
Stacks · London
About Stacks Stacks is building an AI-native platform that reinvents how modern finance teams run the monthly close. The opportunity is massive: every growing ...
About Stacks
Stacks is building an AI-native platform that reinvents how modern finance teams run the monthly close. The opportunity is
massive: every growing company depends on accurate, timely financial data, yet most are still operating with tools and workflows
built for a different era.
In just two years, we’ve grown from a team of 2 to 30+ and are on a rapid trajectory towards $10m ARR. We’ve raised a $23m Series
A led by Lightspeed Venture Partners, and we were recently recognised as one of Harmonic’s Hottest Startups of 2026.
We’re already trusted by leading European scale-ups including Pleo, Freetrade, and Motorway.
Our team is a blend of finance, product, and technical experts from top-tier companies like Uber, Plaid, Miro, Meta, Mollie, and
Bunq, united by the drive to create a game-changing solution.
We’re a team that is deeply customer-obsessed, plays to win, and isn’t afraid to take big, bold bets. We move fast, hold a high
bar, and are committed to growing together as we scale.
🔎 About the Role
Stacks is looking for a Staff Product Engineer to set the technical standard for how we build. This is not a management role. It
is an individual contributor role with outsized influence, where your decisions shape architecture, unblock teams, and define what
great looks like across the entire engineering organization. You will work at the intersection of complex technical problems and
real customer outcomes. You will be the person others come to when the problem is hard, when the trade-off is unclear, or when the
stakes are high. You will define the approach, not just execute it
🧱 What You'll Do
production reliability.
others build on for years.
ambiguous problems into elegant, scalable solutions.
and use what you learn to sharpen what we build.
engineering looks like in practice.
raising the bar in code reviews, mentoring engineers, and evolving AI-native engineering workflows.
Our product and technology are always evolving, so being a fast learner matters more than knowing our stack on day one. Here is
Frontend: React, Next.js
Backend: Node.js, Express, TypeScript, Python, Protobuf
Data and Infrastructure: PostgreSQL, Redis, Google Cloud Platform, Terraform
🧩 What You Need
Ownership and DRI mindset: You own problems end to end, create clarity when none exists, and take responsibility for outcomes
without waiting to be told what to do next.
Full stack depth with a backend focus: Strong TypeScript and Node.js fundamentals, comfortable across the stack, solid on API
design, async processing, failure handling, and data modelling.
Judgment under ambiguity: You make high-quality trade-offs between speed, correctness, and long-term system health. You choose
simple and scalable where others over-engineer.
Product and customer mindset: You think in customer problems, not tickets. You have talked to users and used what you learned to
change what you built.
Learning speed: You close gaps independently and with urgency. You do not need a long ramp-up or structure to orient yourself.
Execution and reliability: You have shipped things that mattered and felt personally responsible when they did not work. You
design for failure from the start.
Influence and leverage: You make the engineers around you faster and better through how you write code, share context, and raise
issues.
🚀 What’s in It for You
high-agency team.
the outcome.
companies run their financial close.
gym, classes, and an environment built for focused, in-person building
anniversary party in Amsterdam, with board games, a tarot card reader and live music 🎶
🤝 The Hiring Process
We move fast. Most candidates complete the full process within two weeks
looks like here
trade-offs that matter
Attio is the CRM built for the AI era. Designed for the most ambitious go-to-market teams, it gives companies the power to understand every customer, automate at scale, and build their go-to-market motion exactly as they need. We've raised $116M from some of the world's best investors: GV (Google Ventures), Redpoint, Balderton, Point Nine, and 01A. We hire builders who thrive on complex technical challenges, hold themselves to a high bar, and genuinely care about delighting the people who use what they build. The team here brings sharp judgement, real craft, and the drive to do exceptional work. We're obsessed about the details and energized by the frontier. If you want to do the best work of your career, this is the right place. ABOUT THE ROLE Our Engineering team tackles the toughest challenges, so our users never have to. Real-time infrastructure, AI-native architecture, and a frontend that feels effortless - all powered by a team that moves fast, thinks rigorously, and holds an exceptionally high bar for quality. We’re looking for Staff Product Engineers that can solve our hardest technical problems, both individually and through technical leadership. You’ll design and build software that creates delightful, groundbreaking user