Senior Fullstack Engineer, AI Observability & Evals Platform

LangChain
Boston, New York
Workplace: OnsiteFull timeUSD 175,000 - 240,000 annuallyFunction: Software EngineeringExperience: 5+ yearsSkills: ["Ownership","Collaboration","Communication","Shipping fast","Iterative improvement"]

Build LangSmith’s core AI observability and evaluation platform, shaping technical direction while collaborating with enterprise customers and cross-functional teams. Own the architecture and implementation of key product features end-to-end across Go, Python, and TypeScript/React. Design scalable, high-performance APIs and work with Postgres and Redis. Contribute clean, maintainable, well-tested code and help drive aggressive timelines without sacrificing engineering quality.

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FursaFursa
LangChain
LangChain
6 hours ago

Senior Fullstack Engineer, AI Observability & Evals Platform

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Source: Company careers pageValidated by: Fursa AI
Last checked: 1 hour agoStatus: Live

Job Summary

Build LangSmith’s core AI observability and evaluation platform, shaping technical direction while collaborating with enterprise customers and cross-functional teams. Own the architecture and implementation of key product features end-to-end across Go, Python, and TypeScript/React. Design scalable, high-performance APIs and work with Postgres and Redis. Contribute clean, maintainable, well-tested code and help drive aggressive timelines without sacrificing engineering quality.
Location: Boston, New York
Workplace: Onsite
Employment Type: Full time
Job Function: Software Engineering
Seniority: Mid level

Key Responsibilities

  • •Lead technical architecture and implementation of key LangSmith product features across the full stack.
  • •Collaborate with product and design teams to iterate on new features.
  • •Drive aggressive project timelines while maintaining high engineering standards.
  • •Lead by example writing clean, maintainable, and well-tested code.
  • •Work closely with enterprise customers and internal stakeholders to shape the platform’s technical direction.

Pay and Benefits

Salary: USD 175,000 - 240,000 annually
Equity and Bonus:Equity
Perks:Health InsuranceDentalVision401kPaid LeaveMeal Allowance

Key Requirements

  • •5+ years of software engineering experience building complex platform products.
  • •Fullstack experience using Go or Python (backend) and React with TypeScript (frontend).
  • •Strong understanding of database systems, especially Postgres and Redis.
  • •Experience designing and scaling APIs, preferably in a high-performance, data-intensive application.
  • •Ability to collaborate closely with product, design, and stakeholders, with a strong ownership mindset.
Experience:5+ yearsPlatform productsAI/LLM-powered applicationsObservabilityDeveloper tools
Skills:OwnershipCollaborationCommunicationShipping fastIterative improvement
Tech Stack:GoPythonTypeScriptReactPostgresRedis

Company Brief

LangChain
Provides an open-source framework and commercial platform (LangSmith/LangGraph) for building, testing, monitoring, and deploying LLM-powered applications and agentic AI for developers and enterprises.
Industry: Developer Tools
Company Size: Medium (51 to 250 employees)
Revenue: USD 10M to 25M
Growth: Scaleup
Valuation: Unicorn (USD 1B+)
Funding: Series B
Headquarters: San Francisco, United States
Founded: 2022
WebsiteLinkedIn