Fullstack Engineer

Arlequin AI; Paris; On-site; EUR 50,000 - 75,000; Full time

Benefits offered by this job

BSPCE

Job summary

Arlequin AI in Paris is hiring a hands-on fullstack developer to contribute to both ingestion pipelines and frontend interfaces for the HUDEX platform. You’ll work with senior engineers and own features end-to-end, from backend data processing to UI components.

You should have 1–5 years of fullstack experience, strong TypeScript and React skills, and be comfortable with Node.js and ORMs like Drizzle or Prisma. English proficiency required.

Qualifications

• 1–5 years of fullstack experience.
• Strong command of TypeScript and a modern React ecosystem.
• Comfortable with a Node backend and ORM (Drizzle, Prisma or equivalent).
• A desire to understand architectural choices, not just execute.
• Professional English.

Responsibilities

• Contribute to both ingestion pipelines and data processing on the backend, and interfaces on the frontend.
• Take ownership of complete features end to end.
• Work alongside senior engineers who mentor you on architecture.

Skills

TypeScript

React

Node.js

Architecture curiosity

English

Tools

Drizzle/Prisma

Job description

About Arlequin

Arlequin is building the sovereign European alternative to Palantir: an AI platform capable of processing massive data volumes without bias, with high-impact use cases such as fighting disinformation. Founded in late 2024 by Hugo Micheron (researcher in geopolitics and systemic risk) and Antoine Jardin (CNRS research engineer).

~30 people, post-seed, Series A in progress. On-site in Paris.

The role

You’ll join a team of around ten people to contribute to both sides of the platform — ingestion pipelines and data processing on the backend, exploration and analysis interfaces on the frontend. Our product (HUDEX) enables non-technical analysts to interpret narrative dynamics across large-scale digital ecosystems. You’ll work alongside senior engineers who mentor you on architecture, and you’ll quickly take ownership of complete features from end to end.

Stack

• Frontend: React 19, TypeScript, Tanstack Router + Query, Vanilla Extract CSS

• Backend: Hono, Node 24, Drizzle ORM, PostgreSQL, OpenAuth

• Build & infra: monorepo npm workspaces + Turbo, Vite, Docker, Azure Container Registry

• Data : Python

• Tests & quality: Jest, ESLint, Prettier, strict TypeScript

What we’re looking for

• 1–5 years of fullstack experience

• Strong command of TypeScript and a modern React ecosystem

• Comfortable with a Node backend and ORM (Drizzle, Prisma or equivalent)

• A desire to understand architectural choices, not just execute

• Professional English

Bonus

• Already comfortable in a startup environment

• Mastery of agentic coding tools and code models

• Exposure to Python / AI

• Experience with harness coding / implementation

• Interest in emerging tools and paradigms

• Fast learning on TypeScript codebases

Process (~2 weeks)

1. Screening (15 min)

2. Fit interview (30 min)

3. Technical interview (1h)

4. Founder culture fit (45 min)

5. Reference calls

6. Offer

Package

• 50-75k€ + BSPCE

• On-site central Paris