Senior Software Engineer, Agentic Commerce

ThredUp is transforming resale through technology and a mission to make secondhand shopping easier and more sustainable. The Senior Software Engineer, Agentic Commerce will design and build the end-to-end agentic-commerce layer that enables AI shopping agents to discover and transact with ThredUp products, while shaping the roadmap and delivering production-grade services.

Responsibilities:

• Design and build the agentic-commerce layer end to end — from exposing our catalog, pricing, and inventory to AI shopping agents through cart, checkout, and order handoff — defining the integration surface rather than inheriting one
• Own how ThredUp gets discovered and surfaced by LLM-driven shopping agents, including the structured data that makes 4M+ unique, single-SKU items legible to machines
• Prototype quickly against real agent platforms, then harden what proves out into production-grade services — working across the stack, wherever the problem lives
• Use AI tools and agentic workflows as a core part of how you build, setting the bar for what AI-native engineering looks like at ThredUp
• Partner with engineering, product, and executive leadership to turn an undefined space into a roadmap, carry it from idea to shipped, and let real customer usage drive what comes next
• Our stack: Ruby on Rails, Java/JVM, MySQL, Kafka, Redis, Sidekiq, OpenSearch, AWS, Kubernetes, Terraform. Apollo GraphQL API gateway. React, PWA, native iOS and Android. No prior experience with any particular piece required

Requirements:

• 5+ years of software engineering experience, owning systems end to end from ambiguous problem to production
• Fluent daily use of LLMs and agentic coding tools, with strong instincts for where AI output needs human judgment
• Experience building or deploying systems powered by LLMs, and an understanding of how model behavior shapes product experience
• Strong API and integration design skills, for interfaces consumed by other systems rather than by people
• Depth in backend engineering with the range to work across the stack. Design judgment matters more here than which languages you've used
• Genuine curiosity about a space that changes monthly — new protocols, new tooling, new model capabilities — and the habit of keeping up with it
• Comfort working from a blank page without a surrounding team to make progress
• The judgment to scope a problem, put a plan behind it, and drive it to shipped rather than exploring indefinitely
• Clear communication with engineers and non-technical executives alike
• This role is not eligible for visa sponsorship
• Familiarity with the Agentic Commerce Protocol (ACP), MCP, or other emerging agentic-commerce standards is a plus
• E-commerce or marketplace experience is a plus
• Experience having built something from zero, whether at a startup or inside a larger company is a plus