Senior Software Engineer (UK) in London

About Sequence

Backed by a16z and Salesforce Ventures, Sequence is reinventing the accounts receivable category, building a flexible toolkit to help B2B finance teams to scale their revenue collection infrastructure. The team behind Sequence has decades of experience building and operating category‐defining marketplace, machine learning, fintech, and enterprise software companies. We are no ordinary start‐up; the maturity of our leadership and technology means we are operating at a lightning fast pace. This is a fantastic opportunity to be a part of the next wave of innovation for the CFO office, doing your best work with talented, ambitious and creative teammates. Sequence is the ultimate billing and revenue stack for B2B companies. We help our customers design and iterate on their pricing and revenue flows, so they can stay completely focused on their mission without worrying about billing. At the end of your career, we want you to look back at your time with Sequence and say it was the best job you ever had.

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 will 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 optimisation strategies.
• Shape our backend architecture. You will tackle our most complex technical challenges and set the standards for how we solve them.
• Build for the next phase of growth. You will design systems that work beautifully today and scale to 10x the load tomorrow.
• Drive impact on a small team. We’ve built an engineering culture around collaboration, learning, and shipping.

This is a great fit if you...

• Love building systems that scale. You’ve worked on backends that handle significant load and understand the trade‐offs in designing for throughput, latency, and cost.
• 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.
• Own your infrastructure. You’ve provisioned cloud resources, written infrastructure‐as‐code, and made architectural decisions that balance competing constraints.
• Write backend code in strongly‐typed languages. Our services run on Kotlin, though you don’t need prior experience.
• Want to work on something new. The biggest technical decisions still lie ahead.
• Thrive in uncertainty. We’re an early‐stage company.
• Care about customers and their problems. You’ll work directly with customer data and build systems that power their revenue.

This might not be the right role if you...

• Prefer staying in your lane. We’re small and fast‐moving.
• Want a predictable roadmap. We don’t have a year‐long backlog of perfectly scoped tickets.
• Prefer a slower pace. We’re solving real problems for customers today.
• Want startup perks with big company stability. We’re early stage— that comes with excitement and opportunity.

What we offer:

• The salary range for this role is £90,000 - £110,000 + share options.
• Early ownership of critical infrastructure at a fast‐growing company.
• Real architectural influence— your decisions will shape how we build for years.
• A collaborative team that values deep technical work and continuous learning.
• We support remote work within +/- 3 hours of GMT and EST, or you can work from our offices in central London or New York—whatever you prefer.

Our hiring process:

• First interview (15 mins): A 15 minute interview with an engineer to learn more about you and your experience.
• Technical Interview (60 mins): A live pair‐programming exercise with one or two of our engineers.
• System Design Interview (60 mins): Focused on how you approach system design problems.
• Final interview (30 mins): A final interview with our CEO, Riya.