Senior Android Developer (f/m/d)

About adjoe

adjoe builds the technologies behind mobile apps growth and monetization. adjoe Ads is our programmatic in-app advertising platform that seamlessly connects advertisers and publishers through direct integration of our Android and iOS SDKs. Every ad decision happens in under 200ms across 10 million daily users, powered by real-time bidding algorithms and user quality prediction models.

Where 50 Billion Daily Predictions Begin

The User Experience team is the origin point of adjoe Ads. On the SDK side, native Kotlin and Swift code runs inside hundreds of publisher apps, participating in 120 million daily auctions, rendering ad creatives, and capturing behavioral signals that power 50 billion predictions per day. On the analytics side, dashboards and data frameworks turn raw data into decisions.

Your Mission

• Kotlin & Android Internals Expertise: Own the core development and optimization of the adjoe Ads SDK, which runs inside hundreds of publisher apps. 8+ years of Android experience (or 3+ years specifically in SDK/library development), working primarily with Kotlin, with deep understanding of Android lifecycles, ProGuard/R8, and multithreading
• High-Performance Network Design: Collaborate with backend teams to design APIs and capture behavioral signals that power 50 billion daily ML predictions, with a strong track record in API design and high-performance networking protocols like gRPC, Protobuf, Wire, and OkHTTP
• Resource-Constrained Optimization: Design for minimal footprint, optimizing battery impact and memory usage
• Data-Driven Observability: Monitor, debug, and maintain SDK reliability at scale using Sentry, Kibana, and AWS (S3, QuickSight, Athena)
• Build Automation & Delivery: Maintain and improve CI/CD pipelines using Gradle and GitLab CI

Plus: Experience in ad-tech or programmatic advertising (IAB specifications); experience with NDK/JNI (C/C++ interop on Android) or parallel iOS development.

Location

We welcome applications from talent worldwide and provide relocation support to Hamburg, Germany for those ready to join the team.