Senior Software Engineer

London · Hybrid, 3 days a week in the office · Senior £95 - 125k / Lead £125 - 155k + share options We're Stream, the world's first social impact unicorn. More than four million workers use Stream to get a fairer deal with their money. We reach them through 2,000+ employers, including Greene King, Bupa, Burger King, Asda and the NHS, and it all runs through one simple app where people can earn, learn, save, spend and borrow on terms that actually suit them. We're VC-backed, growing fast and making waves with our financial wellbeing products. We operate under a social charter that holds us accountable: every product we create has to measurably improve financial wellbeing. Moving money for millions of people, at pace, leaves no room for getting it wrong. That's what makes the work worth doing. Why this role is different: The agent types; you decide. Every engineer gets company-paid Claude Code, and agents write most of our code. There are usage caps, but they're guardrails rather than limits: hit one and we'll raise it. Typing time has gone down and decision density has gone up. So we hire for judgement: what to build, what to cut, when to step in and when to let the agent run. You own every line that ships.A small team with a big footprint. Around 45 people across product and engineering, in small cross-functional pods, serving millions of people in the UK and US. Your work is visible, and it matters.Engineers pitch the work. Anyone, at any level, can write an RFC, and good ones get built: our engineers wrote more than 30 in August and September alone. In January one of our engineers proposed connecting our Figma design system to Claude Code, so agents build screens from our real components instead of guessing. Two months later it was live in the UK app. What you'll work on: The team you join depends on your experience and where you'll have the most impact. Most of the work is making proven products better for millions of people. Some of it is greenfield. FlexPay: our earned wage access product in the UK and US. Simple, trusted experiences built on payroll integrations and money-moving services at scale.Credit: responsible workplace loans, covering eligibility, decisioning, servicing and repayment, with real regulatory rigour. Live in the UK and expanding in the US.Wealth: our emerging workplace savings product. It's early-stage, with plenty of room to shape it.Benefits & Discounts: helping employees' money go further through benefits and everyday savings, powered by partner integrations.Integrations: working with our Delivery team to connect new employers' payroll and workforce systems so they can launch on Stream.Internal tools: the tools that help Stream teams give clients and their employees a better experience. Two of the hard problems you'd be working on: Payroll data from dozens of providers. Every employer runs pay differently: Workday, Zellis, ADP, Sage, Fourth, even servers in a customer's own building. We turn all of it into an accurate, up-to-date figure for what each person has earned, because that figure is what they can draw.Money across rails. Faster Payments, SEPA and US payment rails, direct debits and card repayments, across several banking providers. When a bank's API times out, the payment may still have gone through; retry blindly and someone gets paid twice. Every penny has to reconcile. How we work: Value, Speed, Simplicity, in that order. Everything we build is tied to a real user need. We prefer short feedback loops to polished first attempts. We build the smallest thing that works.Stack: Python (Flask), Postgres, Celery and AWS (ECS, Lambda, SQS) on the backend; React and TypeScript across web and mobile; GitHub Actions for CI/CD. Experience with our stack helps, but isn't required.Cross-functional by default. You'll work day to day with product, design, data, delivery and commercial colleagues, not from a ticket queue. What success looks like: By month 1: you've shipped your first change to production, met your team and the people you'll work with across the business, and understand how money moves through our platform.By month 3: you're owning problems from discovery to production, whether that's an employee-facing feature, a new employer integration or an internal tool. You've pitched at least one idea of your own.By month 6: you own a significant area. As a Senior, you're raising the quality bar in your pod. As a Lead, you're also setting technical direction across a wider area and helping other engineers do their best work. What we're looking for: A track record of building and running customer-facing software in production, whether web, mobile or backend services and integrations.Sound judgement: you can turn an ambiguous problem into the simplest thing that works, and explain what you chose not to build.Experience with, or real curiosity about, working with AI coding agents: directing them, checking their output and knowing when to take over.Care for reliability, security and data protection. This is people's money.For Lead: you've set technical direction across more than one team or system, and made the engineers around you better. You don't need a background in financial services. If you're close but don't tick every box, we'd still love to hear from you. Benefits: 25 Days Annual Leave in addition to public holidays (up to 5 days rollover), plus flexible time off for ad-hoc childcare, family, or caring needs24 weeks' paid Maternity Leave and 4 weeks' paid Paternity Leave for employees with over 12 months' serviceSpecial Leave for IVF and other fertility treatmentsSabbatical schemePaid volunteering leave - give back on usPrivate Healthcare including comprehensive mental and physical health supportPension salary sacrifice - plus bonus exchange to pension, saving on Tax and NI with added compound growthElectric vehicle salary sacrifice schemeSeason Ticket LoanAccess to ThanksBen - THE benefits marketplace. Choose what you want, when you want: Workplace Nurseries, Cycle to Work, Home and Tech Scheme, and moreAnd the best benefit of all - access to Stream for your own financial wellbeing How we hire It takes about three weeks from application to offer. Initial call: a short chat about you, the role and what you're looking for.Technical discovery: a conversation about your experience, your technical knowledge and the things you build for fun.Live build: a 60-minute screen-shared session where you build with your own AI tools and your preferred stack. There's no take-home and no prep; we share the brief on the call.Values chat: a final conversation about how we work and whether Stream is right for you. Our commitment At Stream we celebrate and support our differences. We know employing a team rich in diverse thoughts, experiences, and opinions allows our employees, our product and our community to flourish. Stream is an equal opportunity workplace. We are dedicated to equal employment opportunities regardless of race, colour, ancestry, religion, sex, national origin, sexual orientation, age, citizenship, marital status, disability, gender identity/expression, or veteran status.