Senior Backend Engineer (AI Agent)

Senior Backend Engineer Specializing in AI AgentsBigCommerce 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.What You'll DoDesign, build, and iterate on AI agents in Go/Python using an orchestrator/sub-agent architecture, covering intent interpretation, delegation, and safe action executionOwn 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 accuracyDevelop and refine prompts, model configurations; treat prompts and model settings as versioned, tested artifactsIntegrate agents with MCP servers and backend tools, defining safe tool-call contracts, approval flows for write actions, and guardrails against prompt injection and abuseInstrument agents with tracing, metrics, and cost tracking; use production signals to drive quality improvementsCollaborate with product designers and frontend engineers to deliver intuitive, useful conversational experiencesQuickly build proof-of-concept agents to validate user stories, then harden them to GA qualityDrive architecture decisions on ambiguous problems and mentor other engineers in agent engineering practicesWho Are You5+ years of experience in backend or full-stack software development, with hands-on experience building agentic AI/LLM applicationsEducation: Preferred minimum Bachelor's degree in CS, EE, SW, CE, MIS; or equivalent experienceStrong and proven development skills in any major language (Go/Python/Ruby/PHP)Experience working with LLMs (Gemini, Anthropic, OpenAI, etc.) in production systemsExperience with LLM evaluation: building datasets, defining scorers/metrics, and using eval results to drive iterationStrong understanding of prompt engineering, tool/function calling, and agent orchestration patternsDeep experience designing and building APIs (gRPC, GraphQL, REST) and integrating data across systemsHands-on experience building MCP servers or LLM tool integrationsExcellent problem-solving skills and ability to work in a fast-paced, exploratory environmentStrong collaboration and communication skills in cross-functional teamsStrong preference toward execution and deliveryPreferred: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 tuningExperience with e-commerce platforms or SaaS product developmentBackground in conversational AI or natural language processingFor candidates based in the Austin or Atlanta metro area, the position follows a hybrid work model with three days per week in the office, balancing focused individual work with meaningful in-person collaboration.(Pay Transparency Range: $116,000.00 - $195,000.00)Final compensation will be determined based on factors such as relevant experience, skills, qualifications and geographic location. We also consider internal equity to help ensure fair and consistent pay practices across our teams.Where applicable, this role may also be eligible for variable compensation (such as bonus or commission), equity, and benefits in accordance with local policies. 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.At Commerce, we believe that celebrating the unique histories, perspectives and abilities of every employee makes a difference for our company, our customers and our community. We are an equal opportunity employer and the inclusive atmosphere we build together will make room for every person to contribute, grow and thrive.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.Commerce, along with many other employers, has become the subject of fraudulent job offers to hopeful prospective job seekers. Be advised: Commerce does not offer jobs to individuals who do not go through our formal hiring process. Commerce will never:require payment of recruitment fees from candidates;request personally identifiable information through unsanctioned websites or applications;attempt to solicit money from you as part of the hiring process or as part of an employment offer;solicit money to complete visa requirements as part of a job offer.If you receive unsolicited offers of employment from Commerce, we urge you to be extremely cautious and avoid engaging or responding.