Python Backend Developer – FastAPI + AI (Remote/Flexible)

Backend for a my app using FastAPI, WebSockets/WebRTC, and modern AI services (Whisper STT, LLaMA-style LLMs, Kokoro/Coqui/Piper TTS, Wav2Lip for avatar video). The system powers realtime speech transcription, AI-assisted text polishing, and interactive avatar-based conversations.

Responsibilities
Backend ownership: Design, maintain, and extend FastAPI HTTP + WebSocket/WebRTC endpoints.
AI integration: Connect and optimize Whisper STT, LLMs, and TTS services for low latency and high reliability.
Audio/video pipelines:
Handle streaming audio (buffering, resampling, normalization).
Integrate avatar video generation with Wav2Lip and related tools.
Data & performance
Work with MongoDB (and/or relational databases) for schemas, indexing, and efficient queries.
Implement caching and background jobs to keep p95 latency within strict targets.
Reliability & quality:
Improve error handling, observability (logging/metrics), and tracing.
Write clean, well-structured, and testable Python code.

Must‑Have Skills
Async I/O and concurrency: Comfortable designing and debugging async workflows.
Hands‑on AI integration experience with at least one of:
Whisper STT or other speech‑to‑text engines.
LLaMA/transformer‑based LLMs or OpenAI‑style APIs.
TTS systems such as Coqui, Kokoro, or Piper.
Realtime systems: WebSockets, WebRTC, or other low‑latency streaming architectures.

Nice to Have
GPU & deployment experience:
CUDA, GPU environments, and performance tuning (CPU vs GPU).
Docker, nginx, PM2, and production deployment pipelines.
Background processing:
Job queues/workers for heavy audio/video processing.
Experience orchestrating long‑running media/AI tasks.
Video processing tools:
FFmpeg, Wav2Lip, or similar for video generation and post‑processing.