Senior Backend Engineer — AI Agents & Evaluation

Bigcommerce; United States; Remote; USD 116,000 - 195,000; Full time

Job summary

BigCommerce is building a new team to deliver a suite of conversational AI agents spanning the B2B commerce lifecycle. As a Senior Backend Engineer specializing in AI agents, you will design orchestration, sub-agent architecture, tool integration, prompt engineering, and — critically — the evaluation discipline that determines whether these agents are trustworthy enough to ship.

BigCommerce, part of Commerce, enables merchants to grow with a leading e-commerce platform.

Qualifications

• Bachelor's degree in CS/EE/SW/CE/MIS or equivalent experience.
• Hands-on experience building agentic AI/LLM apps.
• Strong API design and integration across systems.
• Experience with LLMs in production.
• Familiarity with evaluation/observability platforms.
• Proficient in Go and Python; knowledge of Go/Python/Ruby/PHP.

Responsibilities

• Design, build, and iterate on AI agents in Go/Python using an orchestrator/sub-agent architecture, covering intent interpretation, delegation, and safe action execution.
• Own eval-driven development: build and maintain golden datasets, scorers, and regression suites for critical quality metrics.
• Develop and refine prompts, model configurations; treat prompts and model settings as versioned, tested artifacts.
• Integrate agents with MCP servers and backend tools, defining safe tool‑call contracts, approval flows for write actions, and guardrails against prompt injection and abuse.
• Instrument agents with tracing, metrics, and cost tracking; use production signals to drive quality improvements.
• Collaborate with product designers and frontend engineers to deliver intuitive, useful conversational experiences.
• Quickly build proof‑of‑concept agents to validate user stories, then harden them to GA quality.
• Drive architecture decisions on ambiguous problems and mentor other engineers in agent engineering practices.

Skills

Backend development

AI/LLM applications

Go

Python

API design

LLM evaluation

Education

Bachelor's degree

Tools

MCP servers

LLM tool integrations

Google ADK

Job description

BigCommerce is building a new team to deliver a suite of conversational AI agents spanning the B2B commerce lifecycle. As a Senior Backend Engineer specializing in AI agents, you will design orchestration, sub-agent architecture, tool integration, prompt engineering, and — critically — the evaluation discipline that determines whether these agents are trustworthy enough to ship.

BigCommerce, part of Commerce, enables merchants to grow with a leading e-commerce platform.