearest seed neighbor
Related tags
Standards 12 co-occurrences
Linux Foundation 7 co-occurrences
CNCF 6 co-occurrences
Cloud-Native 8 co-occurrences
Schema 5 co-occurrences
Python 10 co-occurrences
OpenAPI 7 co-occurrences
Java 6 co-occurrences
Where this tag comes from
Provider tag19
Api tag61
Openapi tag3
Openapi op tag6
Cohort brief
Auto-generatedThe 49 providers in the APIs.io catalog tagged Specification, scored on the Kin Score. Every figure below is computed from the catalog — nothing here is written.
Providers
49
all scored
Mean Kin Score
24.5
+3.8 vs catalog 20.7
Mean Agent Readiness
8.9
-0.8 vs catalog 9.7
Spread
6.4–59.8
median 22.3 · σ 11.2
How the 49 split by band
Exemplar 0Strong 1Developing 4Thin 12Emerging 30Minimal 2
Facet averages, against the whole catalog
| Facet | This cohort | Catalog | Difference | Scored |
|---|---|---|---|---|
| Operational Transparency | 19.4 | 11.3 | +8.1 | 49 |
| Contract Governance | 12.5 | 6.4 | +6.1 | 49 |
| Contract Quality | 23.4 | 17.5 | +5.9 | 49 |
| Discoverability | 65.6 | 60.4 | +5.2 | 49 |
| Developer Ergonomics | 22.8 | 17.9 | +4.9 | 49 |
| Access Clarity | 16.8 | 22.3 | -5.5 | 49 |
A facet is averaged over the members that carry it, not over the whole cohort — the “Scored” column is that count. Averaging an absent facet as zero would score our own coverage gaps as the providers’ posture.
What this cohort publishes
| Artifact | This cohort | Catalog | Difference |
|---|---|---|---|
| MCP server (any) | 6% | 16% | -10 |
| MCP server (first-party) | 4% | 7% | -3 |
| Agent Skills | 0% | 0% | 0 |
| OAuth scopes | 2% | 9% | -7 |
| Security | 92% | 88% | +4 |
| Arazzo workflows | 0% | 2% | -2 |
| Governance rules | 55% | 13% | +42 |
mcp_pct counts any mcp/ artifact including ones API Evangelist derived from the provider OpenAPI; mcp_first_party_pct counts only servers the provider publishes. Prefer the latter.
Top by Kin Score
- 1 GSMA 59.8
- 2 Jentic 51.8
- 3 AGNTCY 47.6
- 4 buildpacks-io 40.6
- 5 VTEX 40.5
- 6 Kalshi 39.1
- 7 Redocly 38.9
- 8 CloudEvents 38.5
- 9 THORChain 35.9
- 10 LAPIS 32.5
Top by Agent Readiness
- 1 GSMA 42.2
- 2 AGNTCY 34.2
- 3 Jentic 34.2
- 4 OpenFeature 33.1
- 5 VTEX 32.3
- 6 BICS 30.6
- 7 Kalshi 26.6
- 8 THORChain 26.4
- 9 University of Göttingen 22.7
- 10 AsyncAPI 21.6
All 49 members of this roster resolve to a scored provider in
the catalog.Generated from the catalog build of
25 August 2026, across 26891
providers, using the same computation served by the
APIs.io cohort API. Briefs are published for rosters of
5 or more scored providers; below that a distribution is not meaningful.
Work with this as data
Every tag here is available over the APIs.io API and to AI agents over MCP.
MCP server
One button, every client — Claude, Cursor, VS Code and the rest.
https://apis.io/mcp
Tools for tags
7 MCP tools reach this
find_tagsBrowse and filter every tag in the catalog.get_cohortThis tag as a scored cohort — every provider carrying it, with scores.cohort_statsPRO — the distribution across this tag: mean, median, band split, adoption rates.cohort_rankingsPRO — the leaderboard, on composite AND agent-readiness axes.apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.resolveTurn a domain, URL or GitHub org into the provider it belongs to.find_cohortsEvery scored population of providers in the catalog.
Call it yourself
curl for this page
This tag
curl "https://apis.io/api/v1/tags/specification"
All tags
curl "https://apis.io/api/v1/tags?limit=25"
As a scored cohort
curl "https://apis.io/api/v1/cohorts/tag/specification"
The distribution (Pro)
curl "https://apis.io/api/v1/cohorts/tag/specification/stats" \
-H "X-API-Key: $APIS_IO_KEY"Discovery needs no key. Ratings and market analysis are Pro.