Can I use
?

Base64 encoding and decoding

- LS

Utility functions for of encoding and decoding strings to and from base 64: window.atob() and window.btoa().

IE

  1. 5.5 - 9: Not supported
  2. 10: Supported
  3. 11: Supported

Edge

  1. 12 - 86: Supported
  2. 87: Supported

Firefox

  1. 2 - 82: Supported
  2. 83: Supported
  3. 84 - 85: Supported

Chrome

  1. 4 - 86: Supported
  2. 87: Supported
  3. 88 - 90: Supported

Safari

  1. 3.1 - 13.1: Supported
  2. 14: Supported
  3. TP: Supported

Opera

  1. 9 - 10.1: Not supported
  2. 10.5: Support unknown
  3. 10.6 - 71: Supported
  4. 72: Supported

iOS Safari

  1. 3.2 - 13.7: Supported
  2. 14: Supported

Opera Mini

  1. all: Supported

Android Browser

  1. 2.1 - 4.4.4: Supported
  2. 81: Supported

Blackberry Browser

  1. 7: Supported
  2. 10: Supported

Opera Mobile

  1. 10: Support unknown
  2. 11 - 12.1: Supported
  3. 59: Supported

Chrome for Android

  1. 86: Supported

Firefox for Android

  1. 82: Supported

IE Mobile

  1. 10: Supported
  2. 11: Supported

UC Browser for Android

  1. 12.12: Supported

Samsung Internet

  1. 4 - 11.2: Supported
  2. 12.0: Supported

QQ Browser

  1. 10.4: Supported

Baidu Browser

  1. 7.12: Supported

KaiOS Browser

  1. 2.5: Supported
Resources:
MDN Web Docs - atob()
MDN Web Docs - btoa()
Polyfill