Full Stack JavaScript Developer (Node.js / React)

Full Stack JavaScript Developer (Node.js / React) About CRIF CRIF is an international company providing credit and business information services, data processing, and advanced decisioning solutions. We support financial institutions, insurers, utilities, and enterprises with reliable data, analytics, and secure, scalable technology platforms.WBO (White Blue Ocean) is CRIF’s personal and cyber security division focused on advanced monitoring of the Open and Dark Web. Using AI and machine learning, it identifies leaked, stolen, or exposed data and delivers proactive alerts for individuals and companies. Role Overview We are looking for an experienced Full Stack JavaScript Developer to join the WBO team and help build a complex data processing and analytics platform, covering backend services, frontend applications, and large-scale data pipelines. Key Responsibilities • Design, develop, and maintain scalable backend services using Node.js • Build modern, responsive web applications with React • Develop and maintain RESTful APIs and microservices • Implement and optimize data processing pipelines (ETL, streaming) • Design and optimize PostgreSQL databases and complex queries • Implement authentication and authorization mechanisms (JWT, ACL) • Optimize application performance and data processing efficiency • Write and maintain unit and integration tests • Participate in code reviews and ensure high code quality • Deploy and maintain applications in an AWS cloud environment • Troubleshoot production issues and implement sustainable solutions • Collaborate with the team on architecture and technical decisions • Document technical solutions and API specifications Required Skills & Experience • Strong experience with Node.js (v22+) and Express.js • Solid knowledge of React (v16+) • Experience with PostgreSQL and query optimization • Very good understanding of asynchronous JavaScript (async/await, Promises) • Experience designing scalable RESTful APIs • Knowledge of microservices and distributed systems • Familiarity with testing frameworks (Jest, Mocha) • Experience working with Git and modern build tools (Webpack / Rollup) • Understanding of web security best practices • Basic knowledge of AWS and cloud architecture concepts Nice to Have • Experience with AWS Lambda, S3, Athena, CloudWatch • Docker and CI/CD pipelines (e.g. Jenkins) • TypeScript, Redis, Bull, Socket.io • Python or Rust for performance-critical components • Experience working with and modernizing legacy systems What We Offer • Employment contract • Hybrid work model (50/50 – office in Kraków) • Work on large-scale, data-driven systems in an international environment • Real impact on system architecture and technology decisions • Modern tech stack and strong engineering culture • Cooperation with experienced and supportive teams • Competitive salary aligned with your experience (salary range will be shared during the first interview)