Senior Backend Engineer (Java)

About us

SMARTSEER—part of GIATA—turns first-party user behavior into real-time profiles and powers APIs for sorting, recommendations, and personalized incentives. Our clients configure and analyze everything in our self-serve DMP (management & analytics UI).

Why this role

Join a small, product-minded team where your decisions shape the platform. You’ll build and evolve Java services and selected TypeScript/Node components, define crisp API contracts, and explore new approaches that make our systems faster, clearer, and easier to extend.

What you'll do

• Build core services for user profiling, recommendations, sorting, and personalized incentives—clean APIs with well-defined SLIs/SLOs.
• Design clear contracts: OpenAPI-first endpoints, generated SDKs, and backward-compatible evolution (versioning, idempotency, pagination).
• Work across the data flow: ingest and transform first-party events, join product/category metadata, and expose real-time profile summaries to downstream models and APIs.
• Raise quality standards: meaningful tests (unit/integration/contract), performance baselines, and helpful observability (logs/metrics/traces).
• Collaborate across disciplines (Product/Design/AI): turn ambiguous ideas (e.g., “voucher selection for at-risk users”) into measurable increments.
• Evolve the stack where it adds value: runtime upgrades, build/test tooling, DX improvements, and pragmatic use of Node/TypeScript where it fits.

What makes you a great fit

• Strong Java fundamentals and experience delivering production services (HTTP APIs, concurrency, performance).
• Comfort with TypeScript/Node for service glue or dedicated endpoints where appropriate.
• API design skills: you think in contracts and trade-offs, and you document decisions clearly.
• Reliability mindset: testing strategy, graceful degradation, and sensible monitoring/alerts (daytime only—no on-call).
• Clear, friendly communication in a small, collaborative, English-speaking team.

Great things to add

• OpenAPI (generation/clients), contract testing, and API gateway patterns.
• Data stores you’ll meet here: MongoDB (plus exposure to Elasticsearch, Aerospike, Cassandra).
• Experience with model serving, feature stores, or data-rich products (analytics, recommendations, personalization).
• Performance work: profiling, caching, batching, pagination strategies.
• Tooling instincts: CI quality gates, build/test acceleration, monorepo patterns.
• Familiarity with common Java frameworks or equivalents; comfort reading/writing Node/Express where useful.
• Observability practice (logs/metrics/traces; Sentry or similar for error reporting).

Our stack (you'll touch some of this)

• Backend: Java services (Quarkus, Spring Boot); TypeScript/Node (Express) where it fits; OpenAPI-first contracts with generated clients.
• Core platform: Java & Python for data processing and ML.
• Storage: MongoDB; plus Elasticsearch, Aerospike, Cassandra.
• DevOps/Security: Azure DevOps (Ansible/Helm), Docker, Kubernetes on Azure (AKS), SonarCloud, Snyk; SSO via Google/Microsoft Entra ID.

Work style & location

• Hybrid, Frankfurt am Main — typically ~2–3 days/week together in the office.
• English-only in the office. No German required.
• No on-call / no out-of-hours support expectations.

What we offer

• Multicultural startup culture within an established travel-tech group (GIATA).
• Flat hierarchies, high trust, and real autonomy.
• Scope to shape architecture, tooling, and team practices.
• 30 days vacation.
• Modern tools (IntelliJ/WebStorm, sensible CI/CD).