Shape the technical direction of LangSmith as a Senior Fullstack Engineer in a growth-stage AI company.
Posted by employer 1 month ago
First seen on Joblaze 1 month ago
Last verified on the company career page 11 hours ago
Skills & Technologies
What you'll build
- Lead technical architecture and implementation of key product features
- Collaborate with product and design teams
- Drive project timelines while ensuring engineering standards
- Write clean, maintainable, and well-tested code
Must have
- 5+ years of experience in software engineering
- Fullstack engineering experience with Go or Python and React + TypeScript
- Strong understanding of database systems, particularly PostgreSQL and Redis
- Experience designing and scaling APIs
Nice to have
- Experience with AI/LLM-powered applications
- Experience with developer tools
- Experience with observability platforms
Practical constraints
- Onsite 5 days/week in Boston, MA
Requirements
- Experience
- 5+ years
Not disclosed in this posting: visa sponsorship.
Benefits
Joblaze summary
In this role, the Senior Fullstack Engineer will lead the development of key features for LangSmith, focusing on the technical architecture and implementation across a Go, Python, and Typescript stack. The position requires extensive experience in fullstack engineering, particularly with backend systems and frontend frameworks, as well as a solid grasp of database management. Ideal candidates will have a strong ownership mindset and a collaborative approach, making this role suitable for seasoned engineers looking to impact AI observability at scale. The team is dedicated to defining high standards for production reliability in AI systems.
Joblaze insights
- Listed about a month ago — first seen on Joblaze September 12, 2026. Last confirmed on LangChain's careers page November 1, 2026.
- Salary band is in line with the typical range for Fullstack roles (median ~$165,000).
- Starts above 55% of 93 comparable senior fullstack roles in United States that list React we track (median $170,000 across 49 companies). See React salary trends
- React appears in 69.8% of 225 comparable senior fullstack roles in United States; Redis appears in 6.7% of 225 comparable senior fullstack roles in United States.
Quick facts
- Is the Senior Fullstack Engineer, AI Observability & Evals Platform role remote?
- No — this is an on-site role in Boston, MA.
- What's the salary range?
- LangChain lists $175,000–$240,000 for this role.
- How much experience is required?
- At least 5 years of relevant experience for this Senior Fullstack Engineer, AI Observability & Evals Platform role.
- Where is the role based?
- LangChain is hiring for this position in Boston, MA.
- What's the tech stack?
- Joblaze extracted these technologies from the posting: Go, PostgreSQL, Python, React, Redis, TypeScript.
- What seniority level is this role?
- LangChain targets senior candidates for this position.
- Is this full-time or contract?
- Full-time for this Senior Fullstack Engineer, AI Observability & Evals Platform role at LangChain.
From the original posting
About Us
About The Team
The LangSmith team owns and builds LangChain's core platform for observability, evaluation, and production reliability of AI systems. From tracing and annotation to run rules, evaluations, and beyond, this team owns LangSmith end-to-end. If you want to define what great AI observability looks like at production scale, this is where that work gets done.
About the role
This role is onsite 5 days/week in Boston, MA
We're looking for a Senior Fullstack Engineer to work on LangSmith. In this role, you'll have the opportunity to shape the technical direction of our platform while working closely with our enterprise customers, developer end-users, and cross functional internal stakeholders.
What You Will Do
Lead the technical architecture and implementation of key product features for LangSmith, working across our entire Go, Python, and Typescript stack.
Collaborate closely with product and design teams to iterate on new features.
Help drive aggressive project timelines while ensuring high engineering standards are being met.
Lead by example in writing clean, maintainable, and well-tested code.
What You Bring
5+ years of experience in software engineering working on complex platform products
Fullstack engineering experience with Go or Python on the backend and React + Typescript on the frontend.
Strong understanding of database systems, particularly Postgres and Redis
Experience designing and scaling APIs, preferably in a high-performance, data-intensive application
A “get stuff done” attitude - comfortable shipping fast and iterating based on user feedback
Strong communicator with the ability to collaborate closely with various internal stakeholders and engage directly with our top-tier customers
Strong ownership mindset
Bonus: Experience with AI/LLM-powered applications, developer tools, or observability platforms
Compensation
Annual salary range: $175,000-$240,000 USD
Standard company text repeated across LangChain's postings is omitted here.