Fern API Definition

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://raw.githubusercontent.com/api-evangelist/fern/main/json-schema/fern-api-definition-schema.json",
  "title": "Fern API Definition",
  "description": "Schema describing a Fern-managed API definition. A Fern project can be authored from one of several upstream sources (OpenAPI, AsyncAPI, Protobuf, OpenRPC, or the Fern Definition Language) and produces SDKs and documentation as outputs.",
  "type": "object",
  "required": ["id", "name", "source"],
  "properties": {
    "id": {
      "type": "string",
      "description": "Stable identifier for the API definition inside a Fern project."
    },
    "name": {
      "type": "string",
      "description": "Human-friendly API name."
    },
    "version": {
      "type": "string",
      "description": "API version string, semantic version preferred."
    },
    "description": {
      "type": "string",
      "description": "Free-form description of the API."
    },
    "source": {
      "type": "object",
      "description": "Upstream source of truth that Fern reads to generate SDKs and docs.",
      "required": ["type"],
      "properties": {
        "type": {
          "type": "string",
          "enum": ["openapi", "asyncapi", "protobuf", "openrpc", "fern-definition"]
        },
        "path": {"type": "string"},
        "url": {"type": "string", "format": "uri"},
        "overrides": {"type": "string"}
      }
    },
    "protocols": {
      "type": "array",
      "description": "Wire protocols this API exposes.",
      "items": {
        "type": "string",
        "enum": ["rest", "websocket", "grpc", "webhook", "json-rpc"]
      }
    },
    "auth": {
      "type": "object",
      "description": "Authentication scheme metadata for SDK generators and docs.",
      "properties": {
        "schemes": {
          "type": "array",
          "items": {
            "type": "string",
            "enum": ["bearer", "basic", "api-key", "oauth2", "jwt", "header", "custom"]
          }
        }
      }
    },
    "environments": {
      "type": "array",
      "description": "Named environments (e.g. production, sandbox) used by generated SDKs.",
      "items": {
        "type": "object",
        "required": ["name", "url"],
        "properties": {
          "name": {"type": "string"},
          "url": {"type": "string", "format": "uri"},
          "default": {"type": "boolean"}
        }
      }
    }
  }
}