We are looking for a Principal Fullstack Developer(Node.js, React) with a passion for creative game design and systems engineering. You won’t just be pulling tickets from a backlog: you’ll be the technical authority for our products. You will lead two completely different engineering ecosystems: the highly optimized, memory-sensitive world of game clients and the backend infrastructure. You will bridge the gap between creative vision and technical reality, ensuring that the incredible experience enjoyed by players is powered by a robust, secure and scalable backend.

Main Responsibilities What You Will Do: E2E Game Architecture: Design, implement, and maintain complete game features. You will seamlessly integrate scalable server-side backend services with high-performance client-side gameplay and UI logic Decoupled Systems: Design a flexible, modular backend that efficiently serves data to various frontend game clients, ensuring seamless integration regardless of the client engine used Full-Stack Optimization: Balance performance across the entire product. Optimize server-side load management and database queries while simultaneously managing client-side memory and frame rate stability across a wide range of devices Unified Observability: Implement robust real-time data collection, logging, and crash reporting, to track the user journey from client-side actions to back-end server responses System Health & Proactive QA: Monitor the entire stack to swiftly detect, diagnose, and resolve cross-domain issues – whether they originate as client-side crashes or backend server bottlenecks Security & Risk Mitigation: Implement E2E security protocols for secure client-server communication. Protect sensitive user data on the server while deploying client-side risk mitigation, such as anti-cheat mechanisms and exploit prevention Act as the Technical Translator: Serve as the core bridge connecting UI/UX designers, Game Designers, and engineering leadership. You will help translate creative requirements into actionable code while ensuring the backend can support those designs Elevate the Team: Mentor developers in modern client-side and backend techniques, fostering a culture of high-quality code and technical ownership Set the Standard for Documentation: Create and maintain a unified knowledge base covering both sides of the stack – from API specs and server infrastructure to engine integration manuals Drive Agile alignment: Holistically scope features during sprints, ensuring technical requirements align with business goals while actively managing and reducing technical debt What to Expect: Strong Planning and prioritization: You will organize the plan so that you and the team can seamlessly shift gears from optimizing a memory allocation issue in the morning to designing a stateless architecture handling thousands of concurrent players in the afternoon Stakeholder management: You will work with product owners and game designers to translate their vision into technical reality, reviewing mechanics and proposing a viable, performant alternative Architecture engineering: You will marshal monitoring telemetry to ensure the servers stay up during massive traffic spikes and adjust the approach to facilitate high availability Product engineering: You will balance the demands of shipping features fast against the necessity of keeping the codebase clean, scalable, and modular

6+ years of development experience and 1+ year of leadership experience iGaming/Gambling experience will be a huge plus Proven Full-Stack Expertise: Deep professional experience in both game client development and scalable server-side backend architectures High Tolerance for Complexity: You are comfortable diving into ambiguous problems and designing systems from the ground up Proactive Problem Solver: You find and fix memory leaks, architecture flaws, or security vulnerabilities before they ever impact a player Exceptional Communicator: You can explain complex backend constraints to non-technical stakeholders and break down creative requirements into clear engineering tasks Experienced Leader: You have a track record of mentoring engineers, driving architectural decisions, and leading projects through the full software development lifecycle Fluent English + Ukrainian or Russian - must‑have (for communicaton with ukrainian teammates)

Stack: Languages: TypeScript, JavaScript (Node.js), React Frontend Graphics & Animation: WebGL rendering, 2D skeletal web animation Real-time Communication & Messaging: WebSockets, Event streaming brokers, Remote Procedure Calls Video Streaming: Ultra-low latency (sub-second) video streaming architecture utilizing WebRTC, WHIP, RTMP, and SRT for real-time ingest, combined with H5Live, Low-Latency HLS, MoQ, and ABR for global browser-based playback Databases & Storage: Relational (SQL), Document (NoSQL), In-memory caching, Columnar/Analytics databases Infrastructure & Orchestration: Cloud infrastructure, Containerization, Container orchestration Observability & Monitoring: Distributed telemetry, Log aggregation, Time-series monitoring dashboards

We offer Competitive Salary in EUR: with annual performance reviews to recognize your growth Flexible Remote Work: balance productivity and comfort Comprehensive Benefits: including medical insurance, psychologist support and Polish, Slovak speaking clubs Generous Paid Time Off: 20 working days of paid vacation, plus 10 additional paid days off, 10 paid sick days, and all national holidays in your country Professional Development Support: reimbursement for courses, trainings, and certifications Well-being Perks: support for language classes, sports, massages, or life coaching 6-Month Probation Period: a standard period to ensure a strong mutual fit for both you and the company