File System Access API

- UNOFF

API for manipulating files in the device's local file system (not in a sandbox).

Chrome

  1. 4 - 73: Not supported
  2. 74 - 85: Disabled by default
  3. 86 - 104: Partial support
  4. 105 - 141: Supported
  5. 142: Supported
  6. 143 - 145: Supported

Edge

  1. 12 - 18: Not supported
  2. 79 - 85: Disabled by default
  3. 86 - 104: Partial support
  4. 105 - 141: Supported
  5. 142: Supported

Safari

  1. 3.1 - 26.0: Not supported
  2. 26.1: Not supported
  3. 26.2 - TP: Not supported

Firefox

  1. 2 - 144: Not supported
  2. 145: Not supported
  3. 146 - 148: Not supported

Opera

  1. 9 - 60: Not supported
  2. 62 - 71: Disabled by default
  3. 72 - 90: Partial support
  4. 91 - 121: Supported
  5. 122: Supported

IE

  1. 5.5 - 10: Not supported
  2. 11: Not supported

Chrome for Android

  1. 142: Not supported

Safari on iOS

  1. 3.2 - 18.6: Not supported
  2. 26.0: Not supported
  3. 26.1: Not supported

Samsung Internet

  1. 4 - 28: Not supported
  2. 29: Not supported

Opera Mini

  1. all: Not supported

Opera Mobile

  1. 10 - 12.1: Not supported
  2. 80: Not supported

UC Browser for Android

  1. 15.5: Not supported

Android Browser

  1. 2.1 - 4.4.4: Not supported
  2. 142: Not supported

Firefox for Android

  1. 144: Not supported

QQ Browser

  1. 14.9: Not supported

Baidu Browser

  1. 13.52: Not supported

KaiOS Browser

  1. 2.5: Not supported
  2. 3: Not supported
Resources:
Chrome blog post
Explainer
Firefox position: harmful
Web.dev blog post