Fullstack Engineer

Responsibilities

• Design, build, and maintain high-quality features across the full stack, from UI to API integration
• Write clean, well-tested, production-ready code and participate in active code reviews
• Collaborate with Product, Design, QA, and Backend teams to deliver user-centric features
• Integrate AI-powered coding agents and automated LLM-based testing into the daily development cycle
• Contribute to building 'AI-First' UI patterns and generative, prompt-driven interfaces
• Break down product requirements into actionable engineering tasks and deliver work within sprint commitments

Requirements

• 5+ years of professional Fullstack development experience with modern JavaScript/TypeScript
• Solid expertise in at least one major framework (React, Angular, or Vue) and its ecosystem
• Strong understanding of HTML5, CSS3, responsive design, and cross-browser compatibility
• Experience with state management patterns such as Redux, MobX, or Zustand
• Working knowledge of testing methodologies including unit, integration, and E2E (Jest, Cypress, or Playwright)
• Solid understanding of APIs, RESTful services, GraphQL, and system design fundamentals
• Experience using AI-assisted development tools (e.g., Claude Code, Cursor, or Copilot) to boost productivity
• A startup mindset with a bias for shipping, iteration, and navigating ambiguity

Preferred Qualifications

• Familiarity with ad-tech, real-time bidding platforms, or high-traffic data products
• Experience building Fullstack interfaces for AI/ML-powered products
• Familiarity with LLM APIs and prompt-driven UI patterns
• Contributions to open-source Fullstack projects

Benefits

• Flexible work-from-home arrangement
• $500 home-office setup budget
• $1,000 annual learning and development budget
• Exceptional career growth opportunities within a multinational team

About the Company

Kayzen is a mobile demand-side platform (DSP) dedicated to democratizing programmatic advertising. We enable leading apps, agencies, and brands to run programmatic customer acquisition and performance campaigns. Powering up to 1B+ ads per day across 180 countries, Kayzen is built on the pillars of performance, transparency, and control.