Senior Go Backend Developer (Catalog) (f/m/d)

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.

**Serving 2,000+ Distinct Ad Experiences With Sub-Second Time to Interactive**

The rewarded ad experience is where the value exchange becomes real, the second a user decides whether to engage or scroll past. The Catalog team owns that moment, designing how users discover and interact with the most relevant ads. With **over 200 million monthly visits**, there's no room for slow rendering or poor personalization. Performance and relevance have to be perfect on every request.

The system runs on **AWS Spot Instances** spare compute capacity that can disappear at any moment, yet our system is built to stay online without any interruption for the user. Backed by **Kubernetes** with event-driven autoscaling, everything is tuned for millisecond-level data retrieval so the experience never feels slow, even at **200 million monthly visits**. The frontend is built on **React** and **Vite**, leveraging Code Splitting and Tree Shaking to keep core bundles lean and Time to Interactive under a second. On top of that, a config-driven engine lets the team customize the entire ad experience or run **A/B experiments** per **more than 2000 games** on the fly, ensuring the right ad reaches the right user while continuously moving conversion rates in the right direction.

• You will build and maintain our +99% Go microservice architecture—interfacing with our TypeScript/React frontend—to reliably handle 2+ million daily publisher interactions and scale beyond hundreds of millions of monthly active users.
• You will build pipelines to collect billions of daily API events and aggregate them into our data lake for sub-second querying.
• You will optimize queries across hundreds of terabytes of data across DynamoDB, MySQL, Druid, and Athena to reduce API response times and expose transparent, well-documented open APIs to enterprise partners.
• You will partner directly with our Data Science team to translate and integrate machine learning algorithms into adjoe's core application, optimizing real-time ad targeting.
• You will actively participate in peer code reviews and technical knowledge sharing across an international backend engineering team.

• 5+ years of backend development experience, including at least 3 years writing Go in production distributed environments
• Hands-on experience designing asynchronous microservice communication using event buses like Kafka, SQS/SNS, and Kinesis
• Understanding of database internals and low-level web standards (HTTP protocol, Encoding, Regular Expressions)
• Ability to quickly grasp complex technical topics and applied mathematics
• Fluent and precise communication in spoken and written English
• Hands-on experience with Terraform (Infrastructure as Code), Docker containerization, or serverless infrastructure

• Own projects with impact on 770M users and push adtech boundaries
• Ship solutions multiple times a day, learn from results, and keep momentum
• Solve problems openly and collaborate across teams
• Grow with a diverse, global team of people from over 40 different countries that learn from each other
• Celebrate wins, enjoy daily victories, and bring your energy
• Relocation support to Hamburg, Germany for those ready to join our team