node.js developer in high-load platforms

CoreStar is a dynamic technology company supporting partners in heavy-load industries with high-performance solutions. Its teams focus on innovation, collaboration, and efficiency while developing impactful products.

• Develop scalable backend systems for high-load applications;
• Build RESTful services, GraphQL APIs, and real-time WebSocket connections;
• Optimize application performance through bottleneck identification, caching strategies, and resource utilization;
• Design and implement integrations with external APIs, payment systems, and service providers;
• Participate in the full development lifecycle from architecture design through deployment and monitoring;
• Use AI agents as part of daily engineering work;
• Contribute reusable AI skills, commands, automation, and workflows for the team;
• Automate repetitive engineering work;
• Write clean, well-documented code following best practices and design patterns;
• Monitor and troubleshoot production systems;
• Investigate complex issues and optimize database queries;
• Collaborate with product managers, designers, and other developers;
• Learn and evaluate new tools, frameworks, and best practices in the Node.js ecosystem.

• 5+ Years of professional software development experience focused on backend systems;
• 4+ Years of hands-on Node.js development in production environments;
• Deep understanding of JavaScript runtime internals;
• 3+ Years of experience with high-load systems and high-availability requirements;
• Proven experience with application scaling, database optimization, and system architecture;
• Advanced JavaScript and TypeScript proficiency;
• Deep knowledge of the Node.js ecosystem, event loop, and performance optimization;
• Experience with RESTful services, GraphQL, WebSocket connections, and third-party API integrations;
• Experience with MySQL, MongoDB, Redis / Valkey, query optimization, indexing, and schema design;
• Experience with NATS or Apache Kafka and distributed, event-driven architectures;
• Experience with Prometheus, Grafana, and ELK stack;
• Experience with Docker and Kubernetes;
• Experience with AWS or Azure, auto-scaling, load balancing, and distributed systems;
• Hands-on experience with agentic development tools such as Claude Code or equivalent;
• Experience creating reusable AI skills, commands, agent workflows, or MCP integrations;
• Ability to verify model output before acting on it;
• Strong English communication skills for technical discussions and complex documentation;
• Strong understanding of scalability, caching, and optimization techniques;
• Ability to debug complex distributed systems and design solutions for challenging technical problems;
• Ability to adapt engineering workflows as AI tooling changes.

• 24 Working days of paid annual leave;
• 6 Days of paid sick leave;
• Official employment;
• Medical insurance;
• Coffee zone with fruit and snacks available in the office;
• Corporate lunch provided by the company;
• Gym and sports classes;
• Healthy and friendly work atmosphere;
• Greek and English language classes partially covered.