asyncapi.json

{
  "asyncapi": "2.6.0",
  "info": {
    "title": "X-Plane Local Web API — WebSocket",
    "version": "3.0.0",
    "description": "WebSocket interface for the X-Plane local web server. Use this to subscribe to real-time dataref updates (10Hz), stream dataref writes, and control commands.\n\nThe WebSocket endpoint shares the same TCP port as the REST API. All messages are JSON strings.\n\nEvery client message must include a unique `req_id` (numeric, non-recyclable). Each message you send must have a new, never-before-used `req_id`. The server responds with a `result` message containing the same `req_id` so you can match responses to requests. If the operation type is not recognized, the server returns the `unknown_type` error code.\n\nFor more information, see the [official documentation](https://developer.x-plane.com/article/x-plane-web-api/).",
    "contact": {
      "name": "X-Plane Developer",
      "url": "https://developer.x-plane.com"
    }
  },
  "servers": {
    "local": {
      "url": "localhost:8086/api/v3",
      "protocol": "ws",
      "description": "X-Plane local WebSocket server (default port). Change port with `--web_server_port=XXXX` when launching X-Plane."
    }
  },
  "channels": {
    "/": {
      "publish": {
        "operationId": "sendMessage",
        "summary": "Messages sent from client to X-Plane",
        "description": "All client-to-server messages. Each message must include a unique `req_id` and a `type` field.",
        "message": {
          "oneOf": [
            { "$ref": "#/components/messages/DatarefSubscribeValues" },
            { "$ref": "#/components/messages/DatarefUnsubscribeValues" },
            { "$ref": "#/components/messages/DatarefSetValues" },
            { "$ref": "#/components/messages/CommandSubscribeIsActive" },
            { "$ref": "#/components/messages/CommandUnsubscribeIsActive" },
            { "$ref": "#/components/messages/CommandSetIsActive" }
          ]
        }
      },
      "subscribe": {
        "operationId": "receiveMessage",
        "summary": "Messages received from X-Plane",
        "description": "All server-to-client messages including operation results and real-time updates.",
        "message": {
          "oneOf": [
            { "$ref": "#/components/messages/Result" },
            { "$ref": "#/components/messages/DatarefUpdateValues" },
            { "$ref": "#/components/messages/CommandUpdateIsActive" }
          ]
        }
      }
    }
  },
  "components": {
    "messages": {
      "DatarefSubscribeValues": {
        "name": "dataref_subscribe_values",
        "title": "Subscribe to dataref value updates",
        "summary": "Subscribe to periodic value updates for one or more datarefs (v1+). Updates are pushed at 10Hz, but only when values change. Possible error codes: `index_out_of_range`, `not_an_array`, `invalid_dataref_id`.",
        "payload": {
          "type": "object",
          "required": ["req_id", "type", "params"],
          "properties": {
            "req_id": {
              "$ref": "#/components/schemas/ReqId"
            },
            "type": {
              "type": "string",
              "const": "dataref_subscribe_values"
            },
            "params": {
              "type": "object",
              "required": ["datarefs"],
              "properties": {
                "datarefs": {
                  "type": "array",
                  "description": "List of datarefs to subscribe to",
                  "items": {
                    "type": "object",
                    "required": ["id"],
                    "properties": {
                      "id": {
                        "type": "integer",
                        "format": "int64",
                        "description": "Dataref ID"
                      },
                      "index": {
                        "description": "For array datarefs: a single index or array of indices to subscribe to",
                        "oneOf": [
                          { "type": "integer" },
                          {
                            "type": "array",
                            "items": { "type": "integer" }
                          }
                        ]
                      }
                    }
                  }
                }
              }
            }
          }
        },
        "examples": [
          {
            "name": "subscribe_example",
            "summary": "Subscribe to multiple datarefs with index selection",
            "payload": {
              "req_id": 9998,
              "type": "dataref_subscribe_values",
              "params": {
                "datarefs": [
                  { "id": 1223, "index": 2 },
                  { "id": 1224, "index": [0, 1, 2, 3] },
                  { "id": 1225 }
                ]
              }
            }
          }
        ]
      },
      "DatarefUnsubscribeValues": {
        "name": "dataref_unsubscribe_values",
        "title": "Unsubscribe from dataref value updates",
        "summary": "Stop receiving updates for one or more datarefs (v1+). The operation is idempotent. Use `\"all\"` to unsubscribe from everything. Possible error codes: `index_out_of_range`, `not_an_array`, `invalid_dataref_id`.",
        "payload": {
          "type": "object",
          "required": ["req_id", "type", "params"],
