Senior Backend Engineer — Java / Spring Boot

Studio Butterfly
Full-time•Tk 70k-100k/month (BDT)
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We're hiring a Senior Java / Spring Boot engineer to own the backend of a multi-tenant Membership Management platform for a European client. The backend is Java; the frontend is Flutter. You'll design clean, secure, well-tested modules — and set the standards the rest of the team follows.

This is a spec-driven, AI-native team: we develop with Claude Code. Your leverage comes from making the right architectural decisions, generating fast with the agent, and then rigorously reviewing every line before it ships to production.

What you'll do

  • Design and evolve the Spring Boot 3 backend — clean module boundaries, SPIs, and auto-configuration.

  • Own multi-tenancy security. Enforce strict tenant isolation across data, config, and credentials — you know the OWASP Multi-Tenant Security Cheat Sheet cold and apply it in every layer.

  • Integrate third-party APIs robustly — auth (Basic, API-key, request signing such as AWS SigV4), error mapping, retries, graceful failure.

  • Own persistence: JPA/Hibernate + Flyway migrations on PostgreSQL, tenant-scoped and PII-safe (masking, GDPR).

  • Drive development with Claude Code, then review its output critically — you are the quality backstop.

  • Practice Spec-Driven Development and build intensive automated tests (JUnit 5, Mockito, WireMock, Testcontainers) under an enforced coverage gate.

Requirements

  • At least 4 years of professional backend development experience (Java / Spring).

  • Senior-level Java 17+ and Spring Boot 3.x (auto-configuration, conditional beans, configuration properties).

  • Demonstrable multi-tenant SaaS experience and a real grasp of tenant-isolation threats.

  • JPA/Hibernate + migrations (Flyway/Liquibase) on PostgreSQL.

  • A deep test-automation habit — unit and integration tests by default; coverage is a floor, not a target.

  • Strong code-review skill — you spot subtle correctness, security, and design flaws in code you didn't write (including AI-generated code).

How we work — expected of every hire

  • Fluent with Claude Code for fast code generation — you move quickly with the agent, then manually review every change and take responsibility for what ships to the production server. AI writes the draft; you own the result.

  • Work independently — self-directed, comfortable owning ambiguity.

  • Take leadership — you own the project and lead it, setting standards rather than just following them.

  • Run multiple projects in parallel — context-switch cleanly while keeping quality high.

Nice-to-have

  • Reactive Spring (WebFlux / Project Reactor).

  • Low-level security work: HMAC signing, canonical requests, crypto without a vendor SDK.

  • GDPR / EU data-handling awareness.

  • Multi-module Maven monorepo experience.

Working arrangements

  • Location:

Hybrid — remote + office.

  • Office hours: 9:00 AM – 6:00 PM, including a 1-hour lunch break.

  • Working from home: attendance and working time are tracked via time-tracking software.

  • Employment: full-time.

Apply NowApply before: July 15, 2026