Java jobs in United Kingdom

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 role sits at the heart of Light’s onboarding and engineering team. You’ll work closely with our clients, partners, banks and fellow engineers to build the money backbone of the Smart Financial Platform. Payments are a core pillar of Light’s mission — powering everything from cross-border transactions to automated accounting — and your work will directly shape how global businesses move money through our system.

You’ll set up and maintain host-to-host integrations (mainly over SFTP and SWIFT-via-SFTP), exchange SSH and PGP keys, run payment and statement tests, and keep our payment pipelines healthy.

It’s not pure software engineering, but you’ll read and write code when needed, debugging payment formats, checking database records, or improving an integration. If you like combining structured ops work with technical problem-solving, this role is for you.

You’ll work in the Onboarding team, partnering with bank tech teams, customer success, and our engineers.

• Set up and maintain secure host-to-host bank connections (SFTP), including SSH/PGP key exchange and endpoint configuration.

• Integrate and test payment systems end-to-end — from ISO 20022 file validation (PAIN and CAMT) to live penny tests with banks and customers.

• Lead technical bank integrations and payment projects, covering scoping, architecture, and delivery across domestic and international payments.

• Investigate and resolve payment or statement issues using observability tools, logs, and database queries.

• Improve reliability and scalability by streamlining processes, automating playbooks, and building maintainable backend infrastructure.

• 2–3 years of experience building backend systems in payments, fintech, or financial services — ideally with H2H, SFTP, or ISO 20022 integrations.

• Strong backend development skills in Kotlin, Java, Go, or Python, and solid understanding of databases (Postgres or similar).

• Hands-on experience with payment file formats (PAIN and CAMT) and familiarity with SEPA, ACH, Wires, Faster Payments, CHAPS, and Bacs.

• Clear communicator who can collaborate effectively with banks, customers, and teammates across time zones.

• Structured, detail-oriented problem solver who takes ownership and continuously looks for process improvements.

• Practical experience using AI or emerging technology tools to improve productivity, insight, or decision-making, with the ability to apply first-principles thinking to new problems.

• Direct experience integrating with card networks, payment gateways, or banking partners.

• Built or scaled payment services in a high-growth startup.

• Familiarity with AWS infrastructure, Docker, or Kubernetes.

• Hosted on AWS

• Postgres DB

• Kotlin Monolith

• Show us who you are through your application and don’t limit yourself to a resume.

• Share examples of payment projects or integrations you’ve built and delivered.

• Bring metrics to back up your impact (e.g. transaction throughput, time-to-market).

• Tell us why you want to help build Light’s payments foundation.

In addition to being part of a great team and working in a really fun and innovative environment, we offer:

💸 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.

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 🚀