Founding Full-stack Software Engineer

Who we are Lemrock builds the infrastructure of agentic commerce. Tomorrow, consumers won't just buy on e-commerce websites. They will discover, compare and purchase directly inside conversational AI interfaces like ChatGPT, Perplexity, and a growing long tail of specialized AI assistants. For brands, this is a major shift: if they are not present in these environments, they become invisible. Our mission: enable any brand to exist, sell and distribute in this new channel. We raised a €7M seed round (the first in Europe on this market), with Jean-Baptiste Rudelle, founder of Criteo, on our board, and the Bpifrance DeepTech label. Today, Lemrock is already: 100M conversations per month ~100 brand clients first significant revenues, with clients renewing a market structuring at high speed Context You'll join a small, high-ownership engineering team building production systems that serve millions of users. We care deeply about code quality and clean architecture — and we intend to keep it that way as we scale. Your Mission Your goal is to build and ship the product that powers Lemrock's commerce infrastructure — with full ownership, from design to production. Concretely, you will: Ship features end-to-end that reach millions of users — from data model and API design to the interface they interact with. Scale and harden our backend as traffic, integrations, and product complexity grow. Shape the architecture of the codebase — enforce clean boundaries, maintain modularity, and make decisions that compound as the team scales. Move fast across the stack — backend, frontend, infra, data — wherever the highest-impact work is on any given week. Candidate Profile Strong academic background, proven professional track record, or hands-on entrepreneurial experience 2+ years of hands-on software engineering experience Deep proficiency in TypeScript Experience with structured backend architectures (DDD, hexagonal, or similar) Has owned features end-to-end: data model → API → frontend → deployment Comfortable with AI coding tools (Cursor, Claude Code) Thrives in ambiguity and 0-to-1 environments — ex-founders or entrepreneurial mindsets are a strong fit Professional proficiency in French & English Tech Stack Core (required) TypeScript, NestJS, React PostgreSQL, Redis Docker Clean architecture patterns (hexagonal, ports & adapters) Bonus (appreciated but not required) GCP (Cloud Run, Pub/Sub, BigQuery), Terraform Vector databases, embeddings, LLM integrations Domain-Driven Design (DDD), CQRS TanStack (Router, Query, Table), shadcn/ui, Tailwind, Vite Durable workflows (Inngest, Temporal) Why Join Us Join a company in early breakout mode , already generating revenue, with a clear technological edge and strong financial backing to fuel its growth Work directly with an experienced team : two repeat YC founders who've scaled product & tech before, a former strategy/innovation director (10 years in the sector), and ex-strategy consultants (McKinsey QuantumBlack, BCG) Be part of the next structural shift of the web — agentic interfaces Own mission-critical topics , grow fast, and shape the company's future trajectory Package Competitive salary + equity, disclosed during the interview process.