A US AI startup building developer infrastructure for LLM-powered applications is hiring a Senior Backend Engineer to design and build the core API platform. You will work with a small, senior engineering team to deliver the services that developers rely on to build and deploy AI applications at scale. Role & Responsibilities: • Design and build high-performance REST APIs using Python and FastAPI, serving millions of requests per day • Architect microservices for AI workload orchestration: job queuing, async processing, result streaming and webhook delivery • Build robust data persistence layers using PostgreSQL and Azure Cosmos DB for structured and unstructured data • Implement authentication, authorisation and API key management using Azure Entra External ID and JWT patterns • Design for scale: caching with Redis, rate limiting, circuit breakers and graceful degradation under load • Build CI/CD pipelines and containerise services using Docker and Azure Container Apps • Write comprehensive unit, integration and load tests — you take reliability as seriously as features • Contribute to API design decisions, technical RFCs and engineering standards Required Skills & Experience: • 5+ years of backend engineering experience with strong Python expertise • Deep FastAPI knowledge — you have built and operated production FastAPI services, not just tutorials • PostgreSQL proficiency: schema design, query optimisation, indexing and connection pooling • Experience with async Python: asyncio, background tasks and streaming responses • Azure cloud experience: Functions, Container Apps, Cosmos DB, Service Bus, Key Vault • Familiarity with Docker and containerised deployment patterns • Understanding of LLM APIs (OpenAI, Anthropic) and streaming response patterns is a strong advantage What We Offer: • Fully remote role, open worldwide — US/EU/India time zones preferred • Salary $100,000–$130,000 USD based on experience and location • Equity in an early-stage company with strong traction and investor backing • Small team, high ownership, direct impact on the core product For a backend engineer who wants to build the infrastructure layer of an AI product from the ground up — with genuine ownership and without layers of process.
Remote · Worldwide | $100,000–$130,000