Senior Backend Engineer

Senior Backend Engineer – Logistics, Payment & Invoicing (Berlin)

We’re CarOnSale—a Berlin-based startup on a mission to shake up automotive trading across Europe. We’re growing fast, building some seriously cool stuff, and we want you to help us create next-level B2B solutions with real impact.

Here’s what we’re hoping you’ll do with us:

• Build What Matters: Work super closely with product and design so we ship stuff that makes a real difference for our customers (and for the whole business).
• Think Big, Build to Last: Take the lead on designing and running backend systems. Distributed? High-volume? Need to scale or evolve? You’re the expert who makes it work (and keeps it working).
• Set the Bar High: Clean code, solid tests, systems that don’t go down in a stiff breeze—we want you to set the standards and keep us honest. Lead the tough architectural reviews, too!
• Let the Data Speak: You care if features really deliver. So you measure, you learn, you iterate—and you insist we don’t stop until we see results.
• Mentor, Teach, Repeat: Help others get better. Review code, guide junior folks, set the example for learning & ownership. Don’t just help the team—level up the team.
• From Idea to Production (& Beyond): Own your work, front to back. Ideate, design, launch, monitor—and fix/improve what’s needed. No unfinished business left in the backlog!
• Make Us Sharper: Bring better processes, contribute in planning, doc, testing, incident retros—you see something broken or slow, you fix it!
• Plug Us In: Build slick, safe integrations (like with Stripe and friends)—our backend should play nicely with the whole ecosystem.

Here’s what we’re looking for:

• Battle-Tested: 5+ years in backend, you’ve led big projects, owned distributed or microservice systems, and made architectural calls.
• Deep Tech Skills: TypeScript, Node.js, NestJS, PostgreSQL—these are your bread and butter. Plus: queues, caching, monitoring, system design—you know how all the pieces fit together.
• Results, Not Just Code: You don’t just deploy features; you care that they move the needle for the business or product. Show us how your work made a real impact!
• Mentor Mode On: Examples where you didn’t just deliver, but also helped others step up—across teams, in reviews, leading by example.
• Think Product, Think Customer: You connect what you build to what users and the business actually need.
• No Shortcuts on Quality: Automated tests, operational excellence, rollout discipline—you don’t cut corners.
• Great Communicator: You break down complex stuff for anyone (tech or not) and earn trust everywhere you go (in English).
• Learner & Challenger: You’re always growing, questioning, teaching—and you raise the bar for everyone around you.

Why you might love it here:

• Shape the Future: Your ideas actually matter (a lot). You’ll have real influence on where we go.
• 25 Days Work-From-Anywhere: Pack your laptop and go—you can work from wherever inspires you, for 25 days a year.
• Private Pension Plan: We help you plan for your future, right from day one.
• Deutschland Ticket: Get around the city (and beyond!) on us—you’ll always have a ride.
• VSOPS: Share in the success you help create with our Virtual Stock Option Plan.
• Autonomy & Support: You’ll steer things, but also get feedback and coaching to help you grow as a leader.
• Your Tech, Your Way: Mac or Windows? Up to you—we want to set you up for success.
• Superb Team Spirit: Ambitious, helpful colleagues, team events, and a truly collaborative vibe. We call it being a “COSie.”
• You Belong: We’re building an open, high-performing team—your perspective is needed and welcomed.

Sound interesting? Drop us a line. We’d love to meet you!