Senior Software Engineer - London

Senior Software Engineer - London ABOUT SEQUENCE If you join Sequence, you'll help build the platform that lets companies get paid - we’re already processing $1bn+ in annual invoice volume and growing fast. We're building the AI-powered revenue platform for modern finance teams, replacing fragile spreadsheets and legacy systems with software their teams love using. Cognition, incident.io, MoonPay, and 100+ other high-growth companies trust us to handle their entire revenue cycle across quoting, billing, and revenue recognition. Founded by repeat entrepreneurs, we hit 10x ARR growth last year and just closed a $20M Series A https://www.sequencehq.com/blog/sequence-announces-series-a led by 645 Ventures, alongside a16z and exceptional founders and CFOs from companies like Decagon, Klaviyo and Wise. WHAT'S IT LIKE TO WORK AT SEQUENCE? Small team, big opportunity, real ownership. You'll do work that matters, have direct access to customers, and grow alongside the company. If you want to do the best work of your career at a company that's scaling fast, we'd love to meet you. THE ROLE We're looking for software engineers with strong backend and cloud infrastructure experience to build the systems that power billing for modern B2B companies. You'll own revenue-critical infrastructure - the kind where correctness isn't negotiable and downtime isn't an option. Our usage events platform processes every merchant action that determines how their customers get billed, making it one of the most critical systems we run. You'll work on the evolution of this platform to handle exponential growth while maintaining perfect accuracy. This is a rare opportunity: you're joining early enough to make fundamental architectural decisions, but late enough that real customers depend on what you build. You'll design systems that process high-velocity event streams, make technical decisions that balance cost and performance at scale, and build infrastructure that never compromises on reliability. WHAT YOU'LL DO: - Own revenue-critical event infrastructure. You'll work on systems that process customer usage data on which billing and invoicing depend. Design event streaming pipelines that handle high throughput with low latency. Build robust systems where data accuracy is non-negotiable and uptime is measured in nines. - Design scalable data systems. You'll work with event streaming architectures, building sophisticated ingestion pipelines and query optimization strategies. Our event volumes grow with every new customer, so you'll architect systems that scale efficiently while keeping costs reasonable. - Shape our backend architecture. You'll tackle our most complex technical challenges and set the standards for how we solve them. Our services run on Kotlin with Spring Boot, and you'll have significant influence over architectural patterns and how we approach infrastructure problems. - Build for the next phase of growth. You'll design systems that work beautifully today and scale to 10x the load tomorrow. This means thinking about data storage strategies, horizontal scalability, and how your architectural decisions affect performance as volume increases. - Drive impact on a small team. We've built an engineering culture around collaboration, learning, and shipping. You'll have significant influence on what we build, how we build it, and how we work together. THIS IS A GREAT FIT IF YOU... - ✅ Love building systems that scale. You've worked on backends that handle significant load and understand the tradeoffs in designing for throughput, latency, and cost. You know when to optimize and when good enough is actually good enough. - ✅ Have strong experience in event-driven architectures. You've built pub/sub systems, worked with event streaming platforms, and understand the nuances of event delivery semantics, backpressure, and ordering guarantees. - ✅ Think deeply about data systems. You've worked with analytical databases or OLAP systems. Y ... (truncated, view full listing at source)