Staff Product Engineer

Stacks

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 * Own the most technically complex and highest-impact problems in the product, end to end, from architectural vision through to production reliability. * Define technical direction across the engineering team: set patterns, establish standards, and make foundational decisions that others build on for years. * Leads cross-functional technical discussions, partnering closely with product, design, and the founding team to translate ambiguous problems into elegant, scalable solutions. * Join customer calls and engage directly with finance leads and CFOs. You will bring technical depth to commercial conversations and use what you learn to sharpen what we build. * Identify and resolve systemic risks before they become production incidents. You design for failure, not around it. * Raise the bar for the whole team: through code reviews, technical mentorship, and by modelling what rigorous, thoughtful engineering looks like in practice. * Lead by example as an active contributor: not only setting technical direction, but consistently writing production code, 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 what we are currently building with: 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 * Foundational role: Help shape a category-defining company from an early stage, working directly with founders and a small, high-agency team. * Cutting-Edge Technology: Work at the forefront of the AI revolution in a product where AI is core, not bolted on * Meaningful ownership: Competitive equity in a company scaling rapidly towards $10m ARR, where your impact will directly shape the outcome. * Cutting-edge product and tech: Work at the intersection of AI and finance, building systems that fundamentally change how companies run their financial close. * High-calibre team: Collaborate with people from companies like Uber, Plaid, Miro, and Mollie. * Exceptional workspace: Our London HQ is based in Fora — a modern, design-led space in the heart of the city with access to a gym, classes, and an environment built for focused, in-person building * Strong team culture: We run regular socials and off-sites that bring the team together properly, we recently have our 2-year 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 * Step 1: 30 min intro chat with our TA team to learn more about Stacks and get genuinely excited about what we are building * Step 2: 45 min product and tech chat to explore how engineering and product collaborate at Stacks and what ownership really looks like here * Step 3: 90 min system design, your chance to show how you translate product requirements into technical architecture and make trade-offs that matter * Step 4: 60 min coding session, a focused moment for you to tackle a real engineering problem the way you would on the job * Step 5: 45 min onsite conversation with our Founder about Stacks culture, values, and the journey ahead * Step 6: Offer. If we have gotten this far, we are excited about you and we will make that clear

Tessl

Tessl is a fast-growing Series A startup based in London, founded by Guy Podjarny. We’ve raised over $100M from world-class investors including Index Ventures, Accel, GV, and Boldstart, and in 2025 we were ranked #2 in Sifted EU’s B2B SaaS Rising 100 and #20 in Sifted's AI 100. At Tessl, we are building the context layer for AI coding agents, and a platform for AI-native software development. As an early member of the team, you’ll help shape how we build, scale and support a company operating at the edge of AI and software development. ABOUT THE ROLE We're looking for a Member of Product Staff — a senior, hands-on product manager who can own ambiguous, high-stakes problems end to end and help define how product is practised as the team grows. This is a generalist role. The patterns for how developers work with AI agents are still forming, and you'll have a direct hand in shaping them across the product — from the CLI and core platform to the new bets we'll place as we expand. Much of the work is 0-to-1: you'll shape product direction amid genuine ambiguity, translate fast-moving model and research breakthroughs into experiences developers trust, and decide what's worth building when there's no settled playbook. We also expect this person to be building a genuinely AI-native product practice: using the best available tools to think more clearly, move faster, and raise the quality of the work. We're not looking for someone who uses AI occasionally — we want someone actively developing how they work with it, and setting the standard for the team. WHAT YOU'LL WORK ON * Own product areas end to end. Take problems from early concept through discovery, definition, launch, and iteration — setting priorities for a cross-functional team and making the calls on what matters most. * Develop deep product sense for developer workflows. Spend real time with developers and engineering teams to understand how they think, where they struggle, and where AI creates the most leverage. Turn those observations into specific, well-reasoned product decisions. * Translate frontier capability into product. Partner closely with engineering and research to turn new model capabilities and agentic breakthroughs into reliable, high-value developer experiences. * Shape strategy, not just execute it. Bring a clear point of view to roadmap and direction. You'll be in the room for strategy conversations and expected to help shape outcomes, not just respond to decisions already made. * Lead through influence. Act as the connective tissue between engineering, design, research, GTM and leadership — and as a credible voice with customers. Keep a globally-minded, fast-moving team rowing in the same direction. * Maintain a high quality bar at speed. Ship quickly without losing rigour, and hold the line on quality and developer trust even when the product is changing fast. * Build an AI-native product process. Define which tools and workflows raise quality and pace, share what you learn, and help set how product gets done at Tessl. WHAT WE'RE LOOKING FOR * Experience: Roughly 6+ years in product management (or equivalent), with a track record of shipping real, technically demanding products end to end. Comfortable operating at a senior IC level with significant autonomy. * Product sense & judgment: Strong instincts for what to build and why, backed by good business judgment and the ability to reason clearly under ambiguity and incomplete information. * Technical fluency: A track record of building for technically sophisticated users — developers, engineers, or data professionals. You don't need to be an engineer, but you should be genuinely curious about how the systems you build for actually work, and able to partner with research and engineering at a technical level. * 0-to-1 instinct: Comfortable shaping direction where there's no settled product, market, or process. You're drawn to ambiguity rather than unsettled by it. * Collaboration & communication: Excellent communicator who can align and influence engineers, designers, researchers and leaders who think differently to you. Confident enough to hold a point of view, flexible enough to run with the best idea wherever it comes from. * Domain experience (a plus): Developer tools, AI/ML applications, or productivity infrastructure. Exposure to CLI tooling, agentic workflows, or evaluation systems is a genuine advantage. We don't have all the answers yet. This is a role where you'll help define new patterns, work at the edge of what's known, and shape how product is practised at a company still figuring things out in the best possible way. If that excites you, and you feel you'd be a strong fit even if you don't meet every criterion listed, we'd encourage you to apply. SALARY AND BENEFITS Office: Our brand new 10,000 sq. ft office is in the AI hub of Kings Cross, London. We have generous catering and regular social events such as team lunches, drinks and more. We require all staff to be in our London HQ at least 3 days a week on our anchor days of Monday, Tuesday and Thursday. Salary: We offer a competitive salary commensurate with experience and skills and employee share options, benchmarked against industry standards. Benefits: 25 days holiday, health insurance, including dental and vision, which extends to partners and dependents, as well as a company-matched pension. We also provide a commuting stipend for those who live outside London, and a cycle to work scheme. APPLICATION PROCESS 1. Screening call 2. Case study presentation (with the hiring panel) 3. Final round — cross-functional collaboration, leadership, and a hands-on PM workshop 4. Leadership Chat We care deeply about the warm, inclusive environment we’re building at Tessl and we value diversity – we welcome applications from those typically underrepresented in tech. If you like the sound of this role but are not totally sure whether you’re the right person, do apply anyway! LEARN HOW WE THINK AND WORK * On Tessl, The AI Native Development Startup * Announcing skills on Tessl: the package manager for agent skills * Podcast Episode: The End of Fragmented Agent Context, Guy Podjarny Tessl CEO

