If you want to power your web or mobile app with bitcoin and want to offer payments directly in the app, have a look at the Alby Wallet API. It allows native payment experiences for users. As a web developer, you can entirely focus on your app. Alby covers your back and does the payment processing for you.
Have a look at the Alby Wallet API documentation:
You can request invoices from your Alby lightning address and use Lightning Tools to verify whether a payment has been made in order to execute additional logic.
You can send payments using your personal Alby account using Nostr Wallet Connect or the LndHub API.