experiences. You’ll play a key role in growing the talent in our engineering organization through mentoring, coaching and hiring, and you’ll resolve our most tricky product issues through an understanding of what’s important to our users and business. WHAT YOU'LL DO * Provide technical leadership for a critical part of Attio’s engineering organization. You’ll work across teams to design significant parts of our infrastructure, aligning with Attio’s overall technical strategy. You’ll hold a high bar for the output of the teams you work with, ensuring that Attio executes both quickly and with quality. * Raise the bar on how we build and operate software. You’ll be part of a technical leadership group that sets standards for how we build and operate software at Attio, ensuring that we strive to build robust and maintainable systems that are reliable, scalable and secure. * Grow our engineering talent. You’ll mentor and coach the engineers you work with, and help ensure we hire the best talent for Attio. You’ll share your knowledge and growth mindset with the team, and be open to new approaches and experiments as software engineering evolves in the age of AI. * Deliver for the business. You’ll always look to optimize for Attio’s business, ensuring that we make the right trade-offs between delivery and perfection. You’ll strive to understand our customers and users so you can deliver the experiences which are uniquely valuable to them. WHAT YOU'LL BRING * First-class technical skills. First and foremost, you’ll be an excellent technical executor, with an ability to think in systems, not just crank out code. You’ll understand the world of distributed, cloud-native systems, and intuitively create the right interfaces to allow teams to innovate in parallel. * Proven technical leadership credentials. You’ll have a track record of not just personal execution, but of delivering projects through others. You’ll be able to break down large, complex problems into smaller, independent goals that others can own. You’ll understand how technical architecture impacts ability to deliver, and to maintain systems for the long term, and be sensitive to the need to pick the right compromise. * A growth mindset. Software engineering is changing rapidly in the age of AI, and you’ll understand the need to be open-minded and to experiment. You’ll be keen to teach, and to learn from the experience of others. You’ll relish the challenge of working in an area that’s new to you, and enjoy the discomfort that leads to personal growth. * A passion for growing the skills of others. As you deliver projects through your technical leadership, you’ll be keen to grow the next generation of technical leaders. You’ll have demonstrated impact through mentoring and coaching, and be able to flex your style depending on the needs of your colleagues. You’ll also be passionate about hiring the right talent for Attio. * A focus on the product and customer. You’ll have strong opinions on what makes a great product, and a keen desire to deliver the things which generate value for Attio’s customers. You’ll be curious to learn about how our product is used in the field, and have an understanding of how to use data to ensure we’re building the right thing. WHAT WE OFFER * Competitive salary : £135K- 170K * Equity in an early-stage tech company on an incredible trajectory * 25 days holiday plus local public holidays * Apple hardware * [In the UK] Private medical insurance through AXA * [In the UK] Pension contribution through Hargreaves Lansdown * Enhanced family leave * Team off-site in fun places! (We've been to Barcelona, Lisbon, Malta, and Split so far)
🐦 About Birdie At Birdie, we’re reimagining care for older adults. We’re building the technology that powers the future of home healthcare, empowering care teams with tools to deliver better, more dignified care, and enabling older people to thrive in their own homes for longer. Our all-in-one solution powers millions of care visits every month, equipping care providers with the tools they need to deliver exceptional, efficient care. We’re not here to tinker at the edges. We’re here to radically transform a broken system. That’s why we’ve built an all-in-one platform that supported over 60 million care visits and enabled care for 116,000 individuals in 2025, and we continue to grow our impact. We’re scaling fast, but staying true to our purpose. That’s why we’re proud to be a B Corp, using business as a force for good. Founded in 2017, Birdie is backed by world-class investors like Index Ventures, Sofina and Omers. In 2025, we ranked #23 in the Sunday Times Top 100 tech list, making us one of the fastest-growing tech companies in the UK. You can check out more about our impact and recognition here. ⚡️ Your Mission We’re evolving Birdie’s platform to be AI-first. We’re building intelligent systems that assist decision-making, automate coordination work, and surface insights directly within real care workflows. This shift will shape the next generation of our product, and we need a designer who can help lead the way. If you’re excited about using AI to fundamentally