usefulapiCustomCat MCP server
Browse the CustomCat catalog, your products and designs; check shipping; create and cancel orders. Hosted by usefulapi: connect it to Claude, ChatGPT, Cursor or any MCP client.
What can I ask?
Turn on the CustomCat connector, then ask in plain words. The AI picks the tools.
- What is the status of order 101-102938 and has it shipped?
- List the products I set up in CustomCat and their variant SKUs.
- Is catalog SKU 39515 in stock, and what would shipping to Detroit cost?
- Place a sandbox test order for two of my Red / Large shirts to Joe Testing in Detroit.
What you can do with CustomCat in Claude and ChatGPT
For print-on-demand sellers who make and ship custom products with CustomCat.
List our products, variants and designs
Lists the products you set up with variants, SKUs, cost and price, opens one product, and lists the uploaded designs.
Browse the catalog of blank products
Lists catalog categories and the blank products you can print on, and shows a product's colors, sizes and SKUs.
Check stock for a SKU and the shipping cost
Checks a catalog SKU for price and stock status, lists the shipping methods for a country, and quotes the shipping cost for SKUs and quantities.
Check an order's status and tracking
Reads an order by your order id: its status, production status of each item, shipments with tracking ids and totals.
Place an order for printing and shipping
Places an order for CustomCat to print and ship. It charges the payment method on file, so check the SKUs and shipping method first.
Changes dataCancel an order
Cancels an order by your order id. Only an order that has not gone into production can be cancelled.
Changes dataHow do I connect CustomCat?
Before you connect
The login page asks for your CustomCat API key.
Find it in the CustomCat app (customcat-beta.mylocker.net) → Settings: CustomCat creates two keys, a Read key and a Write key. Use the Read key for look-ups only; use the Write key if you want the assistant to place or cancel orders (an order charges the payment method on your CustomCat account). Your key is used only to call the CustomCat API on your behalf; it is never shown to anyone.
Claude claude.ai · Desktop
- Open Customize → Connectors, then click + Add → Add custom connector.
- Enter the name CustomCat and this URL, then click Add:https://
customcat. usefulapi. io/ mcp - Claude opens the login page: enter your CustomCat API key.
- In a chat, click + → Connectors and turn on CustomCat.
Team and Enterprise: an Owner adds the connector for the organization first.
ChatGPT chatgpt.com
- Open Plugins, click +, then Add custom MCP server.
- Enter the name CustomCat and this URL, choose OAuth as the authentication, confirm the warning and create it:https://
customcat. usefulapi. io/ mcp - ChatGPT opens the login page: enter your CustomCat API key.
- In Plugins, install CustomCat, then choose it in a chat.
No Add custom MCP server option? It depends on your account or workspace settings: see OpenAI's guide.
Claude Code
Run this command, then run /mcp in Claude Code to log in:
Cursor
Add to Cursor or add this to ~/.cursor/mcp.json:
{
"mcpServers": {
"customcat": {
"url": "https://customcat.usefulapi.io/mcp"
}
}
} VS Code
Add to VS Code or add this to .vscode/mcp.json:
{
"servers": {
"customcat": {
"type": "http",
"url": "https://customcat.usefulapi.io/mcp"
}
}
} Codex
Run these commands. The second one opens the login page:
Other clients
Windsurf, Cline, Zed and other MCP clients: add this URL as a remote MCP server (Streamable HTTP). The client then opens the login page in your browser.
Add only the URL. Do not add an Authorization header or an API key to the client config. The server signs you in with OAuth: the login page asks for your CustomCat API key. If the config has such a header, remove it: some clients then send that header instead of the login token, and every call fails with 401.
Pricing
| Plan | Price | Limit |
|---|---|---|
| Free | $0 | 50 tool calls / month |
| Proper user | $9/mo · $90/yr | 10,000 tool calls / month |
| Pro+per user | $39/mo · $390/yr | 100,000 tool calls / month |
Each paid plan covers this CustomCat server only. Ask your AI to run customcat_upgrade and choose Pro or Pro+, billed monthly or yearly (it returns a Stripe Checkout link). If you already have Pro, ask to change it to Pro+. The change requires your confirmation, keeps your billing interval and charges the price difference for the rest of the period immediately. Cancel any time with customcat_cancel_subscription: your paid plan continues to the end of the paid period, with no refund for the current period, and asking to resume the same plan with customcat_upgrade before then undoes the cancel. Or write to support@usefulapi.io.
