I'm making a back-end for my app using Golang the app is for android,ios and windows and i'm trying to find a way to accept payments.
Is there a package that I can use with examples?
Like some of the comments have mentioned, I also suggest choosing a preferred payment system and then using a Go client library which interfaces with that payment system's REST API.
Here are a few payment libraries: https://golanglibs.com/top?q=payment Most of these include example files or examples in the readme. Many Go packages also use GoDoc for documentation.
The most popular one on the list there is PayPal-Go-SDK which is a Go client for the PayPal REST API. It includes an example file: https://github.com/logpacker/PayPal-Go-SDK/blob/master/example_test.go
It has GoDoc documentation: https://godoc.org/github.com/logpacker/PayPal-Go-SDK
If you prefer to use a different payment service like Stripe, they have a similar client: https://github.com/stripe/stripe-go
They also have usage examples: https://github.com/stripe/stripe-go#usage
They also have documentation: https://godoc.org/github.com/stripe/stripe-go