          "properties": {
            "req_id": {
              "$ref": "#/components/schemas/ReqId"
            },
            "type": {
              "type": "string",
              "const": "dataref_unsubscribe_values"
            },
            "params": {
              "type": "object",
              "required": ["datarefs"],
              "properties": {
                "datarefs": {
                  "description": "List of datarefs to unsubscribe from, or the string `\"all\"` to unsubscribe from everything",
                  "oneOf": [
                    {
                      "type": "array",
                      "items": {
                        "type": "object",
                        "required": ["id"],
                        "properties": {
                          "id": {
                            "type": "integer",
                            "format": "int64",
                            "description": "Dataref ID"
                          },
                          "index": {
                            "description": "For array datarefs: a single index or array of indices to unsubscribe from",
                            "oneOf": [
                              { "type": "integer" },
                              {
                                "type": "array",
                                "items": { "type": "integer" }
                              }
                            ]
                          }
                        }
                      }
                    },
                    {
                      "type": "string",
                      "const": "all"
                    }
                  ]
                }
              }
            }
          }
        },
        "examples": [
          {
            "name": "unsubscribe_specific",
            "summary": "Unsubscribe from specific datarefs",
            "payload": {
              "req_id": 1234,
              "type": "dataref_unsubscribe_values",
              "params": {
                "datarefs": [
                  { "id": 1223, "index": 2 },
                  { "id": 1225 }
                ]
              }
            }
          },
          {
            "name": "unsubscribe_all",
            "summary": "Unsubscribe from all datarefs",
            "payload": {
              "req_id": 1235,
              "type": "dataref_unsubscribe_values",
              "params": {
                "datarefs": "all"
              }
            }
          }
        ]
      },
      "DatarefSetValues": {
        "name": "dataref_set_values",
        "title": "Set dataref values",
        "summary": "Set one or more dataref values via WebSocket (v1+). For array datarefs, you can set a specific index or the whole array. Possible error codes: `index_out_of_range`, `not_an_array`, `insufficient_data`, `invalid_dataref_id`.",
        "payload": {
          "type": "object",
          "required": ["req_id", "type", "params"],
          "properties": {
            "req_id": {
              "$ref": "#/components/schemas/ReqId"
            },
            "type": {
              "type": "string",
              "const": "dataref_set_values"
            },
            "params": {
              "type": "object",
              "required": ["datarefs"],
              "properties": {
                "datarefs": {
                  "type": "array",
                  "description": "List of datarefs to set",
                  "items": {
                    "type": "object",
                    "required": ["id", "value"],
                    "properties": {
                      "id": {
                        "type": "integer",
                        "format": "int64",
                        "description": "Dataref ID"
                      },
                      "value": {
                        "description": "Value to set: a number, array of numbers, or base64 string",
                        "oneOf": [
                          { "type": "number" },
                          {
                            "type": "array",
                            "items": { "type": "number" }
                          },
                          { "type": "string" }
                        ]
                      },
                      "index": {
                        "type": "integer",
                        "description": "For array datarefs: specific index to set"
                      }
                    }
                  }
                }
              }
            }
          }
        },
        "examples": [
          {
            "name": "set_values_example",
            "payload": {
              "req_id": 1234,
              "type": "dataref_set_values",
              "params": {
                "datarefs": [
                  { "id": 88491, "value": 6 },
                  { "id": 39222, "value": [2, 2, 1, 0] },
                  { "id": 37555, "value": 2, "index": 1 }
                ]
              }
            }
          }
        ]
      },
      "CommandSubscribeIsActive": {
        "name": "command_subscribe_is_active",
        "title": "Subscribe to command activation updates",
        "summary": "Subscribe to activation status updates for one or more commands (v2+). Updates are pushed when command status changes. Possible error codes: `invalid_command_id`.",
