Senior Python/FastAPI Backend & FFmpeg Engineer for AI Video Generation SaaS

We are looking for a Senior Python/FastAPI Backend & FFmpeg Engineer to complete the video-generation backend of an existing AI SaaS platform. This is an AI-powered platform that allows users to generate short-form videos for TikTok, YouTube Shorts, and Reels. The website, infrastructure, authentication, user dashboard, admin dashboard, settings, credits system, payment gateway, AWS storage, and most core systems are already built. This project is not a new backend build. The task is to understand the existing codebase and complete the remaining video-generation features. This is not a project from scratch. Scope There are three video-generation niches: - Paper Quiz: Approximately 90% complete and already generates videos, but needs final fixes, testing, and stability improvements. - Quiz Video: Approximately 70% complete. The frontend is ready, and many features are shared with Paper Quiz. - Would You Rather: The frontend is ready, but the backend generation workflow must be built. Each niche also includes: - Step-by-Step video creation. - One-Click AI video generation. The selected engineer will complete these workflows, integrate them with the existing frontend, reuse shared backend services, and improve reliability. Technical Stack - Python and FastAPI - FFmpeg and video/audio processing - Celery and Redis for background job processing - PostgreSQL, SQLAlchemy, and Alembic - AWS S3 and CloudFront - External AI API integrations - REST APIs and asynchronous video-generation pipelines Don't apply if you don't have proven hands-on experience with FFmpeg and video-processing pipelines.