PHP api integration on Eventin Plugin

My project is looking for an experienced Freelancer to integrate a RESTful API into the Eventin Plugin. The integration should enable authentication for the plugin users to enable access to the plugin’s features. I already have an API key and credentials for the integration. I'm looking for a Freelancer to help with the integration so that it can be completed in a satisfactory manner. The integration should be able to perform authentication, data retrieval and data exchange, so the Freelancer will need to be experienced with those areas. The project should be completed to the highest possible standard and within allotted deadlines.