Build a user authentication and a payment gateway with paystack and Connect it with a web API

We are looking for an experienced developer that is familiar with web development, PHP, JavaScript and API integration. This job will entail building a web platform that authorizes users access, a payment system using Paystack both subscription and one time payment methods and also connecting the authorized users to a web platform through an API.

The Required Experience:
1. Familiar with JavaScript Programming language.
2. Experience in API development
3. Prior experience with User Authentication platforms (ie Google Firebase, Aws Cognito)
4. Experience in UI design and server side programming.