Senior Backend Engineer (m/f/d) - Agent SDK

🎤 Why voize? Because we're more than just a job!At voize, we believe the greatest gift to frontline workers is time - time to care, connect, and be present. Today, that time is lost to busywork and complex systems that pull them away from what matters most: people.Our vision is to change that by building AI companions that seamlessly take over digital workflows. We don't replace humans with technology - we amplify their impact.Our mission is backed with a $50M Series A funding led by Balderton Capital, with support from HV Capital, Y Combinator and other leading VCs. Today, 2,000+ facilities trust voize, and over 200,000 users rely on our AI companion to ease their daily workload.As a dynamic team, we combine first-in-class technology with meaningful social impact. And now, we're looking for you to join us on this mission!💡 Your Mission: Build the layer every agent moves ontoAs Senior Backend Engineer on the team behind our Agent SDK, you build and maintain the Kotlin foundation that our AI agents move onto. Agents have grown into a product surface across verticals and markets, and the layer underneath them needs a permanent owner. Your work makes the cost of the second and third agents visibly less than the first, so feature teams can ship at their own pace.🚀 Your Daily Business - No two days are alikeBuild and maintain the SDK as an internal product. You shape the runtime and the client-facing contracts that consuming teams build on. The SDK has a roadmap of its own, and you help set it.You build the identity layer that agents run on, so customer-facing agents can write with a real user identity. Your responsibilities may include designing and shipping the auth plumbing, depending on what we have already built by your start date.Make every agent observable from the day it launches. You wire telemetry and error reporting into the SDK by default, and you integrate inference and anonymization so the SDK enforces them for every consumer.Build the test kit that the