_Haystack is working with a direct employer on this opportunity._ Senior Full Stack Engineer (Frontend-focused) Location: London (Hybrid – 3 days/week in office) Type: Full-time We’re hiring an exceptional Senior Software Engineer to help shape the future of our client’s platform. The client’s brief: You’ll play a key role in building intuitive, scalable, and high-performing features across our product. Whether your strength is in crafting elegant UI experiences or architecting robust backend systems, we’re looking for engineers who thrive in cross-functional teams and love owning features end-to-end. What You’ll Do - Deliver impactful features across the stack, with a focus aligned to your expertise (frontend or backend). - Own systems from architecture and implementation to deployment and ongoing improvement. - Collaborate closely with design, product, and customer teams to translate ideas into polished user experiences. - Contribute to the evolution of our technical direction, engineering practices, and product strategy. - Participate in the full development lifecycle: planning, coding, reviewing, launching, and iterating. What We’re Looking For - 5+ years’ experience building and shipping full stack applications. - Deep experience with React and TypeScript, strong UI/UX sensibilities, and a portfolio that showcases your frontend work. - Strong experience building scalable APIs and backend systems, ideally using Python (or a willingness to learn it). - Solid understanding of cloud infrastructure (AWS, GCP, or Azure). - Comfortable working in fast-paced, collaborative environments. - Bonus: Experience in a high-growth startup, familiarity with testing tools (e.g., Playwright, Storybook), and serverless architecture. Tech Stack - Frontend: React, TypeScript, Playwright, Storybook - Backend: Python, FastAPI, Postgres, TypeScript - Cloud: AWS (Lambda, DynamoDB, EKS, etc.) - DevOps & Tooling: GitHub Actions, Terraform, Docker