Senior Software Engineer

Senior Full Stack Engineer | Hybrid in Central London | Up to £100k DOE

We're partnering with an ambitious SaaS business that is entering a pivotal stage of growth and transformation.

Having successfully built a profitable software platform serving thousands of customers globally, the business is now bringing technology ownership fully in-house and building an internal engineering function.

This is an opportunity to join at an exciting stage of the company's journey and play a key role in shaping the future of the technology organisation. You'll work closely with senior leadership, helping establish engineering standards, technical direction, development processes and best practices as the team continues to grow.

About the Business

Established SaaS platform with strong recurring revenue

Serving thousands of customers globally

Significant growth plans over the next five years

Product-led organisation operating in the health, fitness and coaching technology sector

Strong leadership team with experience scaling successful consumer and technology businesses

Long-term focus on AI adoption, automation and data-driven product development

What You'll Be Doing

As a senior member of the engineering team, you'll have broad ownership across product development, platform improvements and technical decision-making.

Taking ownership of core product development across backend, frontend and infrastructure

Helping establish engineering standards, processes and best practices

Driving improvements in testing, deployment and documentation

Contributing to architecture and platform modernisation initiatives

Supporting cloud migration and infrastructure evolution

Working closely with product and design teams to deliver new features

Mentoring engineers as the team grows

Helping shape the company's AI-assisted engineering strategy

Technology Stack

Ruby on Rails, PostgreSQL, Redis, Sidekiq, Vue.js, AWS, Docker, GitLab, Cloudflare

What We're Looking For

Essential Experience

Strong commercial experience building and maintaining production Ruby on Rails applications

Full-stack development capability across backend and frontend technologies

Experience working with PostgreSQL in high-volume production environments

Strong understanding of cloud infrastructure and AWS services

Experience with Docker and modern deployment pipelines

Solid knowledge of REST APIs, authentication and system integration

Strong automated testing mindset, ideally with RSpec and TDD practices

Experience owning features and services end-to-end

Ability to operate autonomously in a fast-moving environment

Highly Desirable

Sidekiq and background job processing expertise

Stripe or payment platform integrations

Event-driven architectures

WebSockets / real-time applications

AI-assisted development workflows and tooling

Experience scaling SaaS platforms

Startup or scale-up experience

The Ideal Person

You'll likely thrive here if you are:

Product-minded and commercially aware

Comfortable working with ambiguity

Naturally curious and self-directed

Strong communicator who can explain technical concepts to non-technical stakeholders

Excited by ownership and accountability

Interested in helping shape engineering culture and technical standards

Passionate about modern software engineering practices

What's on Offer?

Salary up to £100,000

Potential bonus scheme

Unlimited annual leave

Hybrid working (3 days per week in office)

Opportunity to influence technical direction and engineering standards

Work on complex platform, infrastructure and migration projects

Join a growing SaaS business with ambitious expansion plans

If you're an experienced full-stack engineer who enjoys taking ownership, solving complex technical challenges and working in a collaborative, fast-moving environment, we'd love to hear from you.