Senior Full-Stack Developer (Frontend Focus)

About the project:

We’re looking for a Senior Full-Stack Developer with a strong frontend focus to join our team on a project for a Dutch bookkeeping platform. The product is undergoing a major modernization of its accounting core: replacing legacy single-entry accounting logic with a database-backed double-entry model, improving ledger-code management, and introducing reconciliation capabilities.

The existing platform stays fully operational throughout, so all changes are delivered safely within the current architecture, in close collaboration with the client’s internal engineering team. This is a full-time engagement for approximately 19–23 weeks (Phases 3–4).

This is a frontend-focused role: React and production MobX experience are the core of the job, while Java/Spring knowledge helps you deliver features end to end.

Your team:

You’ll join an established Techstack team and work closely with the client’s internal engineers. The team includes a Project Manager, Lead Software Engineer, QA Engineer, Senior Full-Stack Developer (this position), 2 Back-End Developers, plus the client’s Solution Architect and CTO. We work through daily stand-ups, bi-weekly demos, regular code reviews, and close communication with the client’s developers.

Culture:

We 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.

Technical stack:

• Frontend: React, MobX, TypeScript, JavaScript

• Backend: Java, Spring, Hibernate, JPA, Redis

• Database: MariaDB, Flyway

• Testing: API/Cucumber, JUnit 5, WireMock, frontend/browser testing

• CI/CD & hosting: SonarCloud, CI pipelines, Docker, Linux, WAR deployment, AWS S3

• Tools: Jira, Confluence, Miro, Slack, Figma

• Practices: feature flags, code reviews, small PRs, regular releases

Your responsibilities:

• Develop and maintain features in existing React/MobX applications used by clients and bookkeepers

• Build administrative and configuration interfaces for ledger management and accounting workflows

• Implement searchable lists, forms with validation, role-based permissions, and reconciliation views

• Integrate frontend functionality with existing Java/Spring back-end APIs

• Support back-end development when needed for end-to-end delivery

• Make sure changes do not disrupt existing functionality in the live production platform

• Write and maintain frontend and browser-level automated tests

• Deliver changes through focused pull requests, feature flags, and regular releases

• Collaborate with the Tech Lead, back-end developers, QA, PM, and the client’s engineering team

• Participate in code reviews, daily stand-ups, demos, and acceptance testing

It’s about you:

• Strong commercial experience with React, TypeScript, and JavaScript

• Hands-on production experience with MobX

• Working knowledge of Java and Spring for end-to-end feature development

• Experience building admin/configuration interfaces, searchable lists, forms with validation, and role-based access

• Experience working with large existing codebases and maintaining backward compatibility

• Experience with feature flags, CI/CD, and small, focused pull requests

• Experience writing frontend and browser-level tests

• Ability to follow established architecture guidelines and collaborate through the client’s code reviews

• Good spoken and written English for daily communication with the client; Dutch is not required

• Time zone: Europe/Kyiv or compatible with CET/CEST working hours

Would be a plus:

• Experience in accounting, bookkeeping, or FinTech

• Experience with MariaDB, Hibernate, and Flyway

• Experience working with European clients

What we can offer you:

• Full-time engagement (40h/week) on a product with a complex, high-integrity domain

• Direct communication with all stakeholders, including the client’s engineering team

• Broad opportunities for professional and career growth: challenges, meetups, hackathons, professional communities, and more

• Horizontal connections and no micromanagement: all team members are accessible to each other for any questions

• Hubs in Kharkiv, Kyiv, Lviv, and Wrocław (Poland), or everything necessary for remote work

• Up to 50% compensation for educational courses and conferences

• Free English and business English courses

• 20 days off and 7 sick days

• Legal and accounting support

• Appreciation gifts for significant events and occasions

How to join Techstack:

1. Pre-screening with a Talent Acquisition Specialist

2. English check

3. Technical interview and evaluation with Techstack engineers

4. Candidate profile submission to the client

5. Technical interview with the client’s engineering representatives (if requested)