Senior Software Engineer, Agentic Commerce

**About ThredUp** ThredUp is transforming resale with technology and a mission to inspire the world to think secondhand first. By making it easy to buy and sell secondhand, ThredUp has become one of the world's largest online resale platforms for apparel, shoes and accessories. Sellers love ThredUp because we make it easy to clean out their closets and unlock value for themselves or for the charity of their choice while doing good for the planet. Buyers love shopping value, premium and luxury brands all in one place, at up to 90% off estimated retail price. Our proprietary operating platform is the foundation for our managed marketplace and consists of distributed processing infrastructure, proprietary software and systems and data science expertise. With ThredUp's Resale-as-a-Service, some of the world's leading brands and retailers are leveraging our platform to deliver customizable, scalable resale experiences to their customers. ThredUp has processed over 172 million unique secondhand items from 55,000 brands across 100 categories. By extending the life cycle of clothing, ThredUp is changing the way consumers shop and ushering in a more sustainable future for the fashion industry. Recognized on TIME Most Influential Companies of 2023,  Digiday's WorkLife 50 2023, TIME's Best Inventions of 2022, and Lattice's People Success Awards 2022. **How You Will Make An Impact** A generation of shoppers is starting to find what they want by asking an AI agent instead of browsing a website. The marketplaces those agents can read, understand, and buy from will win that traffic; the ones they can't won't get surfaced at all. As our first Senior Software Engineer for Agentic Commerce, you'll build the layer that makes 4 million unique secondhand items discoverable and transactable by AI shopping agents, and own how ThredUp shows up when someone asks an agent to find them a dress for a wedding. This is early, open territory. The standards are young, customer behaviors are still forming, and there's no established playbook to follow. You'll partner closely with engineering and product leadership to give the space shape — working out what's worth building, making the architectural decisions together, and getting real functionality in front of customers to learn from. For the first stretch you'll be the primary engineer on this work, with broad ownership of how it comes together. You'll report to our Senior Director of Engineering. **In This Role You'll Get To:** - 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. **What We're Looking For:** - 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. - 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. Many ThredUp employees also have the opportunity