If you ever fought, this might help.
Here’s a DEV write-up on a free world time API that needs no sign-ups or API keys, and it’s CORS-enabled.
Nice bits:
- Offsets + dst flag included
- IP-based timezone https://marvinffek254122.educationalimpactblog.com/60953220/no-signup-timezone-api-no-api-keys-for-frontend