Sr. Backend Developer

We are looking for a hands-on Senior Back-end Developer who writes production-grade server-side code. You will design and build the services and data layer behind our applications using Python, with relational databases underneath, all deployed and operated on AWS. This is a builder's role, not a coordinator's. You should be comfortable writing complex SQL by hand, designing REST APIs that other teams depend on, reasoning about performance and failure, and owning your code through testing, deployment, and production support.

Responsibilities:

• Design, build, and maintain Python (Flask/FastAPI) services and REST APIs consumed by our front ends and partners.
• Write and optimize advanced SQL multi-table joins, subqueries, CTEs, and window functions without leaning on an ORM to think for you.
• Model and evolve relational schemas, design indexes, and tune slow queries using EXPLAIN / EXPLAIN ANALYZE.
• Plan and run schema migrations safely against live data.
• Handle authentication, authorization, and the security of the endpoints you expose.
• Build background jobs, queues, and scheduled work, and make them safe to retry.
• Write meaningful unit and integration tests for the code and modules you ship.
• Deploy, monitor, and troubleshoot services on AWS, and improve build and release pipelines.
• Review peers' code, uphold quality standards, and mentor less experienced developers.

Requirements:

• This is a senior back-end role; we expect depth in Python and in relational databases, and the ability to run what you build.
• 5+ years of relevant, hands-on back-end development experience.
• Solid Python backend experience building REST APIs (Flask or FastAPI), not just scripting.
• SQL ability to write advanced queries from scratch and reason about how they execute in PostgreSQL and/or MySQL in production.
• Schema design, indexing, and query optimization on real data volumes.
• AWS practical experience deploying and running workloads (e. g., ECS/Fargate, Lambda, RDS).
• API security authentication and authorization (JWT, OAuth2) and common OWASP risks.
• Testing able to write proper unit and integration tests with pytest.
• Comfort with Git workflows, Docker, and CI/CD pipelines.

Nice to Have:

• Async Python (asyncio) and an understanding of concurrency trade-offs.
• Queues and background processing (Celery, SQS, or Kafka).
• Caching strategies with Redis and knowing when not to cache.
• Infrastructure as code (Terraform or AWS CDK).
• Observability: structured logging, metrics, tracing, and useful alerts.
• NoSQL stores (MongoDB, DynamoDB) alongside relational databases.
• Enough front-end familiarity (Angular or React) to debug an integration end-to-end.