CareerOS is a B2B2C career platform serving 100+ top MBA programs worldwide - including Oxford, INSEAD, London Business School, Georgetown, and Notre Dame - along with 30+ employers. We help 500K+ users land jobs they love. We're a small, high-output team based in Barcelona, operating with American startup intensity - we ship fast, own our decisions, and push each other to do great work.

We work in small squads, each owning their own area of the product end-to-end.

We're looking for a Senior Product Engineer who's strong on backend, comfortable owning infrastructure and ops, and can contribute to frontend when needed. You'll work across Node.js (our primary stack for new code), some legacy Go, and React/TypeScript on the frontend.

What you'll actually do

You won't just write APIs. You'll own systems end-to-end.

• Ship features across the stack - Primarily backend (Node.js, with some Go), but you'll touch React/TypeScript when needed. We're moving all new code to Node.js.
• Own infrastructure and ops - GCP, Terraform, CI/CD pipelines. You'll build and maintain the systems that keep us running.
• Optimize databases - Write and tune SQL, improve query performance, design schemas that scale.
• Make product decisions - See a better way to architect something? Propose it and build it. We trust engineers to make smart calls on technical and small-to-medium product decisions.
• Build with AI tools - We use AI coding tools daily (Claude Code, Cursor - team members pick what works for them). You should be comfortable (or excited) to work this way.
• Own your code in production - We do continuous deployment. What you merge today is live today. You'll debug, monitor, and improve what you build.

What we're looking for

Must-haves:

• 5+ years building production backend systems, with strong experience in Node.js or Go
• Solid SQL skills - You can write complex queries, optimize performance, and design schemas
• Infrastructure experience - GCP (or AWS), Terraform, CI/CD pipelines. You've built and maintained production infrastructure.
• Can work across the stack - You're backend-focused but can navigate React/TypeScript codebases and ship frontend changes when needed
• Strong product intuition - You've shipped features where you made architectural and product calls, not just followed tickets