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Salary: USD 185,000 - 240,000 / annual
LangChain is hiring a Platform Software Engineer to own the ingestion, query, and API systems at the core of LangSmith, their observability and production reliability platform for AI systems. You'll design and operate high-throughput, data-intensive ingestion and trace-query systems built on SmithDB, a purpose-built database for agent observability. The role spans distributed systems, developer experience, and infrastructure at scale.
Key responsibilities include: building and scaling critical ingestion and query systems with monitoring, alerting, and automated recovery; defining and enforcing API, SDK, and CLI standards across Python, TypeScript, Go, and Java; owning integrations to keep LangSmith framework-agnostic; debugging performance bottlenecks and optimizing database queries; and participating in on-call rotation with a focus on post-incident learning and prevention.
You should have hands-on experience designing and running data-intensive systems at scale, a track record building high-quality developer-facing CLIs, SDKs, or APIs, and production experience with open-source datastores like PostgreSQL and Redis. Strong backend software engineering skills in Go, Python, or TypeScript are essential. You'll need solid knowledge of cloud infrastructure (GCP, AWS), Kubernetes, containerized systems, and observability stacks (Datadog, Prometheus/Grafana, OpenTelemetry). An operational mindset with high agency—"you build it, you run it, you own it"—is critical.
Nice-to-haves include experience building production systems or developer-facing APIs, strong Java experience, knowledge of columnar file formats and OLAP databases, and background in high-growth startups. LangSmith serves 6,000+ active customers and 35% of the Fortune 500, including Klarna, Coinbase, Workday, and Nvidia. The company raised $125M at Series B from top-tier VCs and is accelerating product development and growth.
About LangChain
AI / Data / Infrastructure — developer platform and framework for building LLM applications and agents.
