Senior Fullstack Developer - React, Typescript -80,000 - London

We're looking for a Senior/Principal Full-Stack Software Engineer to join our clients growing team. This is a high-impact role where you will shape our technical foundation, influence product direction, and help us scale. You'll work closely with cross-functional teams and leadership, including the CEO, to align long-term strategy, product vision, and user experience.

Key Responsibilities

• Drive the design and delivery of technical solutions that solve real business problems and create customer value
• Own key aspects of system architecture, ensuring scalability, security, and performance
• Collaborate with product, commercial, and leadership teams to balance user needs, technical constraints, and business priorities
• Write high-quality, maintainable code across the stack and contribute to code reviews
• Stay ahead of industry trends and bring best practices into the team

Requirements

Essential Experience

• 5+ years as a JavaScript/TypeScript engineer (full-stack)
• Proven experience in early-stage startup environments, ideally B2B SaaS
• Strong knowledge of modern frameworks (especially React)
• Experience building and maintaining APIs (REST/GraphQL), including documentation and SDKs
• Solid understanding of databases (SQL and NoSQL) and server-side development
• Experience deploying and managing applications on cloud platforms (AWS, Azure, or GCP)

What We're Looking For

• Ability to thrive in ambiguity, move fast, and take ownership
• Pragmatic approach to technology choices knowing when to keep things simple
• Strong communication and collaboration skills across disciplines
• Problem-solving mindset, comfortable making trade-offs to deliver value quickly without compromising long-term quality
• Leadership experience is a plus

Application Process

1. 15-minute screening call
2. Technical/architecture exercise (time-boxed)
3. 30-minute session with the tech team
4. Final interview with CEO