About Gapstars
At Gapstars, we partner with some of Europe's most ambitious companies, from disruptive tech startups to established Benelux accounting firms, helping them build high-performing teams in engineering and finance.
Headquartered in the Netherlands, with talent hubs in Sri Lanka and Portugal, we are home to 300+ professionals who thrive on solving real-world challenges with modern solutions. Our teams work across domains, from networking, marketplaces, SaaS, and AI to embedded finance and accounting, delivering scalable solutions that drive meaningful outcomes.
Job Overview
At Gapstars, our goal is to fuel growth for highly ambitious tech companies with world-class tech talent. We are looking for a Senior Full Stack Developer with a keen interest in the development of modern web platforms, as well as the ambition for personal growth and innovation. As part of a cross-functional team, you’ll be taking a lead on some of the most important and core parts of our platform. The ideal candidate will have extensive experience in building large-scale SaaS applications, leading development teams, and implementing best practices in code quality, security, and scalability.
Key Responsibilities
Develop and maintain high-performance web applications using React.js, Node.js, and MongoDB (or other NoSQL Databases)
Design and implement scalable, maintainable, and reusable front-end and back-end components
Architect, develop, and optimize RESTful APIs and backend services
Implement authentication and security mechanisms (JWT, OAuth) to protect application data
Work closely with UI/UX designers to create intuitive and visually appealing user interfaces
Optimize application performance by implementing best practices
Lead and mentor junior developers, conduct code reviews, and enforce coding standards
Conduct Unit Testing and Integration Testing using Jest to ensure software reliability
Work in an Agile/Scrum environment, collaborating with cross-functional teams to deliver high-quality products on schedule
Lead and contribute to the entire software development life-cycle, from ideation and planning to implementation, testing, deployment, and maintenance
Refactor and optimize existing code base to improve performance, reliability, and maintainability
Take ownership of key modules or components, ensuring their stability, security, and seamless integration with the overall system
Collaborate closely with cross-functional teams (product, design, and other engineering teams) to translate requirements into technical solutions
Technical Skills
Expertise in React.js and its core principles (Hooks, Context API, Component Lifecycle) and Node.js (Express.js, RESTful APIs, WebSockets, Authentication, Performance Optimization, Asynchronous Programming, Database Integration – NoSQL)
Strong knowledge of JavaScript (ES6+), TypeScript, and modern front-end development techniques
Proficiency in Redux (or Context API) for state management
Strong UI/UX understanding, experience with styled-components
Experience in writing custom hooks and reusable components
Deep understanding of RESTful APIs and their design principles
Expertise in authentication and security implementation (JWT, OAuth)
Expertise in MongoDB (Schema design, Aggregation, Indexing, Projection)
Experience in Unit Testing & Integration Testing (Jest)
Writing clean, maintainable, and scalable code following SOLID principles
Familiarity with Linting tools (ESLint, Prettier) and static code analysis
Experience & Qualifications
6+ years of professional experience in React.js and Node.js
Experience in designing and architecture of scalable, maintainable, and high-performance systems for fulfilling product requirements
Proven experience working on complex SaaS large-scale applications
Familiarity with Agile/Scrum methodologies
Soft Skills
Excellent problem-solving and debugging skills
Strong communication and leadership skills
Ability to work in a fast-paced environment
Strong analytical and decision-making skills
Bonus Skills (Optional)
Experience with AI/ML implementation
Experience working with mobile app development (React Native)
Hands-on experience with Serverless frameworks (AWS Lambda, Firebase Functions)
Perks & Benefits
We believe taking care of our people is non-negotiable. Here's what being a Star means:
