API Commons · Models · de facto
The OpenAI Interface
211 providers in the API Evangelist catalog state OpenAI compatibility. 120 of them publish an OpenAPI harvested byte-identical from their own site, and those are the denominator. A provider may implement an operation without publishing a spec, so these shares are a floor.
How it was measured
Tiers are measured against what adopters publish, not asserted. Each METHOD and path is graded by the share of the publishing cohort that declares it. Grading by path alone credits every method on a path equally, which is wrong: GET and POST on /chat/completions are not implemented at the same rate.
The core tier
What a provider has to implement before a compatibility claim means anything. Every placement is measured, and the evidence for each sits in the tier profile.
POSTGET
Adopters
| Evidence | Count | What it means |
|---|---|---|
| declared | 101 | Publishes a machine-readable spec declaring them. |
| prose | 74 | Says so, and publishes nothing a reader can check. |
Every entry in the registry carries the URL it was read from and the date it was read. A claim is never promoted to a verdict.
Providers that reach a tier
67 of the 175 recorded adopters demonstrably reach the core tier or better. The 24 below link to their catalog pages; the registry and matrix carry the rest.
.txt0G LabsAIMLAPIAleph AlphaCentMLCerebras SystemsCometAPIDeepInfraDeepSeekEden AIEdgeeEnvoyFeatherless AIFlexAIGroqHugging FaceHyperbolicHyperbolicKimi (Moonshot AI)LangDBMistral AIMoonshot AIMultiverse ComputingNexGen Cloud
Artifacts
Everything this standard publishes. All of it is generated from the profile, so a re-measurement moves every artifact together.
models/main/standard/openai-v1/openapi.yml
OpenAPI Overlay
models/main/standard/openai-v1/overlay.yml
Arazzo workflow
models/main/standard/openai-v1/arazzo/core-conformance.yml
MCP tools
models/main/standard/openai-v1/mcp/tools.json
Spectral ruleset
models/main/standard/openai-v1/spectral/openai-profile.yaml
Adopter registry
models/main/adopters/openai-v1.yml
Repository
models
Documentation
https://apicommons.org/standards/models/
License
models/blob/main/LICENSE
Source
| Originator | OpenAI |
| Read from | https://github.com/openai/openai-openapi |
| Upstream licence | MIT |
| Pinned at | 38170fdddbb6a1813eae6c6587ee17cf2987185b |
| API Commons | https://apicommons.org/standards/models/ · https://github.com/api-commons/models |