Senior/Principal Full Stack Software Engineer

Alderson Ltd; Camden Town; Hybrid; GBP 150,000 - 200,000; Full time

Job summary

A fast-growing B2B SaaS company in Camden Town is seeking a Senior or Principal Full-Stack Software Engineer to help shape their platform's technical foundations. This role involves designing scalable systems, collaborating cross-functionally, and influencing product strategy. Ideal candidates will have over 5 years of experience in JavaScript and TypeScript, strong proficiency in React, and a background in cloud platforms. The position offers competitive salary, flexible working, and share options.

Benefits

Competitive salary

25 days holiday + bank holidays

Share options

Private healthcare

Flexible working options

Career development opportunities

Qualifications

• 5+ years of experience working with JavaScript/TypeScript as a full-stack engineer.
• Experience leading projects or teams in a technical capacity.
• Strong proficiency in modern front-end frameworks.

Responsibilities

• Design and implement scalable, secure, and high-performance systems.
• Own and evolve core parts of the platform architecture.
• Collaborate with product, commercial, and leadership teams.

Skills

JavaScript/TypeScript

React

SQL and NoSQL databases

API design (REST/GraphQL)

Cloud platforms (AWS, Azure, GCP)

Collaboration

Communication

Job description

Overview

We are working with an ambitious and well-funded early-stage B2B SaaS company building something transformative. They are hiring a Senior or Principal Full-Stack Software Engineer to help lay the technical foundations of their platform and influence engineering direction and long-term product strategy.

Responsibilities

• Design and implement scalable, secure, and high-performance systems.
• Own and evolve core parts of the platform architecture.
• Collaborate with product, commercial, and leadership teams to align technical delivery with strategic goals.
• Write clean, maintainable code across the full stack and contribute to reviews and debugging.
• Bring new ideas and best practices to continuously elevate engineering standards.

Qualifications

• 5+ years of experience working with JavaScript/TypeScript as a full-stack engineer.
• Experience leading projects or teams in a technical capacity.
• Previous exposure to early-stage startups, ideally in B2B SaaS.
• Strong proficiency in modern front-end frameworks (particularly React).
• Experience designing and integrating REST or GraphQL APIs (bonus if you've built SDKs or documentation).
• Solid understanding of SQL and NoSQL databases and backend architecture.
• Familiarity with cloud platforms such as AWS, Azure, or GCP.
• A pragmatic, product-first mindset—someone who values simple solutions and rapid iteration.
• Strong collaboration and communication skills.

Benefits

• Competitive salary
• 25 days holiday + bank holidays
• Share options in a fast-growing business
• Private healthcare (including dental and optical)
• Flexible working (remote or hybrid - dog-friendly office in London available)
• Strong career development and influence in a key hire

Legal / Notes

• UK right to work required - unfortunately, visa sponsorship isn't available.
• The team is passionate about diversity, inclusion, and building an environment where everyone can thrive and do their best work.
• If you're a hands-on engineer excited by the idea of helping build a product from the ground up and want to join a team that values innovation, ownership, and velocity, we would love to hear from you.