Tessl

Tessl is a fast-growing Series A startup based in London, founded by Guy Podjarny. We’ve raised over $100M from world-class investors including Index Ventures, Accel, GV, and Boldstart, and in 2025 we were ranked #2 in Sifted EU’s B2B SaaS Rising 100 and #20 in Sifted's AI 100. At Tessl, we are building the context layer for AI coding agents, and a platform for AI-native software development. As an early member of the team, you’ll help shape how we build, scale and support a company operating at the edge of AI and software development. About the role Tessl is building the foundational infrastructure for how developers work with AI agents: the systems, standards, and tooling that make agent-assisted software development reliable, repeatable, and trustworthy at scale. We are a small team working on a genuinely new class of problem, and design is central to how we solve it. We are looking for a Member of Design Staff who brings real craft and genuine curiosity. You will work closely with product managers, engineers, and researchers to shape how developers interact with technically complex systems and workflows. This is not execution work within a settled product. The patterns are still forming, and the person we hire will have a direct hand in shaping them. We also expect this person to be building a genuinely AI-native design practice: using the best available tools to move faster, think more clearly, and raise the quality of our work. We are not looking for someone who uses AI occasionally. We want someone who is actively developing how they work with it. What you will work on * Design clear, usable interfaces across core product surfaces and developer workflows, balancing simplicity with the depth and configurability that expert users need. * Translate nuanced system concepts into experiences that feel considered rather than overwhelming, grounding design decisions in real user behaviour and research. * Run user research with developers and engineers, turning genuine observations into well-reasoned, specific design decisions. * Collaborate daily with product managers and engineers throughout the full cycle of work: contributing early, iterating often, and treating designs as living documents rather than fixed deliverables. You are comfortable taking the lead on design direction while staying responsive to how the product evolves around you. * Contribute to a growing design system, bringing visual rigour and coherence to shared foundations that will hold up as the product and team scale. * Develop an AI-native design process: use current tools across research, prototyping, and visual production, share what you learn with the team, and raise the bar for how design work gets done. What we are looking for * Experience: 3 to 5 years of experience in product design, or equivalent, with a portfolio showing end-to-end ownership of real, shipped work. Strong visual design sensibility evident throughout. * Technical fluency: A track record of designing for technically sophisticated users. You do not need to be an engineer, but you should be genuinely curious about how the systems you design for actually work. * Tools and working practice: Strong proficiency in Figma, including component architecture and design system contribution. Comfort using AI tools as a serious part of your workflow, from research through to production. Familiarity with tools such as Dovetail is a plus. * Collaboration: You work well in a fast-moving environment where priorities can shift and process is still forming. You are confident enough to take the lead on design direction and bring a clear point of view, but equally comfortable running with an idea that comes from elsewhere in the team. You know the difference between holding your ground on something that matters and being flexible when the situation calls for it. Daily collaboration with engineers and product managers is the norm here, not the exception. * Domain experience: Prior experience in developer tools, productivity software, or AI/ML applications. You understand what it means to design for expert users. We do not have all the answers yet. This is a role where you will help define new patterns, work at the edge of what is known, and shape how design is practised at a company that is still figuring things out in the best possible way. If that kind of challenge excites you, and you feel you would be a strong fit even if you do not meet every criterion listed, we would encourage you to apply. APPLICATION PROCESS Here’s an outline of what you can expect during our interview process: 1. Introductory call 2. Portfolio Review with Designer(s) 3. Case study / White boarding 4. Meet with Head of Product 5. Leadership discussion We care deeply about the warm, inclusive environment we’re building at Tessl and we value diversity – we welcome applications from those typically underrepresented in tech. If you like the sound of this role but are not totally sure whether you’re the right person, do apply anyway! LEARN HOW WE THINK AND WORK * On Tessl, The AI Native Development Startup * Announcing skills on Tessl: the package manager for agent skills * Podcast Episode: The End of Fragmented Agent Context, Guy Podjarny Tessl CEO