Senior Backend Engineer – Kotlin

Stellenbeschreibung:

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

Requirements

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

Core Competencies

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.