I am looking for an experienced VoIP/PBX developer to create a complete VoIP calling system from scratch and integrate it into my existing Django-based CRM. The goal is to enable users to make and receive calls directly from the CRM interface using a secure and reliable VoIP solution. Requirements: Setup of VoIP or PBX system (Asterisk, FreePBX, or any suitable open-source solution) SIP trunk configuration for call routing WebRTC or softphone integration for browser-based calling Call functionalities: outbound & inbound calling, call logs, call recordings, status tracking Route incoming calls to CRM as well as to a physical phone number (e.g., mobile or landline) User authentication and role-based access control for call features API endpoints to interact with Django backend (or direct integration) Basic dashboard/reporting for call activities Documentation for system setup and deployment Preferred Tech Stack: Asterisk / FreePBX / FusionPBX / FreeSWITCH (open to recommendations) WebRTC / SIP.js or similar for browser calling Additional Notes: Should be scalable and secure Clean and maintainable code Deployment on my VPS or cloud server Open to suggestions and best practices from the developer