Web serial | Frontend Practical Guide

Overview

The navigator.serial API communicates with devices over serial ports, such as microcontrollers. It is most useful when native HTML semantics or browser capabilities can replace custom implementation work.

Browser support

Feature	Desktop				Mobile
Feature	Chrome	Edge	Firefox	Safari	Chrome Android	Safari iOS
`Serial` Experimental	89	89			138
`serial` Experimental The serial read-only property of the Navigator interface returns a Serial object which represents the entry point into the Web Serial API.	89	89			138
`getPorts` Experimental The getPorts() method of the Serial interface returns a Promise that resolves with an array of SerialPort objects representing serial ports connected to the host which the origin has permission to access.	89	89			138
`requestPort` Experimental The Serial.requestPort() method of the Serial interface presents the user with a dialog asking them to select a serial device to connect to. It returns a Promise that resolves with an instance of SerialPort representing the device chosen by the user.	89	89			138
`requestPort (allowedBluetoothServiceClassIds option)` Experimental `allowedBluetoothServiceClassIds` option	117	117			138
`requestPort (filters bluetoothServiceClassId)` Experimental `filters` `bluetoothServiceClassId` property	117	117			138
`SerialPort` Experimental The SerialPort interface of the Web Serial API provides access to a serial port on the host device.	89	89			138
`close` Experimental The SerialPort.close() method of the SerialPort interface returns a Promise that resolves when the port closes.	89	89			138
`connect_event` Experimental The connect event of the SerialPort interface is fired when the port connects to the device.	89	89			138
`connect_event (bluetooth rfcomm)` Experimental Bluetooth RFCOMM serial ports dispatch `connect` events	130	130			138
`connected` Experimental The connected read-only property of the SerialPort interface returns a boolean value that indicates whether the port is logically connected to the device.	130	130			138
`disconnect_event` Experimental The disconnect event of the SerialPort interface is fired when the port disconnects from the device.	89	89			138
`disconnect_event (bluetooth rfcomm)` Experimental Bluetooth RFCOMM serial ports dispatch `disconnect` events	130	130			138
`forget` Experimental The SerialPort.forget() method of the SerialPort interface returns a Promise that resolves when access to the serial port is revoked.	103	103			138
`getInfo` Experimental The getInfo() method of the SerialPort interface returns an object containing identifying information for the device available via the port.	89	89			138
`getInfo (bluetoothServiceClassId)` Experimental `bluetoothServiceClassId` return value property	117	117			138
`getSignals` Experimental The SerialPort.getSignals() method of the SerialPort interface returns a Promise that resolves with an object containing the current state of the port's control signals.	89	89			138
`open` Experimental The open() method of the SerialPort interface returns a Promise that resolves when the port is opened. By default the port is opened with 8 data bits, 1 stop bit and no parity checking. The baudRate parameter is required.	89	89			138
`readable` Experimental The readable read-only property of the SerialPort interface returns a ReadableStream for receiving data from the device connected to the port. Chunks read from this stream are instances of Uint8Array. This property is non-null as long as the port is open and has not encountered a fatal error.	89	89			138
`setSignals` Experimental The setSignals() method of the SerialPort interface sets control signals on the port and returns a Promise that resolves when they are set.	89	89			138
`writable` Experimental The writable read-only property of the SerialPort interface returns a WritableStream for sending data to the device connected to the port. Chunks written to this stream must be instances of ArrayBuffer, TypedArray, or DataView. This property is non-null as long as the port is open and has not encountered a fatal error.	89	89			138
`serial` Experimental The serial read-only property of the WorkerNavigator interface returns a Serial object which represents the entry point into the Web Serial API.	89	89			138
Other
`html.elements.iframe.allow.serial` Experimental	89	89			89
`http.headers.Permissions-Policy.serial` Experimental The HTTP Permissions-Policy header serial directive controls whether the current document is allowed to use the Web Serial API to communicate with serial devices, either directly connected via a serial port, or via USB or Bluetooth devices emulating a serial port.	89	89			89

1+Supported (version) Not supported ※Has note Sub-feature descriptions sourced from MDN Web Docs (CC BY-SA 2.5)

Syntax

JAVASCRIPT

const port = await navigator.serial.requestPort();
await port.open({ baudRate: 9600 });
const reader = port.readable.getReader();
const { value } = await reader.read();
console.log('Received:', new TextDecoder().decode(value));

Use cases

Use Web serial
Use Web serial when standard HTML needs a more specific platform feature, semantic signal, or browser capability.
Handle edge cases
Apply Web serial to solve a focused requirement without redesigning the whole page architecture.

Cautions

Test Web serial in your target browsers and input environments before depending on it as a primary behavior.
Provide a fallback path or acceptable degradation strategy when support is still limited.

Overview

Browser support

Syntax

Use cases

Use Web serial

Handle edge cases

Cautions

Accessibility

Related links