Can´t use Fetch in my extension

[BarryCarlyon]

This suggests you are in hosted test and the CSP is being applied.

And thus the API Link is not in the CSP rules for your extension.

See

• docs Extensions | Twitch Developers
• blog post Twitch Extensions Part 6 – Dev Environment Updates – Content Security Policy! – Barry Carlyon
• forum post New Extensions policy for Content Security Policy (CSP) directives and timeline for enforcement