Senior Backend Engineer (AI Agent)

Commerce•Atlanta, GA

1d•$116,000 - $195,000•Hybrid

About The Position

BigCommerce is building a new team to deliver a suite of conversational AI agents spanning the B2B commerce lifecycle — Product Discovery, Pricing & Quoting, Order Automation, Fulfillment & Delivery, and Post-Sale Support. The agents are built in Go on Google ADK with Gemini, with evaluation infrastructure in Braintrust and a streaming AG-UI frontend. As a Senior Backend Engineer specializing in AI agents, you will design the agents themselves: orchestration, sub-agent architecture, tool integration, prompt engineering, and — critically — the evaluation discipline that determines whether these agents are trustworthy enough to ship. Agent quality in this domain is won on evals, not just code, and you will own that practice for the team. BigCommerce, part of the Commerce brand family, helps merchants increase sales at every stage of their growth. From small startups to mid-market businesses and large enterprises, we provide the leading e-commerce platform. Our customers can then concentrate on what's most important: growing their businesses. We enable our customers to build, innovate, and grow, collectively reshaping the e-commerce industry.

Requirements

5+ years of experience in backend or full-stack software development, with hands-on experience building agentic AI/LLM applications
Strong and proven development skills in any major language (Go/Python/Ruby/PHP)
Experience working with LLMs (Gemini, Anthropic, OpenAI, etc.) in production systems
Experience with LLM evaluation: building datasets, defining scorers/metrics, and using eval results to drive iteration
Strong understanding of prompt engineering, tool/function calling, and agent orchestration patterns
Deep experience designing and building APIs (gRPC, GraphQL, REST) and integrating data across systems
Hands-on experience building MCP servers or LLM tool integrations
Excellent problem-solving skills and ability to work in a fast-paced, exploratory environment
Strong collaboration and communication skills in cross-functional teams
Strong preference toward execution and delivery

Nice To Haves

Experience with agent frameworks (Google ADK, LangChain/LangGraph, Semantic Kernel, or similar)
Experience with evaluation/observability platforms (Braintrust, LangSmith, or similar)
Experience with RAG systems and retrieval quality tuning
Experience with e-commerce platforms or SaaS product development
Background in conversational AI or natural language processing

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 (Braintrust or similar) for critical quality metrics such as discovery recall and quote accuracy
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

Benefits

Compensation Transparency
Details will be shared during the hiring process
We are committed to equitable and transparent pay practices that align to market data, internal equity, and individual contribution.
Where applicable, this role may also be eligible for variable compensation (such as bonus or commission), equity, and benefits in accordance with local policies.
Inclusion and Belonging
We are committed to creating an inclusive and accessible hiring experience for all candidates. If you require accommodations or adjustments at any stage of the recruitment process, please let us know and we will work with you to meet your needs.
Learn more about the Commerce team, culture and benefits at https://www.commerce.com/careers/
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