Senior Full-Stack Engineer

About us Ruby Labs is a leading tech company that creates and operates innovative consumer products. We offer a diverse range of opportunities across the health, education, and entertainment industries. Our innovative teams are driving the future of consumer‑led products, and we're always looking for passionate individuals to join us. Learn more about our story at: About the role We’re looking for a Senior Full‑Stack Engineer to help build and scale a modern web platform using Next.js and Fastify. You’ll take ownership of complex features across the stack, contribute to architectural decisions, and ensure high standards for performance, security, and reliability. You’ll work closely with product and analytics teams to implement data‑driven improvements, integrate analytics, and run A/B tests that enhance the user experience. The role also involves researching and adopting new technologies, including AI‑driven solutions, to continuously improve both the product and development workflows. As a senior team member, you’ll mentor other engineers, promote best practices, and clearly communicate technical concepts to a wide range of stakeholders. This role is ideal for someone with a strong product mindset who enjoys building scalable, high‑quality systems end to end. Key Responsibilities FullStack Development: Take an active, hands‑on role in developing complex features and modules using Next.js for the frontend and NodeJS for the backend. Quality Assurance: Enforce best practices in coding, testing, caching, and performance monitoring to ensure a robust and scalable application. Security: Design and implement comprehensive security measures at the application, infrastructure, and data levels. Analytics & Optimization: Collaborate closely with the product team to integrate analytics systems and conduct A/B tests to enhance the user experience. Innovation: Research and integrate emerging technologies, particularly AI‑driven solutions, to improve the product and streamline development workflows. Qualifications Next.js: A minimum of 2 years of active, commercial experience with Next.js (v14.x/v15.x). Must have worked on at least two recent projects where Next.js was the primary frontend framework. NodeJS: Deep knowledge and at least 3 years of hands‑on experience with a modern framework such as NestJS, Fastify, or Hono. A clear understanding of their architectural trade‑offs is required. Databases: Strong proficiency with PostgreSQL and/or Supabase, including query optimization and schema design. ORM: In‑depth, practical knowledge of Prisma or Drizzle ORM, with experience in building complex queries and managing migrations. Caching: A profound understanding of caching strategies (e.g., in‑memory, distributed cache, CDN) and the ability to apply them effectively to optimize performance (e.g., using Redis). Docker: Full proficiency with Docker for creating, managing, and deploying containerized applications. Experience with docker‑compose is essential. Workers & Queues: Understanding and practical application of background workers and message queues (e.g., BullMQ, RabbitMQ) for handling asynchronous tasks. Security: Proven experience in building secure systems, including protecting against common vulnerabilities (OWASP Top 10), configuring Content Security Policy (CSP), CORS, securing APIs, and hardening hosting environments. Analytics & A/B Testing: Experience working with analytics tools (e.g., Google Analytics, PostHog, Mixpanel) and platforms for A/B testing. Mentorship: A genuine passion for teaching, sharing knowledge, and helping team members grow professionally. Communication: Excellent communication skills, with the ability to articulate complex technical concepts clearly to both technical and non‑technical stakeholders. Product Mindset: The ability to understand business objectives and translate them into technical solutions that deliver real value to users. Nice to have Experience with CI/CD pipelines (e.g., GitHub Actions, GitLab CI). Experience with monorepo tools (e.g., Turborepo, Nx). Experience writing unit and integration tests (e.g., Jest, Playwright). Location Ruby Labs operates within the CET (Central European Time) zone. Applicants from any country are welcome to apply for the position as long as they are located within approximately ± 4 hours of CET. This ensures optimal collaboration and communication during working hours. Benefits Discover the perks of being part of our vibrant team We offer: Remote Work Environment: Embrace the freedom to work from anywhere, anytime, promoting a healthy work‑life balance. Unlimited PTO: Enjoy unlimited paid time off to recharge and prioritize your well‑being, without counting days. Paid National Holidays: Celebrate and relax on national holidays with paid time off to unwind and recharge. Company‑provided MacBook: Experience seamless productivity with top‑notch Apple MacBooks provided to all employees who need them. Flexible Independent Contractor Agreement: Unlock the benefits of flexibility, autonomy, and entrepreneurial opportunities. Benefit from tax advantages, networking opportunities, reduced employment obligations, and the freedom to work from anywhere. Read more about it here: Be part of our fast‑growing team and seize this excellent opportunity for personal and professional growth Interview Process After submitting your application, we conduct a thorough review which typically takes 3 to 5 days, but may occasionally take longer due to the volume of applications received. If we see a potential fit, we proceed with the following steps: Recruiter Screening (40 minutes) Technical Interview (60 minutes) Final Interview (30 minutes) Life at Ruby Labs At Ruby Labs, we move fast, aim high, and expect the same from our team. We’re not here to play small—we’re here to build, grow, and win. That means we look for people who are ambitious, driven, and ready to give their best every single day. This is a place for individuals who thrive under pressure, embrace challenges, and see opportunity in every obstacle. If you’re hungry to achieve, motivated by impact, and want to grow at the speed of your own ambition, Ruby Labs offers the platform to make it happen. Here, effort is matched with reward. We recognize those who go all in and deliver results, and we create space for people who want more—more responsibility, more growth, and more success. #LI-Remote #J-18808-Ljbffr