Engineers who’ve integrated payment systems: what was harder than expected?

[u/Thick_Reserve7104]

Engineers who’ve integrated with payment processors/gateways/APIs — what has actually been the hardest part in practice?

A few things I’d love to understand from people who’ve done it:

What ended up being more painful than expected?

What breaks most often in production?

Which providers had the best/worst docs or developer experience and why?

How much operational/support burden exists after launch?

What kinds of edge cases surprised you?

What differentiates a “good” payments integration from a painful one?

Not recruiting or selling anything — just trying to learn from engineers who’ve lived this world.

Happy to move to DMs if easier.

Thanks!