Sr. Software Engineer, Fullstack (UK)

Team: Product Engineering

Location: Hybrid- London, UK

Commitment: Full-time

Workplace Type: hybrid

Job Summary

We're looking for a Senior Full Stack Engineer who thrives at the intersection of craft and scale. You'll design and deliver large-scale, multi-tenant cloud services — with a relentless focus on availability, fault-tolerance, and elegant architecture. You'll set the bar for engineering quality and help elevate those around you.

Responsibilities

Core Engineering & Ownership: Build and own scalable SaaS applications end-to-end — frontend, backend, and data layers. Write production-grade code that is reliable, readable, efficient, and testable. Raise the bar through thoughtful code reviews and comprehensive documentation.

System Architecture: Design future-ready architectures and proactively close gaps before they become problems.

Performance & Reliability: Drive system availability and performance — investigate, analyze, and resolve reliability issues across the stack. Recognize opportunities and advocate for better performance and efficiency of software, systems, and processes across teams.

Shift Left Testing & Quality: You champion a rigorous 'shift-left' quality culture, embedding comprehensive testing—unit, integration, and contract—early and continuously in the development lifecycle, not as an afterthought.

AI Integration: Leverage and advocate for AI-assisted tools (e.g., GitHub Copilot, Claude) to accelerate development while maintaining rigorous engineering judgment and accountability for code correctness.

Leadership: Drive team-wide best practices, conduct quality code reviews, and mentor engineers to elevate overall engineering quality.

Collaboration (Product & Design): Partner with Product and Design to translate requirements into intuitive UI, making informed technical trade-offs in the face of ambiguity.

Collaboration (Engineering Standards): Champion engineering best practices across teams and collaborate on solving complex, high-impact problems.

Minimum Qualifications

• Bachelor's degree in Computer Science or related field, or equivalent experience.

• 8+ years building reliable, performant applications and microservices in production environments. Proven full stack fluency - you're comfortable across frontend, backend, and the database layer. 

• A polyglot mindset — you evolve with the tech. Familiarity with Ruby on Rails, TypeScript, Node.js, Go, or React.js is a strong plus.

• Proven full-stack experience across frontend (React.js), backend, and database layers.

• Contribute to production health, including on-call rotations and incident response, in a "you build it, you run it" environment.

• Technical depth in at least one engineering domain: distributed systems, multi-tenant SaaS, application databases, networking, security, serverless, event streaming, or similar.

• A genuine drive to build beautiful, intuitive products with the customer always in focus. Innate curiosity — you love learning and have a desire to teach and lift others. Strong communication skills and openness to collaborative idea-sharing across teams.

Preferred Qualifications:

Core Stack Experience: Familiarity with Ruby (including Ruby on Rails), TypeScript, Node.js, Go, or React.js is a strong plus.