Full Stack Engineer / Technical Lead B2B SaaS

Company: Client Server
Apply for the Full Stack Engineer / Technical Lead B2B SaaS
Location: London
Job Description:

Overview

In this role you will own the technical strategy and architecture for developer ecosystems, driving API and SDK design to ensure usability and scale. You will lead cross-team initiatives to expand client libraries and guide open-source collaboration, while mentoring engineers and shaping product direction. The position blends hands-on development with leadership in a fast-growing, global real-time infrastructure context. Join a collaborative, customer-focused team that values pragmatic engineering and impactful tech decisions.

Pay / Benefits

  • EMI share option scheme
  • 28 days annual leave
  • Enhanced maternity and parental leave
  • Personal learning and development budget
  • BUPA Health Insurance + dental costs
  • Fully paid one month sabbatical at five years

Responsibilities

  • own the technical strategy and architecture for Developer Ecosystems (iOS, Web, Infra/Automation)
  • define and drive best practices for API and SDK design ensuring consistency and scalability
  • lead complex cross-team initiatives to expand client libraries
  • oversee the full development lifecycle from design to release and maintenance
  • mentor junior engineers and review contributions to raise the technical bar
  • guide external contributors and open-source collaboration
  • act as a key interface with the developer community and incorporate feedback into product direction

Key requirements

  • senior software engineer with experience building developer tooling and APIs
  • strong hands-on experience with Ruby, TypeScript and React
  • experience in product-focused B2B SaaS environments
  • ability to make technical decisions that drive projects and raise the bar
  • familiar with AI tools such as Claude and Cursor and their process-optimising potential
  • customer and product focused
  • collaborative and pragmatic with mentoring experience
  • solid understanding of CS fundamentals (OOP, data structures, design patterns)
  • collaborative
  • customer-focused
  • mentoring and coaching
  • Ruby
  • TypeScript
  • React

…

Posted: October 4th, 2026