{"id":4010558,"url":"https://alion.io/job/tech-stack-middle-java-software-engineer","title":"Middle Java Software Engineer","company":{"id":454527,"name":"Tech Stack","domain":"tech-stack.com","url":"https://alion.io/company/tech-stack-2","size_band":"11-50","is_staffing_agency":true,"employer_type":"agency","is_intermediary":false,"listed_via":null,"ats_vendor":null,"truth_index":null},"role":"Backend","role_family":"Backend","seniority":"middle","employment_type":"full_time","work_mode":"remote","remote_scope":"stated_countries","remote_scope_basis":"posting_text","remote_working_hours":{"label":"CET","utc_offset_min":1,"utc_offset_max":1},"hiring_geo_confidence":"inferred","locations":["Ukraine"],"countries":["UA"],"hiring_countries":["PL"],"hiring_countries_total":1,"salary":null,"salary_estimate":null,"experience_years_min":null,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"Confluence","optional":false},{"name":"Figma","optional":false},{"name":"Flyway","optional":false},{"name":"Hibernate","optional":false},{"name":"JavaScript","optional":false},{"name":"Jira","optional":false},{"name":"JUnit","optional":false},{"name":"Linux","optional":false},{"name":"MariaDB","optional":false},{"name":"Miro","optional":false},{"name":"MySQL","optional":false},{"name":"React.js","optional":false},{"name":"Slack","optional":false},{"name":"SQL","optional":false},{"name":"TypeScript","optional":false},{"name":"Amazon S3","optional":true},{"name":"AWS","optional":true},{"name":"Cucumber","optional":true},{"name":"Docker","optional":true},{"name":"Java","optional":true},{"name":"OpenAI","optional":true},{"name":"PostgreSQL","optional":true},{"name":"Redis","optional":true}],"status":"live","first_seen_at":"2026-11-10T09:07:49Z","employer_posted_date":null,"last_verified_at":"2026-11-10T09:07:49Z","board_verified":false,"closed_at":null,"days_open":0,"trust":{"level":"not_scored","repost_count":null,"flags":[],"days_open":0},"description":"Back-End Enginner (Java/Spring, Release & Operations Support) \n\nStart & timeline:\n\nWe’re hiring in advance. The project is currently in Phase 2, and the role starts with Phase 3, expected in early January 2027 (exact date TBC). We’ll keep you updated throughout the hiring process.\n\nAbout the project:\n\nWe’re looking for two Java Engineers (Middle+ / Senior level) to join our team on a project for a Dutch bookkeeping platform. The product is modernizing its accounting core: replacing legacy single-entry accounting logic with a database-backed double-entry model, improving ledger-code management, and introducing reliable reconciliation capabilities.\n\nAll changes are implemented within the existing Java/Spring application, with a strong focus on production stability, preserving historical accounting data, and safe migration to the new model. The current platform must keep running without disruption. This is a full-time engagement for approximately 19–23 weeks (Phases 3–4).\n\nYour team:\n\nYou’ll join an established Techstack engineering team and work closely with the client’s internal developers and technical stakeholders. The team includes a Project Manager, Lead Software Engineer, QA Engineer, Senior Full-Stack Developer, and 2 Back-End Developers (these positions), plus the client’s Solution Architect and CTO. We work through daily stand-ups, sprint reports, regular code reviews, and close collaboration with the client’s engineering team.\n\nCulture:\n\nWe uphold high standards in the tech industry and continuously evolve to meet them. Every team member can influence the product, the company, internal processes, and their own professional growth. We also regularly organize team-building activities to keep a friendly atmosphere and simply enjoy time together.\n\nTechnical stack:\n\nBackend: Java, Spring, Hibernate (monolith), JPA, Redis\n\nDatabase: MariaDB, PostgreSQL, Flyway migrations\n\nTesting & quality: JUnit 5, WireMock, API/Cucumber tests, CI, SonarCloud\n\nHosting & deployment: Linux, WAR deployment, Docker (local/CI), AWS S3\n\nIntegrations: third-party payroll and banking APIs, tax authority APIs, OpenAI, Mailgun\n\nDelivery practices: feature flags, regular releases, roll-forward fixes\n\nFrontend (awareness only): React, MobX, TypeScript, JavaScript\n\nTools: Jira, Confluence, Miro, Slack, Figma\n\nYour responsibilities:\n\nDevelop back-end functionality within the existing Java/Spring monolith: APIs, business logic, and data models\n\nDesign and modify database schemas; implement safe schema and data migrations\n\nImplement accounting logic with strong data-integrity requirements: balanced entries, auditability, and no data loss\n\nDevelop role-based access controls for new functionality\n\nBuild and maintain reconciliation and validation tools to compare the new accounting logic with existing system behavior\n\nWrite unit and integration tests and keep regression suites green\n\nSupport production releases: CI pipelines, feature flags, deployments, and post-release monitoring\n\nInvestigate application logs and help troubleshoot deployment and production issues\n\nWork closely with the Tech Lead, back-end and front-end developers, QA, PM, and the client’s engineering team\n\nParticipate in code reviews and maintain technical documentation\n\nIt’s about you:\n\nSolid commercial experience with Java\n\nHands-on production experience with Spring and Hibernate\n\nStrong SQL skills and relational database design, preferably MariaDB or MySQL\n\nExperience with schema and data migrations using Flyway or similar tools\n\nGood understanding of transactions, database constraints, data integrity, and idempotent operations\n\nExperience writing unit and integration tests (JUnit 5, WireMock, or similar)\n\nExperience maintaining and extending large existing codebases without breaking functionality\n\nFamiliarity with feature flags, small focused PRs, and CI pipelines\n\nComfortable working with Linux, application logs, and supporting production releases; hands-on experience with deployments, troubleshooting, and post-release monitoring is highly valued\n\nAbility to follow established architecture standards and collaborate through code reviews with the client’s developers\n\nGood spoken and written English for daily communication with the client\n\nTime zone: Europe/Kyiv or compatible with CET/CEST working hours\n\nWould be a plus:\n\nExperience in accounting, bookkeeping, or FinTech projects\n\nExperience with dual-write, reconciliation, or data verification during migrations and data model changes\n\nWhat we can offer you:\n\nFull-time engagement (40h/week) on a product with a complex, high-integrity domain\n\nDirect communication with all stakeholders, including the client’s engineering team\n\nBroad opportunities for professional and career growth: challenges, meetups, hackathons, professional communities, and more\n\nHorizontal connections and no micromanagement: all team members are accessible to each other for any questions\n\nHubs in Kharkiv, Kyiv, Lviv, and Wrocław (Poland), or everything necessary for remote work\n\nUp to 50% compensation for educational courses and conferences\n\nFree English and business English courses\n\n20 days off and 7 sick days\n\nLegal and accounting support\n\nAppreciation gifts for significant events and occasions\n\nHow to join Techstack:\n\nPre-screening with a Talent Acquisition Specialist\n\nEnglish check\n\nTechnical screening and evaluation with Techstack engineers\n\nCandidate profile submission to the 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