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

• 4+ 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.