Swift로 Paypal, Facebook, Naver, WeChat 연동 구현
PayPal iOS SDK
https://github.com/paypal/PayPal-iOS-SDK
Braintree iOS SDK
https://github.com/braintree/braintree_ios
iOS용 Facebook 로그인 - 빠른 시작
https://developers.facebook.com/docs/facebook-login/ios
Facebook SDK for Swift
https://developers.facebook.com/docs/swift
https://github.com/facebook/facebook-sdk-swift
Naver ID Login SDK for iOS
https://github.com/naver/naveridlogin-sdk-ios
Getting Started on iOS (WeChat Open Platform)
http://open.wechat.com/cgi-bin/newreadtemplate?t=overseas_open/docs/mobile/getting-started/ios
How To Implement WeChat Login In iOS Swift
http://www.kekearif.com/how-to-implement-ios-wechat-login/
WeChat Login Android 연동
https://medium.com/@joongwon/wechat-login-android-%EC%97%B0%EB%8F%99-17d5c4f27614
Android WeChat Pay 개발하기
https://blog.kimkevin.net/android-dev-wechat-pay/
Instagram API —Authentication using Swift
https://wetalkit.xyz/instagram-api-authentication-using-swift-3bf27d7ed6aa
Manage Clients (Instagram Developer)
https://www.instagram.com/developer/clients/manage/
User Endpoints (Instagram Developer)