WebSocket Reference

Topics are used to receive real-time information from the robot. Use the following commands to start or stop listening to specific topics.

{"enable_topic": "TOPIC_NAME"}
{"disable_topic": "TOPIC_NAME"}

Since version 2.7.0, multiple topic names are supported. This requires the supportsEnableTopicList capability flag.

{"enable_topic": ["/actions", "/alerts", "/tracked_pose"]} // since 2.7.0
{"disable_topic": ["/actions", "/alerts", "/tracked_pose"]} // since 2.7.0

Protobuf Messages

Some topics are sent as binary protobuf WebSocket frames; others use JSON text messages. A connection can receive both formats. On servers that support it, append ?pb=1 to prefer protobuf for topics available in both formats.

Binary frames have this layout:

[topic_length: 1 byte][topic: UTF-8 bytes][flags: 1 byte][publisher_index: 1 byte, optional][payload]

The topic length is the number of bytes in the topic name. Flag bit 0 indicates a gzip-compressed payload; bit 1 indicates that the publisher index byte is present. Other flag bits are reserved. Decompress the payload when necessary, then decode it as ax_proto_msgs.RosMessageWrapper. Its type identifies the message, and the corresponding payload field contains the topic data.

The RosMessageWrapper definition lists the supported message types and payloads. The protobuf source directory contains their message definitions. These definitions are also available through the @kingsimba/axbot-sdk TypeScript SDK.

Topic index

Topics are grouped by function:

• Localization — SLAM state, pose, global positioning, barcodes, and landmarks.
• Mapping — map and costmap images, incremental updates, trajectory, and map-quality diagnostics.
• Navigation & Planning — planning state, paths, follow-target control, robot model, and signals.
• Chassis & Safety — wheels, odometry, IMU, bumper, and push handle.
• Cargo & Equipment — jack, roller, rack, pallet, and trailer state.
• Perception & Cameras — point clouds, detected objects, and camera streams.
• Environment & Connectivity — nearby robots, auto doors, V2X beacons, and GNSS/INS.
• System & Power — battery, sensor power, alerts, app events, and I/O pins.

Localization

Mapping

Navigation & Planning

Chassis & Safety

Cargo & Equipment

Perception & Cameras

Environment & Connectivity

System & Power