Best practices for handling payment payout workflows in web applications?

I’m currently researching how developers usually handle payment payout or cash-out related workflows in web applications.

I’ve noticed that some services provide very simple user-side flows, while others seem more complex regarding transaction timing, processing, and reliability.

I’m curious about a few things:

How do you typically structure payout-related workflows?

What’s the best way to handle async transaction states?

Are there common API integration patterns for third-party payment providers?

How do you manage reliability and response timing?

I’d appreciate insights from developers who have worked with similar payment or payout systems.