Senior Fullstack Engineer – SaaS, Hybrid London

Firstup is seeking a Senior Full Stack Engineer to design and deliver large-scale, multi-tenant cloud services with a relentless focus on availability and elegant architecture. You will own features end-to-end across the frontend, backend, and data layers while mentoring peers and elevating engineering quality.

You’ll champion shift-left testing, integrate AI-assisted tooling, and collaborate closely with Product and Design to translate requirements into intuitive user interfaces.