Senior Backend Engineer – Kotlin

• Build and maintain the Kotlin Agent SDK as an internal product
• Shape the SDK runtime and client-facing contracts
• Help define the SDK roadmap
• Build the identity layer and authentication plumbing for agents
• Integrate telemetry, error reporting, inference, and anonymization into the SDK
• Create the SDK test kit and architecture tests
• Build integration with the ML team's evaluation harness before model changes ship
• Own Koog version upgrades and format compatibility
• Define shared limits for tool output and token usage
• Support consuming engineering teams by absorbing ecosystem changes

• Several years building production backend systems in Kotlin, including systems consumed by other engineers
• Experience building an SDK or internal platform where the published contract is the product
• Experience with versioning work associated with consumed SDKs or platforms
• Experience setting up testing and observability tooling
• Interest and familiarity with AI agent systems, orchestration, and evaluation
• Clear communication in English
• Proficiency in Kotlin and Coroutines
• Excellent fluency in English
• Legal right to work in Germany
• Based in Berlin, willing to relocate to Berlin, or seeking remote work within Germany
• Remote work within Germany requires travel to Berlin every 3 months for work-weeks

Demonstrates expertise in building and maintaining SDKs, particularly in Kotlin, with a focus on backend systems and integration of observability tooling. Proficient in defining product contracts and managing versioning for internal platforms.

• Kotlin Development
• SDK Development
• Versioning Management
• Testing and Observability Tooling
• AI Agent Systems Familiarity

• Kotlin
• Coroutines
• Backend Systems Development
• SDK Architecture
• Integration Testing
• Telemetry Integration
• Error Reporting
• Anonymization Techniques
• Version Control
• Contract Definition

• Clear Communication

• AI Agent Systems
• Orchestration
• Evaluation Harness
• Ecosystem Changes
• Remote Work