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
• 150+ brand clients
• a $100B 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.