Tools 16
Show all 16 tools (the AI picks them for you)
Read only · 10
- List your products
customcat_list_productsList the products you set up in CustomCat (a design on one or more catalog items) with variants, SKUs, cost, price, stock flag and design images. Use the variant SKUs when placing an order for these products. - Get one of your products
customcat_get_productOne of your CustomCat products by id (e.g. 22-2580581): variants, SKUs, cost, price, options, designs. - List your designs
customcat_list_designsList the designs uploaded to your CustomCat account: id, name, tags, image URLs, default product and last-updated time. - List catalog categories
customcat_list_catalog_categoriesThe CustomCat catalog categories (Digisoft, Sublimation) and their subcategories (e.g. T-Shirts, Sweatshirts, Bags), to narrow customcat_list_catalog. - List the blank-product catalog
customcat_list_catalogBrowse the full CustomCat catalog of printable blank products (the items you can order with your own artwork). Filter by category and subcategory from customcat_list_catalog_categories. The reply carries the total in `total`. - Get a catalog product
customcat_get_catalog_productOne catalog product by numeric id with its colors, sizes and SKUs. - Get a catalog SKU (stock check)
customcat_get_catalog_skuOne catalog SKU with its price and stock status. Use it before ordering: a SKU that is out of stock, discontinued or invalid makes the order fail. - List shipping methods
customcat_list_shipping_methodsThe shipping methods CustomCat offers for a destination country (ids and names). The method name is required when placing an order. - Get the shipping cost for items
customcat_get_shipping_costCalculate the shipping cost of one shipping method for a destination and a list of catalog SKUs with quantities. Read-only quote: it places nothing. POST /shipping/{shipping_id} (shipping_id from customcat_list_shipping_methods). - Get order status
customcat_get_order_statusStatus of an order by YOUR order id: order status (Pending, Verified, Shipped), per-item production status, shipments with tracking ids, totals and the ship-to address. Set sandbox=true to look up a sandbox test order.
Changes data · 2
- Place an order
customcat_create_orderWRITE: place an order for CustomCat to print and ship. This CHARGES the payment method on file in your CustomCat account (product cost + shipping; a front+back print adds $5 per line item) unless sandbox=true, which only validates the order. A real order (sandbox=false) also needs confirm=true, set only after the user confirmed it. The order id is yours and must be new (a duplicate is rejected). Needs the Write API key. Check stock with customcat_get_catalog_sku and the method name with customcat_list_shipping_methods first, and confirm the details with the user before calling. - Cancel an order
customcat_cancel_orderWRITE: cancel (delete) an order by YOUR order id. CustomCat can only cancel an order that has not gone into production; one already printed or shipped is refused. Needs the Write API key. Confirm with the user first.
Your usefulapi plan · 4
- Usage status (free-tier meter)
customcat_usage_statusReport the caller's current usage: the plan, calls used this month, the limit of the plan (the free monthly cap or the Pro fair use limit), remaining, and whether the limit is reached. Read-only; does not count against the meter. - Request a missing feature
customcat_request_featureTell usefulapi that the user needs something the CustomCat tools cannot do yet (a missing tool, field or filter). Call it only when the user asks for something none of the tools can do, and tell the user that you send the request. Do not call it for errors or for normal requests. Do not include personal data, credentials or customer records. Stored with the product name and the client type (for example Claude or Cursor), without the user's account. At most 5 requests per day. Does not count against the meter. - Upgrade to Pro or Pro+
customcat_upgradeGet a paid plan for CustomCat (the free tier caps monthly usage). Pro: 10,000 tool calls a month, for normal use — plan "monthly" ($9/month) or "yearly" ($90/year, 2 months free). Pro+: 100,000 tool calls a month, for automations and heavy use — plan "plus" ($39/month) or "plus_yearly" ($390/year). Without a plan it returns both Pro and Pro+, each with a payment link, for the user to choose; with a plan, one link. An existing Pro subscription changes to Pro+ in place: call without confirm first, as the reply states the exact charge for this account (the price difference for the rest of the period, or in a free Pro trial the full Pro+ price, as the trial ends); then call with confirm: true. Cancel any time: the plan then runs to the end of the paid period, so it also suits a one-time job. A link opens Stripe Checkout in the browser; after payment the account upgrades automatically. Does not count against the meter. - Cancel the Pro subscription
customcat_cancel_subscriptionCancel the caller's CustomCat Pro subscription at the end of the paid period (no refund for the current period; Pro continues until then, then the free tier applies). Requires confirm: true. Run customcat_upgrade later to undo the cancel before the period ends. Does not count against the meter.
