Lead Product Engineer

This role is with one of Dex's trusted partner companies. We work closely with their teams to truly understand their culture, goals, and what they're looking for, so we can match you with the right opportunity and give you context about the role before you commit to a process. If you're interested sign up to Dex to apply. Dex is an AI recruiter agent that helps you run your job search. Tell Dex your stack, seniority, and what you want to build. We will manage your applications and surface other opportunities that are a fit. The role A company building large-scale simulated populations of AI personas, grounded in real-world behavioural data. They enable Fortune 500 organisations to test messages and strategies against audiences traditional research can't reach. Backed by leading VCs, they're seeing significant ARR and strong traction. This is their first lead-level product engineering hire. You'll own features end-to-end, from front-end interaction to database, working directly with the designer and CTO. This isn't a siloed feature-factory role; you'll make architectural calls that shape the product for years, while also sweating the small interactions that define user experience. You'll set the engineering standard as the team grows, building a product where reliability is non-negotiable for high-stakes client decisions. The work Own the full vertical slice of new features, from initial scope and design through to shipping and iteration across front-end, API, and database.Define system architecture, data models, and API contracts that will underpin the product's evolution for years.Obsess over user experience: from browser rendering performance and API latency to caching, concurrency, and queueing.Collaborate with research and forward-deployed engineers to productise frontier AI capabilities into client-facing features.Establish and uphold the engineering bar for system design and code quality as the team scales. What You Bring 5+ years shipping production software, owning features end-to-end, and a track record as the go-to engineer for complex problems.Expert in TypeScript, comfortable across the full stack, and productive in Python.Deep understanding of system performance across the stack: browser, API, caching, concurrency, and advanced Postgres skills (indexing, query planning, migrations).Experience designing scalable architecture: defining service boundaries, making build-vs-buy decisions, and establishing robust API contracts.Proficiency with AI coding agents (e.g., Claude Code, Codex) to accelerate development while maintaining high quality standards. Why apply through Dex This is a rare lead-level role at a company building frontier AI simulation products. Skip the noise of cold applications and get a direct introduction. Dex briefs you thoroughly, ensuring you understand the full context and opportunity before you even interview. If you're interested, sign up to Dex to apply - https://jobs.meetdex.ai/jobs/6ed461e4-c225-4446-848a-cc86ce456c59 As part of the recruitment process at Dex, we process your personal data in accordance with our Privacy Notice for Job Applicants. This notice explains how and why your data is collected and used, and how you can contact us if you have any concerns.