Senior Software Engineer - London

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 led by 645 Ventures, alongside a16z and exceptional founders and CFOs from companies like Decagon, Klaviyo and Wise.

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.

We care deeply about the quality of the product we're building. We're looking for ambitious software engineers with strong backend and cloud infrastructure experience to build the systems that power billing for modern B2B companies.

Here’s 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.

• 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.

We're a lean team growing to 20+ engineers. You'll have real influence on what we build and how we build it. Early enough to shape fundamental architecture. Late enough that customers depend on what you ship.

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.

This is business-critical infrastructure: a dropped event means someone isn’t charged correctly. An outage at month-end means finance teams can't collect revenue from their customers.

See more of what we’ve shipped in our public changelog.

You're a builder who wants to solve problems end-to-end:

• You've shipped production backend systems and care about the difference between "it works" and "it's reliable"

• 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.

• You 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.

• You think deeply about data systems. You've worked with analytical databases or OLAP systems. You can reason about columnar storage, indexing strategies, and query optimization without needing a whiteboard

• You own your infrastructure. You've provisioned cloud resources, written infrastructure-as-code, and made architectural decisions that balance competing constraints. You understand how to model and optimize costs as systems scale.

• You care about customers - you want to understand why you're building something, not just what

• You’re comfortable with ambiguity. You thrive in early ideation stages, share work-in-progress to gather feedback, and adapt easily based on input

• You communicate clearly. Thoughtful communication is a superpower that sharpens how we collaborate and build

This might not be right if

We're a small team moving fast on hard problems. That might not be a fit if you:

• Enjoy larger organisation structures and staying only within your area of expertise. Taking ownership here means doing whatever the problem needs

• Want a traditional engineering team set up, with a predictable roadmap and clearly scoped out tickets provided for you

• Prefer a slower pace. Customers are depending on what we ship

• Aren't comfortable with production responsibility. We're revenue-critical infrastructure - on-call matters here

We hire for ability, not a specific tech stack. Most of the team learned our stack here:

• Backend: Kotlin (modular monolith using Http4k, Spring Boot, Exposed, Result4k)

• Storage: Postgres, BigQuery

• Async messaging: Google Cloud Pub/Sub

• Infrastructure: Google Cloud, Terraform

• Frontend: TypeScript, React

• Monitoring: Google Cloud Monitoring, Sentry

• Tools: GitHub, Slack, Notion, Linear

Read our engineering principles

We’re based in London and New York and love spending as much time with our colleagues as possible. We spend three days together in the office, with team lunch on Wednesdays.

We get together twice a year for company offsites.

• Salary: £115,000 - £130,000

• Equity: Meaningful share options

• 25 days holiday + bank holidays

• Modern, flexible pension via Penfold with salary sacrifice available

• Visa sponsorship available

We move fast - typically 2 weeks start to finish. We've written a detailed blog post about the process with tips for how to prepare.