Senior Full-stack Engineer (Remote)

Please note that we will never request payment or bank account information at any stage of the recruitment process. As we continue to grow our teams, we urge you to be cautious of fraudulent job postings or recruitment activities that misuse our company name and information. Please protect your personal information during any recruitment process. While Monks may contact potential candidates via LinkedIn, all applications must be submitted through our official website ( monks.com/careers ). We specialize in managing and maturing production web applications for our clients, and we seek engineers who thrive when owning a feature long after its initial launch. As a Senior Fullstack Engineer focused on stability and evolution, you will work across React / Next.js and Node / TypeScript to maintain, stabilize, and enhance features to ensure they remain reliable in production environments.= You will operate within a Monks delivery team, collaborating with clients and product stakeholders to take real ownership of the long-term health of a production-deployed solution. We are pioneers in agentic engineering for maintenance; you will use tools like Claude Code and Codex daily to refactor, optimize, and scale existing codebases. We are looking for individuals who are fluent in working alongside AI coding agents to guarantee the long-term stability and performance of established systems. Who You Are Comfortable across the whole stack: You can navigate and improve existing codebases without friction or loss of momentum. Stewardship-minded: You enjoy taking a live feature and moving it toward an optimized state, sweating the details of long-term care. A pragmatic approach: You prioritize robust solutions that improve performance and ensure the system holds up under sustained load. A clear communicator: You keep clients and teammates informed about system health and evolution without unnecessary noise. What You'll Do Maintain, optimize, and evolve features across the frontend (React / Next.js) and backend (Node / TypeScript). Refactor and scale APIs while optimizing the underlying data models to support growth. Review code and monitor production telemetry to ensure ongoing quality and consistency. Collaborate with product, design, and other engineers to ship refinements end-to-end. Troubleshoot and resolve production issues to maintain high availability. Contribute to the team's evolving standards, tooling, and maintenance practices. What You Bring 5+ years of experience maintaining and scaling high-traffic, full-stack web applications. Strong TypeScript proficiency, specifically in improving React/Next.js frontends and Node backends. Proven experience in API optimization and database performance tuning. Hands-on experience ensuring stability and scale on AWS. Disciplined testing habits and an eye for highly maintainable, readable code. Strong English communication skills for effective client and team collaboration. Comfort working in a fast-paced, agile consulting environment focused on delivery excellence. Extra Credit Experience working on AI-heavy products or integrating LLMs into existing workflows. Deep expertise in PostgreSQL optimization and management. Experience maintaining or expanding an established design system. Familiarity with CI/CD and DevOps practices to streamline production updates. Open-source contributions or maintenance work you are proud to share. About Monks Monks is the global, digital-first, data-driven, unitary operating brand of S4 Capital plc. With a legacy of innovation and specialized expertise, Monks combines an extraordinary range of global Marketing and Technology Services to redefine how brands interact with the world. Through Monks.Flow, its flagship AI ecosystem for marketing orchestration, Monks transforms marketing into a growth engine, collapsing timelines and connecting brands to culture in real time. By deploying bespoke intelligent agents across disciplines and delivering culturally relevant, high-impact creative and digital solutions, Monks solves key critical business challenges across the entire brand enterprise to help brands sustain long-term impact. Monks was named a Contender in The Forrester Wave™: Global Marketing Services, ranks among Cannes Lions' Top 10 Creative Companies (2022-25) and remains the only partner featured in AdExchanger’s Programmatic Power Players list every year (2020-24). Named Adweek’s first AI Agency of the Year (2023) and The One Show’s inaugural AI Pioneer Organization, Monks was also awarded Business Intelligence Group’s 2025 Excellence in Artificial Intelligence Award in both the Organizational and AI Product categories. As a trusted partner to cutting-edge innovators in tech, Monks earned titles such as Optimizely Experimentation Partner of the Year (2025), runner-up for the Adobe Firefly Partner Award (2024), and Workato’s AI Visionary Customer Impact Award (2024). Additionally, Monks achieved a record-breaking number of FWAs and continues to hold the most of any partner. We are an equal-opportunity employer committed to building a respectful and empowering work environment for all people to freely express themselves amongst colleagues who embrace diversity in all respects. Including fresh voices and unique points of view in all aspects of our business not only creates an environment where we can all grow and thrive but also increases our potential to produce work that better represents—and resonates with—the world around us.