Uint8Array base64 and hex conversionBaseline · Newly available

The Uint8Array.fromBase64() static method and the toBase64() and setFromBase64() instance methods convert to and from base64 strings. Similarly, the Uint8Array.fromHex() static method and the toHex() and setFromHex() instance methods convert to and from hex strings.

Works in the latest version of every major browser, but older devices may not support it yet. Baseline since Sep 5, 2025.

How to use ↓Compare browsers

Browser support

DesktopChrome

1–139Not supported

140+Supportedsince Sep 2, 2025

Current: 155

Edge

12–139Not supported

140+Supportedsince Sep 5, 2025

Current: 154

Firefox

1–132Not supported

133+Supportedsince Nov 26, 2024

Current: 157

Safari

1–18.1Not supported

18.2+Supportedsince Dec 11, 2024

Current: 27

MobileChrome Android

18–139Not supported

140+Supportedsince Sep 2, 2025

Current: 155

Firefox Android

4–132Not supported

133+Supportedsince Nov 26, 2024

Current: 157

Safari iOS

1–18.1Not supported

18.2+Supportedsince Dec 11, 2024

Current: 27

How to use

Every current browser supports this, but it only became Baseline on Sep 5, 2025. Use it as a progressive enhancement, or keep a fallback if you support older devices.

Example

Full syntax and examples are on MDN: fromBase64.

Feature detection

JS · check before using

if ("fromBase64" in Uint8Array || ("prototype" in Uint8Array && "fromBase64" in Uint8Array.prototype)) {
  // Uint8Array.fromBase64 is available
}

Documentation (MDN)

Specification

Sub-features

Support for each part of the feature (6). The overall table above shows when the whole feature works.

Sub-feature	Chrome	Edge	Firefox	Safari	Chrome Android	Firefox Android	Safari iOS
Uint8Array.fromBase64	140	140	133	18.2	140	133	18.2
Uint8Array.fromHex	140	140	133	18.2	140	133	18.2
Uint8Array.setFromBase64	140	140	133	18.2	140	133	18.2
Uint8Array.setFromHex	140	140	133	18.2	140	133	18.2
Uint8Array.toBase64	140	140	133	18.2	140	133	18.2
Uint8Array.toHex	140	140	133	18.2	140	133	18.2