Senior Full Stack 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 revenueServing thousands of customers globallySignificant growth plans over the next five yearsProduct-led organisation operating in the health, fitness and coaching technology sectorStrong leadership team with experience scaling successful consumer and technology businessesLong-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 infrastructureHelping establish engineering standards, processes and best practicesDriving improvements in testing, deployment and documentationContributing to architecture and platform modernisation initiativesSupporting cloud migration and infrastructure evolutionWorking closely with product and design teams to deliver new featuresMentoring engineers as the team growsHelping 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 applicationsFull-stack development capability across backend and frontend technologiesExperience working with PostgreSQL in high-volume production environmentsStrong understanding of cloud infrastructure and AWS servicesExperience with Docker and modern deployment pipelinesSolid knowledge of REST APIs, authentication and system integrationStrong automated testing mindset, ideally with RSpec and TDD practicesExperience owning features and services end-to-endAbility to operate autonomously in a fast-moving environment Highly Desirable Sidekiq and background job processing expertiseStripe or payment platform integrationsEvent-driven architecturesWebSockets / real-time applicationsAI-assisted development workflows and toolingExperience scaling SaaS platformsStartup or scale-up experience The Ideal Person You'll likely thrive here if you are: Product-minded and commercially awareComfortable working with ambiguityNaturally curious and self-directedStrong communicator who can explain technical concepts to non-technical stakeholdersExcited by ownership and accountabilityInterested in helping shape engineering culture and technical standardsPassionate about modern software engineering practices What's on Offer? Salary up to £100,000Potential bonus schemeUnlimited annual leaveHybrid working (3 days per week in office)Opportunity to influence technical direction and engineering standardsWork on complex platform, infrastructure and migration projectsJoin 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.