Need an experienced php developer

We seek a highly skilled PHP developer to expand our live tracking capabilities. The selected freelancer will integrate our system with Firebase to implement real-time notifications and updates. The developer must have extensive experience building APIs for live data synchronization between client and server systems. Some key responsibilities include utilizing Firebase's webhook functionality to forward device registration tokens to our backend, allowing the publication of notifications to specific devices or segments of users. The developer will also implement logic in our backend APIs to manage subscriber lists for different notification types and handle responding to requests from the Firebase console. Strong knowledge of JSON, REST APIs, and frontend-backend integration is required. Candidates must demonstrate past experience architecting similar real-time syncing solutions between mobile and web applications. Proficiency with PHP 7+, MySQL, and JavaScript/Node.js is mandatory. US-based freelancers are preferred for better communication and collaboration.