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Aatu HarjuAH

Aatu Harju

Senior Backend Engineer (Go)

€690/day
Helsingfors, FI
8-15 years

Average response time: 1 hour

About Aatu

Senior Backend Engineer specialising in Go (Golang) for SaaS teams. I build and harden REST APIs, data layers (PostgreSQL/MySQL) and integrations. I keep production calm: monitoring/alerts, dependency & security updates, and small reliability improvements every week.

Typical missions: API development, performance tuning, incident reduction, CI/CD, Docker, Kubernetes/GCP. Remote-only, Finland/EU time zones. If you need a part-time engineer or an ongoing caretaker retainer, send your stack + current pain and I'll propose the first 2-3 wins.
  • Finnish

    Native or bilingual

  • English

    Fluent

  • Spanish

    Basic

  • Swedish

    Basic

  • German

    Basic

Remote only
Primarily works remotely

Experience

  • Veikkaus Oy,
    Senior Software Developer
    DIGITAL AND IT
    January 2023 - Today (3 years and 5 months)
    Helsinki, Finland
    - Develop and maintain a production-critical Go (Golang) backend serving real-money players directly via REST APIs (high availability, low latency).
    - Deliver new backend capabilities and partner-facing integrations while keeping backwards compatibility and safe rollouts.
    - Build with a strong focus on security, robustness, and compliance expectations typical for regulated environments (secure coding, data protection, operational discipline).
    - Improve reliability through monitoring/alerts, incident reduction work, and pragmatic engineering hygiene (dependency updates, refactors that reduce risk).
    - Work on fair play mechanics and backend correctness: deterministic flows, auditability, and careful handling of game-critical logic.
    GO REST API PostgreSQL Google cloud
  • Mehiläinen Oy,
    Senior Software Developer
    DIGITAL AND IT
    January 2020 - January 2023 (3 years)
    Helsinki, Finland
    - Built a critical invoicing calculation system (backend + web UI) for healthcare staff, focusing on correctness, auditability, and maintainability.
    - Refactored and upgraded a legacy system with minimal downtime, improving reliability and making further changes safer.
    - Worked closely with stakeholders to translate complex domain rules into clear, testable logic; improved confidence via automated tests and careful rollout.
    - Integrated the solution into existing processes/systems (data flows, reporting/reconciliation), reducing manual work and operational friction.
    - Introduced and coached Scrum/agile practices in an org where agile was new (cadence, planning, delivery visibility), improving execution and alignment.
    PHP API PostgreSQL Google cloud Agile method
  • Quantum Shake Oy,
    Mobile Games Developer
    DIGITAL AND IT
    January 2015 - January 2020 (5 years)
    Oulu, Finland
    - Prototyped and developed mobile games in Unity3D from concept to playable builds; rapid iteration on core mechanics, UX, and feel.
    - Built a reusable mini-framework / tooling layer (project scaffolding, reusable components, build/iteration helpers) that reduced prototype cycles from weeks to days.
    - Hands-on across game design + client implementation, plus “just enough” backend/services work when needed (APIs, data persistence, integrations).
    - Operated Scrum ceremonies as Scrum Master (planning, refinement, retros), improving cadence and delivery clarity across the team.
    - Focused on maintainability and performance so prototypes stayed easy to extend instead of collapsing into throwaway spaghetti.
    Unity 3D Mobile development C# Scrum

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Education

  • Master's Degree in
    University of Oulu
    2015
    Master's Degree in
  • Bachelor's Degree
    University of Oulu
    2013
    Bachelor's Degree

Skill set

Categories