Senior Software Engineer (SDK)

About the Role This is a rare opportunity to own the SDK layer of a widely adopted open-source AI engineering platform — the kind of tooling that sits at the very first touchpoint developers have with the product. The SDKs you build ship to millions of downloads per month , running in production environments ranging from serverless functions to long-running agent loops. When you ship, thousands of developers benefit the same day. The bar is high: zero-failure reliability, minimal CPU and memory overhead, and idiomatic developer experience across Python and TypeScript. You'll be the person who sets that bar and upholds it. What You'll Do Own Python and TypeScript SDKs end-to-end — reliability, performance, and developer experience. You'll drive major version rewrites and architectural improvements, including work on OpenTelemetry-based tracing. Design APIs developers love — every detail of naming, parameter structure, breaking change communication, and documentation is yours to shape. Integrate with the AI ecosystem — build and maintain integrations with LLM frameworks, model providers, and agent runtimes; keep pace with a fast-moving ecosystem. Maintain and grow open-source community health — triage GitHub issues, review pull requests, engage with contributors, and communicate clearly on public channels. Drive performance — profile, benchmark, and optimize SDK footprint across latency, memory, and throughput dimensions. Own the release lifecycle — versioning strategy, changelog communication, compatibility testing, and CI/CD automation for library releases. Collaborate cross-functionally — work closely with product and data teams across EU timezones in a small, high-trust distributed team. What We're Looking For Required: 5+ years of professional software engineering experience, with at least 2 years building or maintaining SDKs or client libraries Proven track record designing, implementing, and maintaining production-grade SDKs — including API design, versioning,