reshape how care is delivered, this is the role for you. This role sits within the Care Management squad, one of the most complex and consequential parts of our product. Care teams use this area to assess needs, build care plans, coordinate visits, and maintain quality of care across hundreds of providers. You’ll own design for parts of this domain while also contributing to the broader AI-first direction across the platform. Beyond your squad, you’ll raise the design bar across Birdie through critique, mentorship, and systems thinking that brings greater coherence to the whole product. You’ll partner closely with Product and Engineering to frame problems, shape solutions, and drive outcomes, contributing to product direction as much as craft. Six months in, here’s what good looks like: You’ve helped define Birdie’s AI design direction and it’s actively shaping what we build. You’ve shipped meaningful improvements in Care Management. The design practice across the team is visibly stronger because of your influence. 🤩 You’ll Thrive Here If… You’ve been designing digital products for 7+ years and you have a strong track record as a senior IC. You’ve owned complex problem spaces from ambiguous 0→1 work all the way through to polished, scalable delivery. You’ve spent real time in a startup or scale-up, so you know what it feels like when priorities shift fast and you’re often the only designer in the room. When you look at a screen, you also see the workflow it sits inside, the data flowing through it, and the person under pressure who has to use it at 7am. You think in systems, not just screens. You have sharp product judgment and you know when to lean on established patterns, when to challenge them, and how to make principled trade-offs. Your craft bar is high across both UX and UI, with real care for clarity, usability, and visual polish. You’re a genuine partner to Product and Engineering, not someone waiting for a brief. You communicate persuasively enough to align stakeholders and articulate design rationale clearly. And you make the people around you better, whether that’s through mentorship, critique, or simply setting the standard others follow. It’d be a bonus if you’ve worked at a Series C or earlier SaaS startup, or have a background in healthtech, back-office or operational tooling. We’d also value hands-on experience designing AI-enabled or automation-heavy workflows, and familiarity with designing for non-technical users in high-stakes environments. 🧠 Imposter syndrome is real — and we don’t expect you to tick every box. If our mission excites you and you think you could make a difference here, we want to hear from you. 🌈 What You’ll Get From Us We believe people do their best work when they’re supported, trusted and inspired. Here’s how we build a world-class employee experience: 💸 Compensation * Competitive base salary of £110k –£130K, reviewed against benchmarks annually * Generous stock options – because we’re building this together * Bi-annual performance cycles with individual compensation reviews 🧠 Learning & Growth * Annual personal learning budget and access to training, coaching, and mentorship * Time and space for growth – you set your development goals, we back them 🏡 Flexible Working * Hybrid working – 2 days per week in our incredible London HQ in Waterloo if you are in London or 2 days per month if you are outside of London (with its own roof terrace!) * Budget to set up your home workspace * Regular in-person meetups, socials, and offsites 🏖️ Time Off * 33 days holiday (25 days + public holidays) * Extra day off on your birthday (use it whenever you like!) * Company shutdown between Christmas and New Year * 2 volunteering days each year to give back to causes that matter 👶 Family-first Policies * Industry-leading paid primary and secondary caregiver leave * 5 paid days for fertility treatments for those who need it * Private health insurance with AXA * Wellbeing perks via Happl (gym discounts, mental health support, and more) 🚲 Other Perks * Cycle to work scheme * 4% employer pension contribution when you contribute 5% * A deeply human, radically transparent culture ❓ Why Birdie? Because you want to do meaningful work that improves lives – and grow at speed while doing it. We’re building more than a product – we’re building a movement. A movement to show that tech, when built with empathy and integrity, can change lives. We’re a team of entrepreneurs, dreamers, and doers. Join us to shape the future of care, work alongside ambitious, kind people, and help reimagine how society cares for its older adults. We dream big, act fast, and work collaboratively with one goal in mind: to create a world where we all age with confidence. ⚖️ Equal Opportunities Statement We’re committed to building a diverse team and inclusive culture. That means creating a hiring process that gives everyone a fair chance regardless of background, identity, or lived experience. Need adjustments or support during the application process? Let us know. We’re here to help. ✨ Ready to build the future of care? Apply now. Be part of something that matters.
