Senior Backend Engineer (AI Agent)
About The Position
BigCommerce is building a team of conversational AI agents for the B2B commerce lifecycle, including product discovery, pricing and quoting, order automation, fulfillment and delivery, and post-sale support. The agents use Go, Google ADK, Gemini, Braintrust evaluation infrastructure, and a streaming AG-UI frontend. The Senior Backend Engineer will design and build the agents, including orchestration, sub-agent architecture, tool integrations, prompt engineering, and evaluation practices that establish whether agents are reliable enough to ship. The role includes building proof-of-concept agents, hardening them to general-availability quality, and driving architecture decisions on ambiguous problems. The position collaborates with product designers and frontend engineers and mentors other engineers in agent engineering practices. Commerce is a remote-first company. Team members in Austin, Atlanta, and London may use optional collaborative workspaces for team gatherings, workshops, and in-person connection. Compensation is a national base salary range of $116,000 to $195,000; final pay depends on relevant experience, skills, qualifications, geographic location, and internal equity. The role may also be eligible for variable compensation, equity, and benefits according to local policies.
Requirements
- At least 5 years of backend or full-stack software development experience, including hands-on experience building agentic AI or LLM applications.
- Preferred minimum of a bachelor's degree in computer science, electrical engineering, software engineering, computer engineering, or management information systems, or equivalent experience.
- Strong, proven development skills in a major programming language such as Go, Python, Ruby, or PHP.
- Experience working with LLMs such as Gemini, Anthropic, or OpenAI in production systems.
- Experience with LLM evaluation, including building datasets, defining scorers or metrics, and using evaluation results to drive iteration.
- Strong understanding of prompt engineering, tool or function calling, and agent orchestration patterns.
- Deep experience designing and building APIs (gRPC, GraphQL, or 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 for execution and delivery.
Nice To Haves
- Experience with agent frameworks such as Google ADK, LangChain/LangGraph, or Semantic Kernel.
- Experience with evaluation or observability platforms such as Braintrust or LangSmith.
- 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 or Python using orchestrator and sub-agent architecture, including intent interpretation, delegation, and safe action execution.
- Own evaluation-driven development by building and maintaining golden datasets, scorers, and regression suites for critical quality metrics such as discovery recall and quote accuracy.
- Develop and refine prompts and model configurations, treating them as versioned and 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, and use production signals to drive quality improvements.
- Collaborate with product designers and frontend engineers to deliver useful conversational experiences.
- Build proof-of-concept agents to validate user stories and harden them to general-availability quality.
- Drive architecture decisions on ambiguous problems and mentor other engineers in agent engineering practices.
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What This Job Offers
Job Type
Full-time
Career Level
Senior
