Connect an AI Assistant to eBay's Official Read-Only API Tool
What it is
eBay publishes an official open-source tool called the eBay API MCP server (npm package @ebay/npm-public-api-mcp, on eBay's own GitHub). MCP is a standard way to plug an AI assistant, such as a desktop chat app or a coding editor, into outside tools. With this one connected, you can ask in plain English things like "What item specifics are required for this category?" and the assistant calls eBay's real APIs to find out.
Why it matters now
Since February 2026 eBay's User Agreement bans unapproved scrapers and LLM-driven bots. The proper route for AI projects is eBay's developer APIs, used under your own developer account. The official MCP tool is a safe way to start. As of September 2026 its readme says it only does read requests in production (GET only, with POST, PUT and DELETE unavailable) and that sandbox isn't officially supported. It can look things up but can't change your listings, which is exactly what you want for a first project.
How to try it this week
- Sign up for a free eBay Developers Program account at developer.ebay.com and create an application to get your keys. Check the current programme terms before you start.
- Start in Application Token mode, which uses only your app's Client ID and Secret and gives access to public data. Leave the user-token mode, which reaches your own orders and inventory, until you're comfortable.
- Follow the readme to add the server to an MCP-capable assistant. It runs on your own computer with Node.js.
- Project idea, the item-specifics gap check: pick a category you sell in a lot and ask the assistant to use the Taxonomy API (getItemAspectsForCategory) to list the required and recommended item specifics. Compare that list with a few of your own live listings and note what's missing.
- Second idea: use the Browse API to look at how active listings for one product are titled and priced right now. That's live listings only, not sold data.
Human-in-the-loop checkpoint
Treat everything the assistant tells you as a lead, not an answer. Check any "required aspect" claim against the listing form in Seller Hub before changing listings in bulk. And if you later move to tools that can write (edit or revise listings), work in three steps: the AI proposes the changes, you approve each one, then it applies them. Do a small dry run before any bulk run.
Cost and energy note
The developer account and the MCP tool are free. eBay APIs have daily call limits. You pay for whatever AI assistant you connect. Keep your requests narrow, one category at a time, and you'll stay well inside both.
Security notes
- Your Client Secret and any refresh token are like passwords. Keep them in the tool's config on your own machine. Never paste them into a chat, a forum post or a shared document.
- Stick to the official eBay repository. Several unofficial "eBay MCP" copies exist on GitHub. Some are genuine community projects, but they can have much wider write access. Read before you install.
- Revoke and regenerate keys if you think they've been exposed.
Pitfalls
- Marketplace Insights, the sold-data API, is limited-access, so don't plan a project around it unless eBay has approved you.
- Make sure you're querying the UK marketplace (EBAY_GB) and not the US default.
Sources: github.com/eBay/npm-public-api-mcp | developer.ebay.com/api-docs/commerce/taxonomy/resources/cat… | developer.ebay.com/api-docs/buy/browse/overview.html
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