Gumroad integration looks simple. Users buy a license key and you could verify the key via their API from your extension: https://help.gumroad.com/article/76-li

Gumroad integration looks simple. Users buy a license key and you could verify the key via their API from your extension: https://help.gumroad.com/article/76-license-keys https://help.gumroad.com/article/76-license-keys I'm using Paddle for my paid Chrome extension (https://www.checkbot.io/ https://www.checkbot.io/) but integration is more involved. Paddle and Gumroad also tax care of all country specific tax + VAT for you, unlike say Stripe, which saves a ton of hassle and paperwork if you're in the EU anyway.