As the sole backend engineer on an AI SaaS platform, I built a unified API gateway that brings together 100+ generative models from multiple providers. I designed it around a shared core, a FastAPI application, and an independent worker process.
I built provider failover that pins the selected route when generation starts, and tracks model health from platform failure data. For reliability, I added RabbitMQ dead letter queues, circuit breakers, and retry handling that separates transient from terminal failures.
I built the platform’s transactional billing ledger with idempotent writes, auditable running balances, and dynamic per-model pricing. I also implemented retrieval with PostgreSQL and pgvector, plus production agents that use tools and manage conversation context.
In freelance and contract projects, I built and maintained Telegram bots and a B2B messaging assistant using Instagram and WhatsApp Business APIs. I also built a pipeline that turns scanned logistics documents into spreadsheet records, and delivered Docker deployments while working with clients from requirements through production.
