CommerceBridge

A remote MCP server that wraps the live Commerce API — eBay, Shopify, Best Buy, and Etsy marketplace data behind one /v1 contract — as MCP tools any agent (Claude, ChatGPT, etc.) can call directly.

Live: https://commercebridge-isaiahduprees-projects.vercel.app/mcp (Vercel project commercebridge, team isaiahduprees-projects) — 14 tools, verified against real production data (Shopify live; eBay/Best Buy/Etsy honestly gated until their upstream app keys are provisioned). Naming note: the clean commercebridge.vercel.app alias is owned by an unrelated third-party product (a WhatsApp-commerce chatbot) — use the team-scoped URL above, same situation as commerce-api's alias collision.

CommerceBridge does no scraping and holds no data of its own: every tool is a thin, faithful fetch relay to the upstream Commerce API. Whatever that API returns comes back unmodified, including its errors.

Why Authentication: None

This connector's underlying data — eBay/Shopify/Best Buy/Etsy marketplace listings — is fully public and carries zero per-user state. There is no account to log into, nothing to authorize, and nothing to bill per-seat. So, deliberately, CommerceBridge has:

• No OAuth — no login flow, no token exchange, no /.well-known/oauth-* endpoints

• No Supabase — no user table, no session storage

• No billing — no plans, no usage metering, no upgrade gate

This is the same architectural call this org made for StoreBridge, its sibling connector over App Store/Google Play data: public read-only marketplace data gets the lean, stateless build. It is deliberately leaner than this org's OAuth-based Bridge-family connectors (RemindersBridge, MessagesBridge, etc.), which proxy a signed-in user's own private data and do need auth.

Related MCP server: SellerChamp MCP Server

Tools

14 tools, one per Commerce API endpoint, grouped by marketplace/engine:

eBay — needs EBAY_CLIENT_ID / EBAY_CLIENT_SECRET on the upstream deployment

Shopify — keyless, live right now

Best Buy — not yet live upstream (route pending redeploy, then needs BESTBUY_API_KEY)

Etsy — not yet live upstream (route pending redeploy, then needs ETSY_KEYSTRING + ETSY_SHARED_SECRET)

Every tool is annotated {readOnlyHint:true, destructiveHint:false, idempotentHint:true, openWorldHint:true} — read-only, non-destructive, idempotent, over an open/external data source.

Expected upstream errors — not a bug

Only Shopify is live today. Every other engine's tool call returns an MCP tool error (isError: true) whose text is the upstream's honest error envelope, verbatim — but the exact error differs by engine, because the upstream commerce-api production deployment currently lags its own source repo:

• eBay (search_ebay*, get_ebay*) — the route is deployed, but app keys aren't provisioned, so you get:

  credentials_required: eBay app credentials required — set EBAY_CLIENT_ID and EBAY_CLIENT_SECRET (free at developer.ebay.com). This API wraps eBay's free Browse API.

  search_ebay_sold additionally always returns a 501 not_enabled gate regardless of eBay keys — that endpoint needs eBay's separately-approved Marketplace Insights API, which the base Browse API keys don't grant.

• Best Buy (search_bestbuy, get_bestbuy_product) and Etsy (search_etsy*, get_etsy*) — as of this writing, the code for these engines exists in the commerce-api source repo but the live production deployment has not been redeployed to include it yet, so these routes 404 at the HTTP layer, verified live:

  not_found: No route for GET /v1/bestbuy/search
  not_found: No route for GET /v1/etsy/shop

  Once commerce-api is redeployed, these will flip to credentials_required (BESTBUY_API_KEY / ETSY_KEYSTRING+ETSY_SHARED_SECRET missing) until those keys are provisioned, then to live data — with zero changes needed here.

CommerceBridge deliberately does not catch, hide, or fake around any of this — the tool handler passes whatever the upstream says straight through as {isError: true, content: [{type:'text', text: '<code>: <message>'}]}, whether that's not_found, credentials_required, or eventually real data.

Configuration

No other configuration. No secrets belong in this repo — API keys live only on the upstream commerce-api deployment.

Run locally

npm install
npm test              # local smoke test — initialize, tools/list, 2x tools/call (see below)

Deploy

npx vercel --yes --prod

That's it — no environment variables are required for CommerceBridge itself (only the upstream commerce-api deployment needs its marketplace app keys). After deploy, point any MCP client at:

https://<your-deployment>.vercel.app/api/mcp

Local smoke test

npm test runs test/smoke.mjs, which connects a real MCP Client to buildServer() from lib/tools.js over an in-memory transport (the exact same server code api/mcp.js serves over HTTP) and checks:

1. initialize — server identifies itself as commercebridge v1.0.0

2. tools/list — all 14 tools present, each with an object inputSchema and the expected RO annotations

3. tools/call → search_shopify_products (store: "allbirds.com") — asserts isError is false and real products come back with marketplace: "shopify" — proves live data flows end-to-end

4. tools/call → search_ebay — asserts isError is true and the error text contains credentials_required — proves the upstream honest gate surfaces as a clean MCP tool error, not a crash

test/local-server.mjs is a second, thinner check that runs the actual api/mcp.js / api/health.js handlers behind a plain http.Server, to confirm the Vercel-shaped handlers themselves (GET/DELETE → 405, /api/health → {ok, service, upstream}) work outside of the SDK's in-memory transport.

Architecture

lib/tools.js   — buildServer(): McpServer + all 14 tool registrations + upstream fetch relay
api/mcp.js     — POST /api/mcp — stateless StreamableHTTPServerTransport, no auth
api/health.js  — GET /api/health — {ok, service, upstream}
test/          — smoke.mjs (in-memory client/server), local-server.mjs (HTTP handler check)