Can I use
?

Web Sockets

- LS

Bidirectional communication technology for web apps

Chrome

  1. ◐ 4 - 14: Partial support
  2. ◐ 15: Partial support
  3. ✅ 16 - 130: Supported
  4. ✅ 131: Supported
  5. ✅ 132 - 134: Supported

Edge

  1. ✅ 12 - 130: Supported
  2. ✅ 131: Supported

Safari

  1. ❌ 3.1 - 4: Not supported
  2. ◐ 5 - 5.1: Partial support
  3. ◐ 6 - 6.1: Partial support
  4. ✅ 7 - 18.0: Supported
  5. ✅ 18.1: Supported
  6. ✅ 18.2 - TP: Supported

Firefox

  1. ❌ 2 - 3.6: Not supported
  2. ◐ 4 - 5: Partial support
  3. ◐ 6 - 10: Partial support
  4. ✅ 11 - 131: Supported
  5. ✅ 132: Supported
  6. ✅ 133 - 135: Supported

Opera

  1. ❌ 9 - 10.6: Not supported
  2. ◐ 11 - 12: Partial support
  3. ✅ 12.1 - 113: Supported
  4. ✅ 114: Supported

IE

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

Chrome for Android

  1. ✅ 131: Supported

Safari on iOS

  1. ❌ 3.2 - 4.1: Not supported
  2. ◐ 4.2 - 5.1: Partial support
  3. ✅ 6 - 18.0: Supported
  4. ✅ 18.1: Supported
  5. ✅ 18.2: Supported

Samsung Internet

  1. ✅ 4 - 25: Supported
  2. ✅ 26: Supported

Opera Mini

  1. ❌ all: Not supported

Opera Mobile

  1. ❌ 10: Not supported
  2. ◐ 11 - 12: Partial support
  3. ✅ 12.1: Supported
  4. ✅ 80: Supported

UC Browser for Android

  1. ✅ 15.5: Supported

Android Browser

  1. ❌ 2.1 - 4.3: Not supported
  2. ✅ 4.4 - 4.4.4: Supported
  3. ✅ 131: Supported

Firefox for Android

  1. ✅ 132: Supported

QQ Browser

  1. ✅ 14.9: Supported

Baidu Browser

  1. ✅ 13.52: Supported

KaiOS Browser

  1. ✅ 2.5: Supported
  2. ✅ 3: Supported

Reported to be supported in some Android 4.x browsers, including Sony Xperia S, Sony TX and HTC.

Resources:
Details on newer protocol
MDN Web Docs - WebSockets API
Wikipedia
has.js test
WebPlatform Docs