        "payload": {
          "type": "object",
          "required": ["req_id", "type", "params"],
          "properties": {
            "req_id": {
              "$ref": "#/components/schemas/ReqId"
            },
            "type": {
              "type": "string",
              "const": "command_subscribe_is_active"
            },
            "params": {
              "type": "object",
              "required": ["commands"],
              "properties": {
                "commands": {
                  "type": "array",
                  "description": "List of commands to subscribe to",
                  "items": {
                    "type": "object",
                    "required": ["id"],
                    "properties": {
                      "id": {
                        "type": "integer",
                        "description": "Command ID"
                      }
                    }
                  }
                }
              }
            }
          }
        },
        "examples": [
          {
            "name": "subscribe_commands",
            "payload": {
              "req_id": 9998,
              "type": "command_subscribe_is_active",
              "params": {
                "commands": [
                  { "id": 1223 },
                  { "id": 1224 },
                  { "id": 1225 }
                ]
              }
            }
          }
        ]
      },
      "CommandUnsubscribeIsActive": {
        "name": "command_unsubscribe_is_active",
        "title": "Unsubscribe from command activation updates",
        "summary": "Stop receiving activation updates for one or more commands (v2+). Use `\"all\"` to unsubscribe from everything. Possible error codes: `invalid_command_id`.",
        "payload": {
          "type": "object",
          "required": ["req_id", "type", "params"],
          "properties": {
            "req_id": {
              "$ref": "#/components/schemas/ReqId"
            },
            "type": {
              "type": "string",
              "const": "command_unsubscribe_is_active"
            },
            "params": {
              "type": "object",
              "required": ["commands"],
              "properties": {
                "commands": {
                  "description": "List of commands to unsubscribe from, or `\"all\"`",
                  "oneOf": [
                    {
                      "type": "array",
                      "items": {
                        "type": "object",
                        "required": ["id"],
                        "properties": {
                          "id": {
                            "type": "integer",
                            "description": "Command ID"
                          }
                        }
                      }
                    },
                    {
                      "type": "string",
                      "const": "all"
                    }
                  ]
                }
              }
            }
          }
        },
        "examples": [
          {
            "name": "unsubscribe_commands",
            "payload": {
              "req_id": 1234,
              "type": "command_unsubscribe_is_active",
              "params": {
                "commands": [
                  { "id": 1223 },
                  { "id": 1224 }
                ]
              }
            }
          }
        ]
      },
      "CommandSetIsActive": {
        "name": "command_set_is_active",
        "title": "Set command active state",
        "summary": "Activate or deactivate one or more commands (v2+). Optionally set a duration after which the command auto-deactivates. If disconnected, all commands are automatically released. Possible error codes: `invalid_command_id`, `duration_out_of_range`.",
        "payload": {
          "type": "object",
          "required": ["req_id", "type", "params"],
          "properties": {
            "req_id": {
              "$ref": "#/components/schemas/ReqId"
            },
            "type": {
              "type": "string",
              "const": "command_set_is_active"
            },
            "params": {
              "type": "object",
              "required": ["commands"],
              "properties": {
                "commands": {
                  "type": "array",
                  "description": "List of commands to activate or deactivate",
                  "items": {
                    "type": "object",
                    "required": ["id", "is_active"],
                    "properties": {
                      "id": {
                        "type": "integer",
                        "description": "Command ID"
                      },
                      "is_active": {
                        "type": "boolean",
                        "description": "Whether to activate (true) or deactivate (false) the command"
                      },
                      "duration": {
                        "type": "number",
                        "format": "float",
                        "minimum": 0,
                        "description": "Time in seconds after which the command auto-deactivates. Only valid when `is_active` is true. Omit to hold indefinitely (max 24 hours). Use 0 for immediate press-and-release."
