Senior Frontend Engineer, AI Observability – Evals Platform

LangChain

. Develop new user-facing features for LangSmith, LangChain's enterprise platform for LLM application observability, testing, and debugging .

Posted 10/8/2026full-timeRemote • United StatesSenior💰 $180,000 - $240,000 per yearWebsite

Core Competencies

Role fit

Core Competencies

Use this summary to align your resume positioning with the role.

Demonstrates extensive front-end engineering experience with strong proficiency in React, JavaScript, and TypeScript. Capable of optimizing components for performance and collaborating effectively with cross-functional teams, including fullstack and backend developers.

Highest-signal resume keywords

ReactJavaScriptTypeScriptBabelWebpack

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills

Front-End EngineeringComponent OptimizationREST APIsComputer Science Fundamentals

Soft Skills

Strong Written CommunicationStrong Oral CommunicationOwnership MindsetSelf-Direction

Tools & Technologies

ViteNPMYarn

Industry Keywords

LLM Application ObservabilityTestingDebuggingAuthorization MechanismsJWT

Tech Stack

Tools & technologies

BabelJavaScriptReactTypeScriptWebpackYarn

About the role

Key responsibilities & impact

Develop new user-facing features for LangSmith, LangChain's enterprise platform for LLM application observability, testing, and debugging
Build reusable components and front-end libraries for future use
Translate designs and wireframes into high-quality code
Optimize components for maximum performance across web-capable devices and browsers
Collaborate with fullstack and backend developers and UX/UI designers to enhance usability

Requirements

What you’ll need

Extensive front-end engineering experience
Strong proficiency in React, JavaScript, and TypeScript
Hands-on experience with Babel, Vite, Webpack, NPM, and Yarn
Familiarity with REST APIs
Experience working closely with fullstack and backend engineers
Knowledge of modern authorization mechanisms, such as JWTs
Strong written and oral communication skills
Ability to explain technical concepts clearly and concisely to technical and non-technical stakeholders
Ability to thrive in a start-up, fast-paced environment
Ownership mindset and self-direction
Strong computer science fundamentals
Degree in computer science or a related field is ideal, not required

Benefits

Comp & perks

Medical coverage
Dental coverage
Vision coverage
Flexible vacation
401(k) plan
Meals on in-office days in the US
Variable compensation for relevant roles
Meaningful equity
Perks