We’re hiring a senior engineer to build and harden a domain platform with a robust Django API backend, a deterministic validation/computation layer, and a React/TypeScript web workbench for complex multi-step workflows.

This is careful product engineering, not CRUD. You’ll move between a strictly layered backend and a modern frontend, and you’ll treat correctness, traceability, and user trust as product features.

What you’ll do

- Design and implement backend services in a well-layered Django architecture: models, domain rules, mutations, read models, and thin API views.

- Work on workflows where data can be drafted, reviewed, edited, validated, and explained.

- Extend validation and computation logic where results must be reproducible, testable, and easy to reason about.

- Build frontend workbench flows that make complex data tasks clear, fast, and safe for users.

- Own end-to-end correctness: data model → API contract → UI behavior → automated verification.

- Handle edge cases around permissions, retries, partial failures, stale data, conflicts, and auditability.

- Work from structured specs and produce small, reviewable changes.

Must-haves

- Senior-level production experience with Python/Django.

- Strong React + TypeScript experience.

- Strong PostgreSQL and Django ORM experience: modeling, migrations, constraints, query performance.

- Contract-first API discipline: OpenAPI, generated client types, stable API shapes, and no internal DB IDs in public contracts.

- Experience with correctness-critical backend patterns: transactions, expected-version / optimistic concurrency, idempotency, authorization, and audit trails.

- Strong testing reflex across the stack: pytest, frontend component tests, request mocking, and meaningful regression tests.

- Ability to understand an existing architecture before changing it.

- Strong domain modeling instinct: you know which logic belongs in models, services, policies, read models, API serializers, or UI components.

Must‑haves

• 5+ years shipping production software in Python/Django and React/TypeScript.
• Strong PostgreSQL + Django ORM (modeling, migrations, query/perf).
• Contract‑first discipline: OpenAPI, generated client types, API versioning, no internal DB ids in public contracts.
• Integrity patterns: optimistic concurrency (expected‑version), idempotency, audit trails, authorization done right.
• A real testing reflex across the stack: pytest, Vitest, end‑to‑end (Playwright), request mocking (MSW) — and you check contract drift before you call it done.
• Domain modeling instinct — you choose the right layer, not the convenient one.

Strong pluses

• Numerical / scientific computing (NumPy/SciPy), reproducibility, floating‑point precision.
• Geospatial (PostGIS), or desktop packaging (Tauri/Electron).
• Experience working spec‑first (spec → plan → tasks → code) with small, reviewable diffs.