Example OpenAPI spec with webhooks

openapi.json

{
    "openapi": "3.1.0",
    "info": {
        "title": "FastAPI",
        "version": "0.1.0"
    },
    "paths": {
        "/pet": {
            "get": {
                "summary": "List Pets",
                "operationId": "list_pets_pet_get",
                "responses": {
                    "200": {
                        "description": "Successful Response",
                        "content": {
                            "application/json": {
                                "schema": {
                                    "items": {
                                        "$ref": "#/components/schemas/Pet"
                                    },
                                    "type": "array",
                                    "title": "Response List Pets Pet Get"
                                }
                            }
                        }
                    }
                }
            }
        }
    },
    "webhooks": {
        "pet.new": {
            "post": {
                "summary": "New Pet",
                "description": "When a new pet is created",
                "operationId": "new_petpet_new_post",
                "requestBody": {
                    "content": {
                        "application/json": {
                            "schema": {
                                "$ref": "#/components/schemas/PetNewEvent"
                            }
                        }
                    },
                    "required": true
                },
                "responses": {
                    "200": {
                        "description": "Successful Response",
                        "content": {
                            "application/json": {
                                "schema": {}
                            }
                        }
                    },
                    "422": {
                        "description": "Validation Error",
                        "content": {
                            "application/json": {
                                "schema": {
                                    "$ref": "#/components/schemas/HTTPValidationError"
                                }
                            }
                        }
                    }
                }
            }
        }
    },
    "components": {
        "schemas": {
            "HTTPValidationError": {
                "properties": {
                    "detail": {
                        "items": {
                            "$ref": "#/components/schemas/ValidationError"
                        },
                        "type": "array",
                        "title": "Detail"
                    }
                },
                "type": "object",
                "title": "HTTPValidationError"
            },
            "Pet": {
                "properties": {
                    "name": {
                        "type": "string",
                        "title": "Name"
                    },
                    "age": {
                        "type": "integer",
                        "title": "Age"
                    }
                },
                "type": "object",
                "required": [
                    "name",
                    "age"
                ],
                "title": "Pet"
            },
            "PetNewEvent": {
                "properties": {
                    "type": {
                        "type": "string",
                        "title": "Type",
                        "default": "pet.new"
                    },
                    "timestamp": {
                        "type": "string",
                        "format": "date-time",
                        "title": "Timestamp"
                    },
                    "data": {
                        "$ref": "#/components/schemas/Pet"
                    }
                },
                "type": "object",
                "required": [
                    "timestamp",
                    "data"
                ],
                "title": "PetNewEvent"
            },
            "ValidationError": {
                "properties": {
                    "loc": {
                        "items": {
                            "anyOf": [
                                {
                                    "type": "string"
                                },
                                {
                                    "type": "integer"
                                }
                            ]
                        },
                        "type": "array",
                        "title": "Location"
                    },
                    "msg": {
                        "type": "string",
                        "title": "Message"
                    },
                    "type": {
                        "type": "string",
                        "title": "Error Type"
                    }
                },
                "type": "object",
                "required": [
                    "loc",
                    "msg",
                    "type"
                ],
                "title": "ValidationError"
            }
        }
    }
}