Python Chat Backend Implementation

I need a solid backend written in Python that powers one-on-one messaging for an existing mobile chat application. The core tasks are to expose clean REST and WebSocket endpoints, handle real-time delivery, persist messages reliably in PostgreSQL, and keep latency low under moderate load... (Budget: ₹12500 - ₹37500 INR, Jobs: Django, Docker, FastAPI, Flask, JavaScript, PostgreSQL, Python, REST API, Software Architecture)