I need to add PayPal button on client's website. It is first time I am doing this and I asked for credentials he gave me API signature, API username and API password. I was checking lots of tutorials how to add PayPal button, they use sandbox/live Client ID and Secret. Can I use this API credentials instead?
I searched a lot but couldn't find an answer. I am coding in CodeIgniter 3.
Thanks
Username, Password, and Signature are related to Classic API integration.
Client ID and Secret are related to the REST API integration.
Which one do you want to work with?
Or, the easiest option is to use PayPal Standard Payment Buttons, but that will also be the most limiting.
We actually have a PayPal CodeIgniter Library that you might be interested in. It was built for the Classic API.
The general PayPal PHP SDK that it's based on is now available with Composer, so I would recommend installing it that way.
We'll be releasing an update to that library before the end of the year that adds all of the REST APIs. It's available in the dev branch on GitHub already.