Sr. Software Engineer, Agents

Plug Technologies Inc; Los Angeles (CA); On-site; USD 175,000 - 200,000; Full time

Benefits offered by this job

Health insurance

Vision insurance

Dental insurance

401(k) plan

Lunch stipend

Equity

30-day remote work from anywhere

Unlimited PTO

Fully stocked kitchen

Dog-friendly office

Growth opportunities

Job summary

Plug is seeking a Sr. Software Engineer to build and deploy agents and multi-agent workflows for operations, dealers, and sellers. You’ll leverage LangChain, LangGraph, and LangSmith/Langfuse to create reliable, eval-driven features that scale across the platform.

You’ll ship across the stack, from backend services and APIs to TS/React interfaces for reviewing agent outputs, while maintaining observability and robust guardrails.

Qualifications

• 5+ years of full-time industry software engineering, with a track record of shipping features to production.
• Strong TypeScript or Python, and comfort across the stack: APIs, databases, and frontend when needed.
• Hands-on experience building LLM features in production: tool use, retrieval, structured output, and evaluation.
• Experience with an agent framework and observability stack, ideally LangChain, LangGraph, LangSmith, or Langfuse.
• You work agent-first and have built tooling around coding agents.
• Comfort building inside systems designed by others and shipping agreed plans.
• Habit of writing design notes, eval results, and runbooks for others.
• Enjoy collaborating in a small team and shipping with high autonomy.
• BS in computer science or a related field, or equivalent experience.

Responsibilities

• Build and ship agents and multi-agent workflows for operations, dealers, and sellers: document extraction, inspection and title review, dealer and seller communication, and internal tooling.
• Use LangChain and LangGraph to build agents, and LangSmith or Langfuse to trace, debug, and evaluate them.
• Write evals, build datasets from real cases, measure accuracy and failure modes, and make regressions visible.
• Integrate agents with the services the team already owns, through clean APIs and tools.
• Monitor agents in production: cost, latency, error rates, and human-review rates. Fix what breaks and tighten prompts, tools, and guardrails over time.
• Ship full-stack when needed: TypeScript and React screens and the backend endpoints behind them.
• Help the rest of engineering adopt the same patterns. Build reusable tools, examples, and runbooks.

Skills

TypeScript

Python

APIs

Frontend

LLM features production

Agent frameworks

Education

BS in Computer Science or related field

Tools

LangChain

LangGraph

LangSmith

Langfuse

Job description

Job Title: Sr. Software Engineer, Agents

Team: Engineering

Location: Onsite - Sawtelle (Between Santa Monica & West LA)

Employment Type: Full-time, Salary, Exempt

Reports To: Head of Engineering

About Plug

Plug is the marketplace for used electric vehicles. Consumers get an instant cash offer backed by battery-health data, and dealers across the US bid in real time on that inventory. Former Tesla executives founded Plug in 2023. We’ve raised a $20M Series A led by Lightspeed Venture Partners.

Why Plug

• You’ll help build the biggest infrastructure opportunity in automotive.

• You’ll work on a platform built exclusively for EVs, with nothing adapted from legacy automotive.

• You’ll work directly with operators who have scaled multi-billion dollar businesses in automotive, EV, and marketplaces.

• You’ll ship constantly, with high autonomy and a direct line to company outcomes.

The Opportunity

Plug runs on a lot of manual work: reading titles and inspection reports, chasing paperwork with dealers, checking vehicle details, answering sellers, and moving each car from offer to sale. Much of that work can be done by agents. We already run LLM features in production, and our engineers own the core platform: the marketplace, pricing, and the systems that tie them together. What we need now is someone who can turn a stream of real operational problems into agents that work reliably, one after another.

What You’ll Do

• Build and ship agents and multi-agent workflows for operations, dealers, and sellers: document extraction, inspection and title review, dealer and seller communication, and internal tooling.

• Use LangChain and LangGraph to build agents, and LangSmith or Langfuse to trace, debug, and evaluate them.

• Write evals, build datasets from real cases, measure accuracy and failure modes, and make regressions visible.

• Integrate agents with the services the team already owns, through clean APIs and tools. Work within the existing architecture and raise design concerns with the owning engineer instead of routing around them.

• Monitor agents in production: cost, latency, error rates, and human-review rates. Fix what breaks and tighten prompts, tools, and guardrails over time.

• Ship full-stack when the job calls for it: the TypeScript and React screens where people review and correct agent output, and the backend endpoints behind them.

• Help the rest of engineering adopt the same patterns. Build reusable tools, examples, and short write-ups that make the next agent faster to build.

What You’ll Bring

• 5+ years of full-time industry software engineering, with a track record of shipping features to production and supporting them after launch.

• Strong TypeScript or Python, and comfort working across the stack: APIs, databases, and frontend when needed.

• Hands-on experience building LLM features in production: tool use, retrieval, structured output, and above all, evaluation.

• Experience with an agent framework and observability stack, ideally LangChain, LangGraph, LangSmith, or Langfuse. If you’ve used something else, show us what you built and how you knew it worked.

• You work agent-first. You’ve built your own tooling around coding agents, such as skills, MCP servers, custom workflows, or evals.

• Comfort building inside systems other people designed. You can disagree, make your case, and then ship the agreed plan.

• A habit of writing things down: short design notes, eval results, and runbooks that others can pick up.

• You enjoy being part of a small team: pairing, reviewing each other’s work, and sharing credit.

• High agency in an ambiguous, fast-moving startup. You find the most valuable workflow to automate and ship against it without waiting for a perfect spec.

• BS in computer science or a related field, or equivalent experience.

Nice to Have

• Experience with document-heavy workflows such as titles, registrations, inspections, lending, or insurance.

• Experience with vehicle, marketplace, or auction products.

• Experience with human-in-the-loop review tools, or with fine-tuning and prompt optimization for production LLM features.

Compensation and Benefits

Annual salary: $175,000 to $200,000

Salary ranges come from independent, third-party benchmarking against national compensation data. Where an offer falls within the range depends on relevant experience, specialized skills, training and qualifications, current business needs, and market conditions. We review ranges periodically and may adjust them as the market changes.

Benefits & Perks

• Health, Vision, and Dental insurance

• 401(k) plan

• Daily lunch stipend

• Equity (based on role and performance)

• 30-day remote work from anywhere policy

• Unlimited PTO

• Fully stocked kitchen

• Dog-friendly office

• Ongoing opportunities for growth and development

This full-time position is an in-person role based in Sawtelle (between Santa Monica and West Los Angeles). Relocation assistance will not be provided for successful candidates. Sponsorship not available at this time.

Acknowledgments

Plug is an equal opportunity employer. We don’t discriminate on the basis of race, color, religion, creed, national origin, ancestry, sex, gender, gender identity or expression, sexual orientation, pregnancy, age, marital status, military or veteran status, physical or mental disability, medical condition, genetic information, or any other characteristic protected by law. Plug will consider qualified applicants with arrest and conviction records in accordance with the Los Angeles Fair Chance Initiative for Hiring and the California Fair Chance Act.