Senior Software Engineer (SDK)

Langfuse
Zurich, Munich, Paris, Berlin, London
Workplace: HybridFull timeEUR 90,000 - 160,000 annuallyFunction: Software EngineeringSkills: ["Developer experience focus","API design","Project ownership","Versioning thinking","Open-source collaboration"]

Own Langfuse’s Python and TypeScript SDKs built on OpenTelemetry, ensuring reliability and minimal CPU/memory overhead across environments. Design developer-loved APIs, maintain integrations with major AI frameworks and model providers, and keep the OTLP endpoint robust and well-documented. Write public SDK documentation and migration paths while improving performance, error handling, and versioning. Ship open-source work with visible impact to millions of SDK downloads.

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FursaFursa
Langfuse
Langfuse
5 months ago

Senior Software Engineer (SDK)

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Source: Company careers pageValidated by: Fursa AI
Last checked: 8 hours agoStatus: Live

Job Summary

Own Langfuse’s Python and TypeScript SDKs built on OpenTelemetry, ensuring reliability and minimal CPU/memory overhead across environments. Design developer-loved APIs, maintain integrations with major AI frameworks and model providers, and keep the OTLP endpoint robust and well-documented. Write public SDK documentation and migration paths while improving performance, error handling, and versioning. Ship open-source work with visible impact to millions of SDK downloads.
Location: Zurich, Munich, Paris, Berlin, London
Workplace: Hybrid
Employment Type: Full time
Job Function: Software Engineering
Seniority: Mid level

Key Responsibilities

  • •Own and maintain Langfuse SDKs in Python and TypeScript built on OpenTelemetry, focusing on reliability, performance, and developer experience.
  • •Design and evolve SDK APIs, including error handling, batching, async flushing, graceful degradation, and clear developer-facing documentation.
  • •Integrate and maintain compatibility across 40+ AI frameworks and model providers, adding new integrations as the ecosystem evolves.
  • •Maintain the OpenTelemetry OTLP endpoint path, ensuring it is robust, well-documented, and supports the full range of Langfuse features.
  • •Write public SDK documentation, integration guides, and migration paths, shipping docs alongside SDK and integration releases.

Pay and Benefits

Salary: EUR 90,000 - 160,000 annually
Equity and Bonus:Equity

Key Requirements

  • •Experience building or maintaining SDKs, client libraries, or developer tools, ideally in Python and/or TypeScript.
  • •Strong performance engineering skills, including profiling and benchmarking to minimize CPU/memory overhead in hot paths.
  • •Ability to manage projects independently, with strong judgment on what to build and how to ship.
  • •Thoughtful approach to versioning, backwards compatibility, and migration paths.
  • •Interest in open source software and communicating with developers about integration challenges.
Skills:Developer experience focusAPI designProject ownershipVersioning thinkingOpen-source collaboration
Licenses:MIT
Tech Stack:PythonTypeScriptOpenTelemetryOTLPNext.jsExpressPostgreSQLClickHouseS3RedisJavaGoLinearOpenAI SDKVercel AI SDKAI SDKLangChainLlamaIndexPydantic AIOpenAI Agents

Company Brief

Langfuse
Provides an observability and analytics platform for large language models and AI applications, enabling teams to track, debug, and improve model outputs, prompts, and user interactions across deployments.
Industry: Developer Tools
Company Size: Small (11 to 50 employees)
Growth: Early Stage Startup
Funding: Seed
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