                      }
                    }
                  }
                }
              }
            }
          }
        },
        "examples": [
          {
            "name": "set_active_example",
            "payload": {
              "req_id": 1234,
              "type": "command_set_is_active",
              "params": {
                "commands": [
                  { "id": 88491, "is_active": true, "duration": 0.5 },
                  { "id": 37555, "is_active": true, "duration": 0 },
                  { "id": 39222, "is_active": false }
                ]
              }
            }
          }
        ]
      },
      "Result": {
        "name": "result",
        "title": "Operation result",
        "summary": "Server response to any client request, indicating success or failure. If the operation type is not recognized, the server returns the `unknown_type` error code.",
        "payload": {
          "type": "object",
          "required": ["req_id", "type", "success"],
          "properties": {
            "req_id": {
              "$ref": "#/components/schemas/ReqId"
            },
            "type": {
              "type": "string",
              "const": "result"
            },
            "success": {
              "type": "boolean",
              "description": "Whether the operation succeeded"
            },
            "error_code": {
              "type": "string",
              "description": "Machine-readable error code (present when success is false)"
            },
            "error_message": {
              "type": "string",
              "description": "Human-readable error message (present when success is false)"
            }
          }
        },
        "examples": [
          {
            "name": "success",
            "summary": "Successful operation",
            "payload": {
              "req_id": 123,
              "type": "result",
              "success": true
            }
          },
          {
            "name": "error",
            "summary": "Failed operation",
            "payload": {
              "req_id": 123,
              "type": "result",
              "success": false,
              "error_code": "invalid_dataref_id",
              "error_message": "Dataref id 99999 doesn't exist"
            }
          },
          {
            "name": "unknown_type",
            "summary": "Unrecognized operation type",
            "payload": {
              "req_id": 124,
              "type": "result",
              "success": false,
              "error_code": "unknown_type"
            }
          }
        ]
      },
      "DatarefUpdateValues": {
        "name": "dataref_update_values",
        "title": "Dataref value updates",
        "summary": "Periodic updates pushed by the server at 10Hz after a successful subscription. Only contains datarefs whose values have changed since the last update.",
        "payload": {
          "type": "object",
          "required": ["type", "data"],
          "properties": {
            "type": {
              "type": "string",
              "const": "dataref_update_values"
            },
            "data": {
              "type": "object",
              "description": "Object with dataref IDs as keys and current values as values. Values are numbers for scalar datarefs or arrays for array datarefs.",
              "additionalProperties": {
                "oneOf": [
                  { "type": "number" },
                  {
                    "type": "array",
                    "items": { "type": "number" }
                  }
                ]
              }
            }
          }
        },
        "examples": [
          {
            "name": "update_example",
            "payload": {
              "type": "dataref_update_values",
              "data": {
                "88491": 0,
                "3994": 5,
                "199": [0, 0, 0, 4]
              }
            }
          }
        ]
      },
      "CommandUpdateIsActive": {
        "name": "command_update_is_active",
        "title": "Command activation updates",
        "summary": "Pushed by the server when subscribed commands change their activation status (v2+).",
        "payload": {
          "type": "object",
          "required": ["type", "data"],
          "properties": {
            "type": {
              "type": "string",
              "const": "command_update_is_active"
            },
            "data": {
              "type": "object",
              "description": "Object with command IDs as keys and activation status (boolean) as values",
              "additionalProperties": {
                "type": "boolean"
              }
            }
          }
        },
        "examples": [
          {
            "name": "command_update_example",
            "payload": {
              "type": "command_update_is_active",
              "data": {
                "88491": false,
                "3994": false,
                "199": true
              }
            }
          }
        ]
      }
    },
    "schemas": {
      "ReqId": {
        "type": "integer",
        "description": "Unique, non-recyclable numeric identifier for the request. Each message you send must have a new, never-before-used req_id. The server response will echo this ID back in the `result` message so you can match responses to requests."
      }
    }
  }
}