FAQ
What can I do with CustomCat in Claude or ChatGPT?
List our products, variants and designs. Browse the catalog of blank products. Check stock for a SKU and the shipping cost. Check an order's status and tracking. Place an order for printing and shipping. Cancel an order. See what you can do for the details.
Is this an official CustomCat product?
No. usefulapi is an independent service. It is not affiliated with or endorsed by CustomCat. The server calls the CustomCat API with your own CustomCat access, so it sees only the data that your account can see.
Can I connect CustomCat to Claude or ChatGPT?
Yes. In Claude, add this server's URL as a custom connector. In ChatGPT, add it as a custom MCP server in Plugins. Then log in once. Cursor, VS Code, Claude Code and Codex work too. See the setup steps.
What do I need to connect?
The login page asks for your CustomCat API key. See Before you connect for where to find it.
Do I put my CustomCat key or an Authorization header in the client config?
No. Add only the URL. Do not add an Authorization header or an API key to the client config. The server signs you in with OAuth: the login page asks for your CustomCat API key. If the config has such a header, remove it: some clients then send that header instead of the login token, and every call fails with 401.
How do you keep my CustomCat credentials?
The login stores them encrypted in the authorization grant of your connection. The server uses them to call the CustomCat API for you and to derive a private account id for usage metering. usefulapi does not show them on any page or in any reply. To stop all access, remove the connector and change or delete these credentials in CustomCat.
Can the AI change my CustomCat data?
Yes, if you approve it. 2 of the 12 CustomCat tools can create or change data. The other 10 are marked read-only. Most MCP clients ask you to approve a tool call before it runs.
What does it cost?
The Free plan gives 50 tool calls / month. Pro costs $9/mo or $90/yr, with 10,000 tool calls / month. Pro+ costs $39/mo or $390/yr, with 100,000 tool calls / month. Each subscription covers this CustomCat server only. Cancel any time: your paid plan then runs to the end of the paid period. Run customcat_usage_status to see how many calls you used.
How do I subscribe or cancel?
Ask the AI to run customcat_upgrade and choose Pro or Pro+, billed monthly or yearly: it returns a Stripe Checkout link. If you already have Pro, ask to change it to Pro+. After you confirm, your existing subscription changes in place, keeps its billing interval and charges the price difference for the rest of the period immediately. To cancel, run customcat_cancel_subscription. Your paid plan continues to the end of the paid period.
What if a CustomCat tool that I need is missing?
Tell the AI what you wanted to do. It can send the request with customcat_request_feature. We store the text with the server name, the type of AI client and the tool you tried, not with your account, and read every request when we plan new tools. You can send up to 5 requests per day.
Which AI clients can I use?
Any client that supports remote MCP servers (Streamable HTTP) with OAuth login: Claude (web and desktop), Claude Code, ChatGPT, Codex, Cursor, VS Code, Windsurf and others.
This is a Model Context Protocol endpoint — meant to be connected from an AI client, not opened in a browser. An invalid_token response at the URL is the auth gate working as designed; clients authenticate automatically.
Need a tool this server does not have, or a connection to another system? We build custom integrations and MCP servers.