Sr. Software Engineer, Agents

Plug Technologies Inc•Los Angeles, CA

7d•$175,000 - $200,000•Onsite

About The Position

Plug is hiring a Sr. Software Engineer, Agents to turn real operational problems into reliable agents and multi-agent workflows. Plug is a marketplace for used electric vehicles where consumers receive instant cash offers backed by battery-health data and dealers bid on inventory in real time. Founded in 2023 by former Tesla executives, the company has raised a $20M Series A led by Lightspeed Venture Partners. The role focuses on automating manual work across vehicle transactions, including document processing, dealer and seller communication, vehicle-detail checks, and internal operations. The engineer will build on Plug’s existing production LLM features and core platform, integrating agents with existing services and working within the established architecture. The position also includes measuring and monitoring agent performance, supporting human review, and contributing reusable patterns and guidance for the broader engineering team. This is a full-time, salaried, exempt, in-person role based in Sawtelle, between Santa Monica and West Los Angeles. The position reports to the Head of Engineering. Relocation assistance and sponsorship are not available.

Requirements

At least 5 years of full-time industry software engineering experience, with a record of shipping production features and supporting them after launch.
Strong TypeScript or Python skills and comfort working across APIs, databases, and frontend development when needed.
Hands-on experience building production LLM features, including tool use, retrieval, structured output, and evaluation.
Experience with an agent framework and observability stack; LangChain, LangGraph, LangSmith, or Langfuse are preferred, or be able to demonstrate experience with alternatives and how their results were evaluated.
An agent-first approach, with experience building tooling around coding agents such as skills, MCP servers, custom workflows, or evaluations.
Ability to build within systems designed by others, make a case for disagreements, and deliver the agreed plan.
Habit of documenting work through design notes, evaluation results, and runbooks.
Enjoy working on a small team through pairing, code review, and shared ownership.
High agency in an ambiguous, fast-moving startup environment, including identifying valuable workflows to automate and shipping solutions without waiting for a perfect specification.
BS in computer science or a related field, or equivalent experience.

Nice To Haves

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.

Responsibilities

Build and ship agents and multi-agent workflows for operations, dealers, and sellers, including document extraction, inspection and title review, communications, and internal tooling.
Build agents using LangChain and LangGraph, and trace, debug, and evaluate them with LangSmith or Langfuse.
Write evaluations, build datasets from real cases, measure accuracy and failure modes, and make regressions visible.
Integrate agents with existing services through clean APIs and tools, work within the existing architecture, and raise design concerns with the owning engineer.
Monitor agents in production for cost, latency, error rates, and human-review rates; address failures and improve prompts, tools, and guardrails.
Build TypeScript and React review and correction screens and the supporting backend endpoints when needed.
Help engineering adopt shared agent-building patterns by creating reusable tools, examples, and short write-ups.