Senior Software Engineer in London

Retire the ERP. Light exists to replace factory-era ERPs with software that feels alive. Our Smart Financial Platform gives modern, global companies superpowers—automated accounting, real-time reporting, and financial flows that move at the speed of the business. We build with our customers, ship fast, and obsess over craft. In a short time, Light has gone from idea to the operating core for leading companies like Lovable, Legora, and Keyshot. People don’t just use Light—they enjoy it.

We’re an early team defining a new software category. Think engineers who love debits and credits, designers who care about reconciliation states, and operators who treat finance as a product. If you’re excited to modernize how the world runs money—one workflow at a time—you’re in the right place. Backed by world-class investors and advised by industry titans, we’re building category-defining products with the freedom to ship ambitiously and own outcomes. Come help us make Light the global default for next-gen finance.

This Senior Software Engineer role is for builders who can take a customer problem from idea to production, wherever in the stack it lives. At Light, AI writes code and the bottleneck has shifted from writing to thinking, so we want engineers who work end-to-end and ship things that matter. We are primarily hiring at mid-level for this role. Junior candidates who are exceptional and genuinely AI-native are welcome. Senior candidates will be considered by exception; we have strong technical leadership and the bar is high.

Your qualifications:

• 3-7 years of experience ideally, plus...
• You build things. Not prototypes, not demos. Working software in production, doing something real for real users. This is the non-negotiable.
• You're genuinely AI-native. You've changed the way you work because of AI tooling, not just added it to your workflow. You have an instinct for where it helps, where it misleads, and how to use it without losing ownership of the outcome.
• You've built with LLMs. You have hands-on experience building products or features on top of large language models. Agents are a bonus, but working knowledge of how LLMs behave in production is a must.
• You're comfortable across the stack. You don't need to be a specialist in everything, but you can't have a lane you refuse to leave. Our stack is Kotlin and React. If you're strong in one and curious about the rest, that works. If you need someone else to handle the other side of the feature, it doesn't.
• You care about the product. You think about the person on the other end. You notice when something feels clunky, even if it technically works. You have opinions about what good software feels like and you act on them.
• You ship early and often. Small batches. Learn. Go again. You're not precious about your work. You'd rather put something real in front of a customer than spend another week perfecting it in isolation.

Bonus points:

• Experience in fintech or systems where data integrity is non-negotiable
• Familiarity with accounting concepts: debits, credits, reconciliation
• Background in high-growth startups where everything was still being figured out

Our Tech Stack:

We build on AWS, with a Kotlin backend, a React frontend, and infrastructure managed in Terraform. It's a real production system that global finance teams depend on every day. You don't need to have used every piece of it. You do need to be comfortable in this kind of environment: real scale, real customers, real stakes.

The good stuff:

• A competitive salary + potential stock options
• 25 days of annual leave + public holidays in the country where you are based.
• Regular socials and company off-sites
• A huge opportunity for career growth as you'll help shape a market-defining product.

The famous last words:

Working at Light means you're embarking on an exciting journey to reshape the future of multinational financial operations. Our cheat-code is that we've built something like this before - and are now doing it again, only better. Our goal is to make global finance effortless and empower companies to make informed decisions. Join the rocket ship while it's taking off.