TheEncoding API enables web developers to work with text that is represented incharacter encodings systems other than the encoding used internally by JavaScript strings. In particular, it enables developers to convert text between JavaScript strings and theUTF-8 encoding that is used for most documents on the web.

It provides two mechanisms:

• Encoding: taking a JavaScript string and converting it into an array of bytes representing theUTF-8 encoding of the string.
• Decoding: taking an array of bytes representing a particular character encoding of some text, and converting it into a JavaScript string.

Note that these operations are asymmetrical: encoding only encodes to UTF-8, while decoding can decode UTF-8 but alsomany legacy encoding systems.

The API provides synchronous interfaces for encoding and decoding, and alsostream-based encoders and decoders, which could be used to, for example, decode text as it arrives over a network connection.

This page was last modified onJun 28, 2025 byMDN contributors.