Full Stack JavaScript Developer (Node.js / React)

Full Stack JavaScript Developer (Node.js / React)About CRIFCRIF 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 OverviewWe 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 ResponsibilitiesDesign, develop, and maintain scalable backend services using Node.jsBuild modern, responsive web applications with ReactDevelop and maintain RESTful APIs and microservicesImplement and optimize data processing pipelines (ETL, streaming)Design and optimize PostgreSQL databases and complex queriesImplement authentication and authorization mechanisms (JWT, ACL)Optimize application performance and data processing efficiencyWrite and maintain unit and integration testsParticipate in code reviews and ensure high code qualityDeploy and maintain applications in an AWS cloud environmentTroubleshoot production issues and implement sustainable solutionsCollaborate with the team on architecture and technical decisionsDocument technical solutions and API specificationsRequired Skills & ExperienceStrong experience with Node.js (v22+) and Express.jsSolid knowledge of React (v16+)Experience with PostgreSQL and query optimizationVery good understanding of asynchronous JavaScript (async/await, Promises)Experience designing scalable RESTful APIsKnowledge of microservices and distributed systemsFamiliarity with testing frameworks (Jest, Mocha)Experience working with Git and modern build tools (Webpack / Rollup)Understanding of web security best practicesBasic knowledge of AWS and cloud architecture conceptsNice to HaveExperience with AWS Lambda, S3, Athena, CloudWatchDocker and CI/CD pipelines (e.g. Jenkins)TypeScript, Redis, Bull, Socket.ioPython or Rust for performance-critical componentsExperience working with and modernizing legacy systemsWhat We OfferEmployment contractHybrid work model (50/50 – office in Kraków)Work on large-scale, data-driven systems in an international environmentReal impact on system architecture and technology decisionsModern tech stack and strong engineering cultureCooperation with experienced and supportive teamsCompetitive salary aligned with your experience(salary range will be shared during the first interview)