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.