Back End Developer

About the role We are hiring a Senior Backend Engineer to own and evolve a Python-based Core API: a modular monolith built on FastAPI, async SQLAlchemy 2.0, Pydantic v2, and Alembic, running on a multi- tenant Postgres with row-level security. What you will own A FastAPI service using async SQLAlchemy 2.0, Pydantic v2 models, Alembic migrations, and strict typing ( mypy --strict ). Patterns across domain modules — setting the conventions that other engineers ship against.

State machines for core domain entities, including idempotent transitions and audit-grade event emission. RBAC enforcement on every state-mutating endpoint, idempotency keys, RFC 7807 error envelopes, and post-commit event publication. Faithful implementation of business rules across reporting and KPI surfaces.

Module-boundary discipline (enforced in CI via tools such as import-linter). Must-have 5+ years building Python backends in production. Deep on FastAPI, Pydantic v2, async SQLAlchemy 2.0 — async is the default, not an afterthought.

Strong PostgreSQL fluency: B-tree / GIN / expression / partial indexes, query plans, transaction semantics, advisory locks. Disciplined about correctness over cleverness: state machines, idempotency, audit trails. Comfortable reading unfamiliar code to derive business rules from existing behaviour.

Nice-to-have TimescaleDB hypertable / continuous-aggregate experience. Domain-driven design and explicit bounded-context modelling. Multi-tenant Postgres row-level security in production.

Experience working across two coexisting systems during a migration window.