Full-Stack AI Engineer

About Influentials

Influentials is a creator marketing platform and managed service built to help brands scale creator content. More than 16,000 creators are directly connected and verified on our platform, and more than 500 brands, including McDonald's, Disney, Samsung, ALDI and Volvo, have run over 5,000 campaigns with us. We're headquartered in Rotterdam, Netherlands and building our tech hub in Marseille, France.

How we build

AI is both how we build and what we build. We practise agentic engineering on a modern TypeScript stack: AI agents write most of the code, and humans specify and review everything that goes live. We merge hundreds of PRs each month, and our velocity keeps accelerating. We're not tied to one tool (Claude Code today, Codex before), and we adopt new practices as they land, like cloud coding agents and agent loops. The job is changing fast right now, and you'll learn it with us.

Over the coming months, we're building what comes next for brands and creators, and we're looking for a full-stack intern to build it with us.

What you'll work on

This is an internship: you're here to learn. You'll work alongside the CTO and contribute to real features in production, used by thousands of creators and by brands. Depending on timing and what you enjoy, that can include:

• AI agents that run campaigns. Agents that propose a shortlist of creators, draft the brief and follow up with creators, while a campaign manager approves each step. We already have a creator-review agent in production and a cockpit to track what agents do and what they cost.

• The brand app. New features for brands in our Next.js app, including an AI assistant that helps a brand write its campaign brief.

• A Claude connector (MCP) for brands. Brands connect Claude to their Influentials account and ask questions about their campaigns. The same architecture already runs internally: our whole team uses Claude on top of the Hub every day.

• The mobile app (Expo / React Native). Push notifications, live messaging and the first store releases.

• Scraping social platforms. Scrapers that collect public creator profiles and their content at scale, and the pipelines that clean and store that data.

• Creator analytics. Our own AI analysis of what creators publish (themes, brand safety, brand affinity), built into an in-house analytics tool.

With the CTO's support, you'll take part in every step of a feature: spec, code, tests, review, release, then watching it in production with Sentry and PostHog. This is AI engineering, not machine learning: agents, AI features, tools, prompts and evals built on top of existing LLMs. No model training.

Who you'll work with

You'll work directly with Matthieu, our CTO, in Marseille: specs, code reviews and architecture discussions, every day. Matthieu cares as much about business and product as about code, so you'll also learn why we build what we build. The rest of the team is in Rotterdam: weekly video calls with sales, campaign management and product, in English, with no travel needed. You'll be one of the first people in our Marseille tech hub, with a real scope and someone next to you to help you get there.

Stack

• Frontend: TypeScript · React 19 · Next.js 16 (App Router, Server Components) · Tailwind / shadcn/ui

• Backend: tRPC · Zod · Prisma · MySQL 8.4 on AWS RDS

• Background jobs: Inngest (durable workflows, crons, fan-out)

• AI: LLM APIs through the Vercel AI SDK · MCP servers

• Mobile: Expo / React Native

• Payments & auth: Stripe Connect · Better Auth

• Infra: pnpm + Turborepo monorepo · Vercel · AWS (RDS, S3, EC2) · Docker · GitHub Actions CI

• Quality & observability: Vitest · Sentry · PostHog

• Tooling: Claude Code · Codex · GitHub · Linear

Plus a legacy PHP API that we're migrating to TypeScript, piece by piece.

Who we're looking for

• A final-year student (Master's or engineering school) in computer science / software engineering, looking for a 6-month internship: end-of-studies internship, or an internship abroad as part of your degree.

• You've built and shipped things with TypeScript and Node.js, plus React or another JavaScript frontend framework such as Vue or Angular: school projects, side projects, open source or a previous internship. Show us.

• You already use AI coding tools, and you have opinions on when not to trust them.

• You read code carefully. Writing code is fast now; judgement and quality are the skills that matter.

• You're comfortable working in English (weekly calls with the Rotterdam team). Day to day in Marseille, we speak French or English, whichever you prefer.

Nice to have: React Native / Expo, SQL, experience with LLM APIs or agents, a project with real users.

Don't tick every box? Apply anyway.

Practical details

• 6 months, starting between December 2026 and February 2027

• Based in a coworking space in Marseille, with a sea view. Flexible hybrid: around 2 days of remote work a week. We care about what you ship, not the hours you spend at your desk.

• Internship agreement with your university (convention de stage)

• Students from other EU countries welcome, including Erasmus+ traineeships. If you've always wanted to spend six months by the Mediterranean, this is a good excuse.

How we hire

1. A 15-minute call with Matthieu, our CTO, to get to know each other.

2. A 30-minute technical interview.