About Us
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, and we're growing with real revenue (not just runway).
We're a small, high-output team of 5 engineers based in Barcelona, scaling to 10+. We work in small squads, each owning their area of the product end-to-end. We ship fast, own our decisions, and push each other to do great work.
The Role
We're looking for a Senior Product Engineer - someone who builds full features from database to UI, with strength in backend systems.
You'll work directly with the CTO and CPO, not through layers of management. You'll be in the room when decisions get made and have real input on what we build and how.
We call this a "Product Engineer" role because you won't just implement tickets. You'll own features end-to-end, make product calls, and ship things that matter to real users.
Tech stack: Node.js (primary for new code), some legacy Go (~20%),



React/TypeScript on frontend. Infrastructure on GCP with Terraform.
Typical split: ~60% backend/infra, ~40% frontend - varies by project.
What You'll Actually Do
- Ship full features, end-to-end - From schema design to API to UI. You'll own the whole vertical, not just one layer.
- Build and maintain infrastructure - GCP, Terraform, CI/CD pipelines. You'll keep the systems running and improve them over time.
- Optimize databases - Write complex queries, tune performance, design schemas that scale.
- Make product decisions - See a better way to solve a user problem? Propose it and build it. We trust engineers to make smart calls on technical and product decisions.
- Build with AI tools - We use Claude Code, Cursor, and other AI tools daily. You should be comfortable (or excited) to work this way.
- Own your code in production - Continuous deployment means what you merge today is live today. You'll debug, monitor, an

📌 Senior Product Engineer (Barcelona)
🏢 Careeros
📍 Barcelona