Senior Full Stack Engineer

👶 About Junior Junior is building the AI operating system for investment research. Our software helps private equity firms, consultants and financial institutions complete high-stakes research workflows dramatically faster - from diligence and memo writing to market mapping, research synthesis and strategic analysis. We’re trusted by several of the world’s top private equity firms, Big Four consultancies and leading financial institutions. Bootstrapped and profitable~£20M+ in revenue, after growing 10x last year60+ people across the company20-person engineering team, doubling to 40 this yearCore stack: TypeScript, Next.js and PostgreSQL You’d be joining early enough to shape the product, engineering culture and company, but with enough traction that everything you build lands immediately in front of demanding, paying customers. 💡 The role You’ll own features end to end - across the frontend, backend and data layer - and ship on a weekly cadence, not a quarterly one. You’ll Ship quickly, then ship againDesign and build entirely new ways of working with computersWork on groundbreaking projects involving LLMsSpeak directly with the clients using what you buildUse those conversations to shape product decisionsHelp define Junior’s engineering culture as the team doubles 🔧 Sample projects Build frontier products capable of ingesting new types of research inputsBuild an extremely low-latency, voice-to-voice survey tool that autonomously conducts high volumes of researchBuild a mobile app from scratch in three weeksCreate segmented knowledge graphs using unstructured-to-structured data transformationsBuild an AI-native CRM with deep links into that knowledge graph 🔥 About you You have 5+ years of engineering experience - we care about demonstrated competence, not pedigreeYou’re genuinely strong in TypeScript, Next.js and PostgreSQL, not merely familiar with themYou can build a polished React/Next.js interface or work through a difficult TypeScript problem live and quickly, without relying on CopilotYou have solid foundations in data structures, system design and PostgreSQLYou’re high-agency and product-mindedYou’ve owned projects end to end, argued for what should be built - not only how - and shipped without being handed a detailed specificationYou communicate clearly and want a client-facing roleYou’re based in London, or already committed to relocating, and excited to work with the team in person in FarringdonYou feel like you’re never building fast enoughBonus: you’ve built and designed AI-powered products 🧭 Interview process The Process Moves In Days, Not Months Introductory call: background, motivation and mutual fitLive technical screen (30-mins): solving a TypeScript problem live in an IDE with one of our engineers. We optimize for speed and completeness over polish, and the interview is completed without AI toolsOn-site Interview: a full afternoon of coding, a system-design whiteboard and a product discussion with one of our PMsFinal Cultural Round: a final conversation about how you work, what motivates you and whether Junior is the right environment for youOffer: decisions are made collectively and quickly 🌵 Benefits Private health insuranceThird Space gym membershipDinner provided when working lateTeam lunch provided every day at the officeFrequent international off-sites, recently including Crete and Cancún If you’re excited to drive innovation at Junior, we’d love to hear from you!