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Working Student – Backend Developer & Data Detective

Advertising Solutions

Working Student

Hamburg

adjoe builds the technologies behind mobile apps growth and monetization. With our core product Playtime Arcade, we’ve become the global leader in rewarded advertising, an ad unit built on a simple premise: users earn real in-app rewards for engaging with new apps. The result is one of the most effective value exchanges in adtech, connecting advertisers and publishers with over 770 million users annually.

Running the Engine Behind 200M+ Daily Ad Decisions

Behind every ad decision at adjoe is a system designed to operate at massive scale, serving more than 770 million mobile users every year. The Demand API Integrations team owns the systems that connect our platform to the global adtech ecosystem, handling over 5.5 billion API requests daily across installs, events, views, clicks, and postbacks from Mobile Measurement Partners.

We operate a dedicated A/B testing environment against live traffic to validate system behavior under real-world conditions, allowing us to evaluate advertiser integrations, benchmark partner performance, and verify attribution accuracy end-to-end before deploying globally.

We integrate TensorFlow-based ML models to predict user engagement and purchase likelihood, directly influencing real-time ad distribution. To meet our strict 100ms latency constraint, we prioritize efficient model serving, low-latency data access, and deliberate system design.

Your Mission & Who We Are Looking For:

Backend foundation with a data mindset. You’re currently studying Computer Science, Data Science, or a related field, with hands-on experience in at least one backend language — Node.js, C#, or Java — and a genuine interest in picking up Go. You have strong SQL skills covering joins, aggregations, and query optimization, and you’re comfortable with relational databases like PostgreSQL or MySQL.
You have projects to show, not just coursework to list. You have a track record of past projects you can walk through and discuss — what you built, why, and what you’d do differently. At adjoe, you’ll be contributing to real backend services and data pipelines from day one, not writing throwaway code.
Comfortable in a modern engineering stack. You understand REST APIs, Git, and CI/CD pipelines, and have some familiarity with cloud platforms like AWS, GCP, or Azure. You’ll be working alongside experienced engineers who review your code and expect you to grow from that feedback.
Analytical and detail-oriented. You enjoy data-driven problem solving as much as writing code — helping improve data quality, validation, and monitoring processes, and collaborating with BI and data teams to deliver insights that matter.

What’s in It for You?

At adjoe, you’re not here to just close JIRA tickets, you’re helping build the infrastructure behind one of the most impactful platforms in adtech. The systems you work on will reach hundreds of millions of users and power billions of decisions every day.

Go Big. Own projects with impact on 770M users and push adtech boundaries.
Move Fast. Ship solutions multiple times a day, learn from results, and keep momentum.
Be Direct. Solve problems openly and collaborate across teams.
Thrive Together. Grow with a diverse, global team of people from over 40 different countries that learn from each other.
Have Fun. Celebrate wins, enjoy daily victories, and bring your energy.

Skip writing cover letters. Tell us about your most passionate personal project, your desired salary and your earliest possible start date. We are looking forward to your application!

We welcome applications from people who will contribute to the diversity of our company.