@iobroker/socketio-server

This package is used by WEB applications and adapters to communicate with ioBroker using websockets and the socket.io protocol.

Important Note: Since v4.0 of this package pure Websockets are used exclusively! Socket.io is no longer implemented by the socket.io library, but simulated via pure WebSockets!

Users can use this package to connect their products to ioBroker via web sockets. Actually, this package could be used by echarts, vis and many other adapters to extract data from ioBroker.

If possible, please use @iobroker/ws-server instead of this package.

By using of socket.io interface user should understand the basics and concept of the system.

It is useful to read about the structure of the objects too.

Brief description of concept

Object

Object is description of data point or group. The group could content other data points in this case it called channel. If a group consists of other channels, in this case it is called device.

Object is meta information that describes data point and could content: max/min value, unit, name, default value, type of value, information for adapter for communication (e.g., ip address) and so on.

State

State is the actual value of the data point and presented by javascript object:

const state = {
    val: VALUE, 
    ack: ACKNOWLEDGED, 
    ts: TIMESTAMP, // could be converted into time with "new Date(state.ts)" (In older version of js-controller - "new Date(state.ts * 1000)")
    lc: TIMESTAMP_of_last_change, 
    from: ADAPTER_NAME, 
    q: QUALITY
}

States change itself very frequently in compare to the objects. (Normally objects should be changed once by creation and that's all)

Acknowledgment

Every state has the attribute ack. It shows the direction of command.

• If ack=false, it means some other adapter wants to control (write) this variable, so that command will be executed (e.g., light will be switched on).
• If ack=true, it means that the device informs about new value. (e.g., light was switched on manually or motion was detected)

Example: we have some home automation adapter (HAA) that has one lamp connected under address haa.0.lamp1.

• Lamp can be switched on manually with physical switch or via Wi-Fi with the help of HAA.
• If vis wants to switch the lamp on via Wi-Fi, it should set the new value with {value: true, ack: false}.
• When the lamp is switched on it is normally informing HAA about new state and the value should be immediately overwritten with {value: true, ack: true}.
• If the lamp is switched off manually via physical switch it informs HAA about new state with {value: false, ack: true}.

Quality

Every data point has an attribute q - quality.

Usage

You can find the description of every supported method here.

It is suggested to use socket class for communication.

Tuning Web-Sockets

On some web-sockets clients, there is a performance problem with communication. Sometimes this issue is due to the fallback of socket.io communication on a long polling mechanism. You can set the option Force Web-Sockets to force using only web-sockets transport.

Changelog

8.0.5 (2026-06-20)

• (@GermanBluefox) Initial commit. Extracted from ioBroker.socketio adapter.
• (@GermanBluefox) A minimal Node.js version is 20

License

The MIT License (MIT)

Copyright (c) 2014-2026 @GermanBluefox [email protected]