WHY FACULTY? We established Faculty in 2014 because we thought that AI would be the most important technology of our time. Since then, we’ve worked with over 350 global customers to transform their performance through human-centric AI. You can read about our real-world impact here. We don’t chase hype cycles. We innovate, build and deploy responsible AI which moves the needle - and we know a thing or two about doing it well. We bring an unparalleled depth of technical, product and delivery expertise to our clients who span government, finance, retail, energy, life sciences and defence. Our business, and reputation, is growing fast and we’re always on the lookout for individuals who share our intellectual curiosity and desire to build a positive legacy through technology. AI is an epoch-defining technology, join a company where you’ll be empowered to envision its most powerful applications, and to make them happen. ABOUT FRONTIER Frontier is building the system for running high-stakes decisions at the organisations that run critical parts of the economy — hospitals, life sciences companies, manufacturers. Frontier is an Intelligent Decision System that combines enterprise data, AI, simulation, optimisation, and human judgement to support the full decision loop — from understanding a situation, to evaluating options, to taking action and learning from the outcome. We don’t believe in AI that thinks for people. We believe in AI that helps people think - humans and agents working together inside a decision system. Done well, people operate with more speed, more evidence, and more confidence than they ever could alone. We're starting with clinical development decisions in life sciences — one of the highest-stakes, highest-complexity decision environments there is — and architecting to scale from there. Frontier is a product of Faculty, an AI company that's been working with some of the world's most consequential organisations since 2014.. ABOUT DESIGN AT FRONTIER We’re a small team, growing deliberately - we’d rather have five designers who trust each other than fifteen who don't. We're tightly integrated with engineering. We prototype in code. We co-own the design system with developers. We're actively exploring what agentic-augmented design work looks like in practice, not in think pieces — and we're honest when we don't have the answer yet. We’re active in shaping the product culture at Frontier; putting people first, raising the quality bar and ensuring a coherent experience. You’ll be part of shaping that culture. ABOUT THE ROLE You'll be one of the most senior designers on Frontier, shaping a product that's still early enough that the decisions you make will define how it works for years. Day to day, you'll be designing the surfaces where people and agents collaborate on real clinical decisions — how evidence gets surfaced, how recommendations get explained, how humans push back, how teams learn. This is hard, unsolved design work. The existing patterns for AI interfaces mostly come from consumer chat products; they don't transfer cleanly to environments where the cost of a bad decision is measured in years of research or patient outcomes. You'll be expected to work end-to-end: from framing the problem with product and engineering, through prototyping in code and design canvases, through shipping. You'll help set the craft bar for the team, mentor the designers around you, and push back when something isn't good enough yet. WHAT YOU'LL WORK ON * Designing the core interaction patterns for how humans and agents collaborate inside a decision loop. * Making dense, analytical information legible for expert users who need to trust it, challenge it, and act on it. * Shaping the shared design language and system that lets a small team move quickly without the product fragmenting. * Partnering with engineering from day one of any problem, not from handoff. * Raising the bar for craft — through your own work, through critique, and through the standards you hold the team to. WE THINK YOU'LL DO WELL HERE IF * You've shipped complex software for expert users, in a domain where getting it wrong has real consequences. * You design end-to-end and care about the pixels as much as the strategy. * You've done serious work on AI or other non-deterministic systems and have opinions about what works and what doesn't. * You're comfortable prototyping in code, or motivated to get there. * You're direct, kind, and can hold a clear point of view without needing to be the loudest in the room. * You want the people who use your product to have better working lives because of it. YOU MIGHT NOT ENJOY THIS ROLE IF * You want to work on a mature product with established patterns. Frontier is early, and the ambiguity is real. * You prefer to work handoff-style, away from engineers. * You're looking for a role where design sets direction in isolation from product and engineering. We work as one team. INTERVIEW PROCESS 1. Intro call with our talent team (30 min) 2. Conversation with Duncan, VP of Design (60 min) 3. Portfolio and case study deep-dive (90 min) 4. Final conversation with a cross-functional leader (60 min) OUR RECRUITMENT ETHOS We aim to grow the best team - not the most similar one. We know that diversity of individuals fosters diversity of thought, and that strengthens our principle of seeking truth. And we know from experience that diverse teams deliver better work, relevant to the world in which we live. We’re united by a deep intellectual curiosity and desire to use our abilities for measurable positive impact. We strongly encourage applications from people of all backgrounds, ethnicities, genders, religions and sexual orientations. Some of our standout benefits: * Unlimited Annual Leave Policy * Private healthcare and dental * Enhanced parental leave * Family-Friendly Flexibility & Flexible working * Sanctus Coaching * Hybrid Working If you don’t feel you meet all the requirements, but are excited by the role and know you bring some key strengths, please don't hesitate in applying as you might be right for this role, or other roles. We are open to conversations about part-time hours.