Senior Full Stack Developer (Backend Focus)

Job Role: Senior Full Stack Developer — Backend Focus (Python / FastAPI / PostgreSQL) Summary We’re hiring a Senior Full Stack Developer with a strong backend focus building and operating production-grade Python services. The ideal candidate has deep core Python knowledge (not just scripting), hands-on experience with FastAPI, production PostgreSQL, modern testing and dependency tooling, and practical frontend experience with React/Next.js. This role requires proven experience working on live systems for Banking domain. Key responsibilities (mapped to screening topics) · Design, build, and maintain backend services using Python and FastAPI for high-availability production systems. (maps to Core Python, FastAPI, Production systems) · Own API design and implementation, including OpenAPI specs, versioning, and backward compatibility. (maps to APIs) · Implement and maintain data models, schema migrations, indexing strategies, and query tuning in PostgreSQL. (maps to PostgreSQL experience) · Write comprehensive automated tests (unit, integration) and use pytest for test suites; maintain CI/CD test pipelines. (maps to pytest) · Manage dependencies and reproducible builds using tools like poetry and pip-tools. (maps to poetry, pip-tools) · Implement async patterns and concurrent processing where appropriate; understand GIL implications for concurrency decisions. (maps to asyncio, GIL) · Instrument, monitor, and troubleshoot production incidents; lead post-incident reviews and remediation. (maps to production incident experience) · Collaborate with frontend engineers to integrate React/Next.js UIs with Python backends; help define contracts and optimize client-server interactions. (maps to React/Next.js) · Perform performance tuning, caching, and optimization of services and DB queries. (maps to optimization examples) · Participate in architecture design, code reviews, and mentoring junior engineers. (maps to leadership/mentoring signals) Required qualifications · 5+ years professional software development experience, with at least 3 years working onsite (in-office or client-site) on development projects. · 4+ years of core Python development experience (not just scripting). · 2+ years hands-on experience building services with FastAPI (or equivalent modern ASGI frameworks). · 3+ years of production PostgreSQL experience, including schema design, indexing, migrations, and query tuning. · Strong familiarity with asyncio and concurrent patterns in Python; practical understanding of the GIL and implications for concurrency. · Experienced with pytest for unit/integration testing and CI pipelines. · Experience with dependency and packaging tools such as poetry and/or pip-tools; able to maintain reproducible environments. · Experience running ASGI servers (uvicorn/hypercorn) in production. · Frontend experience: 2+ years with React.js or Next.js and demonstrable examples of integrating JS frontends with Python backends (repo or demo links encouraged). · Able to describe at least one production incident you helped resolve and one concrete performance optimization you implemented. Preferred qualifications · Experience with Docker, Kubernetes, and cloud deployments (AWS/GCP/Azure). · Familiarity with observability tools (Prometheus, Grafana, Sentry, OpenTelemetry). · Experience with CI/CD (GitHub Actions, GitLab CI, Jenkins). · Experience maintaining mono-repos or multiple-service architectures. · Familiarity with security best practices for APIs and data protection. When you apply, you voluntarily consent to the disclosure, collection and use of your personal data for employment/recruitment and related purposes in accordance with the Tech Aalto Privacy Policy, a copy of which is published at Tech Aalto’s website (https://www.techaalto.com/privacy/) Confidentiality is assured, and only shortlisted candidates will be notified for interviews.