Turn McMaster-Carr into an API

What you can build on McMaster-Carr

• Get prices for part numbers

  Build this

  Opens each part number's product page and reads its price by quantity and unit, its status and its description.

  Takes

  Part numbers

  Returns

  Part number, description, product status, price, minimum quantity, unit, suggested replacement

• Get Order History

  Build this

  Reads Order History in your account: each order's date, status and tracking information once it ships.

  Takes

  Ordered since (optional)

  Returns

  Order number, order date, status, tracking number, carrier, total

• Get an order's invoice

  Build this

  Opens one order in Order History and reads its invoice, with the lines, amounts and whether a material certificate is available.

  Takes

  Order number

  Returns

  Invoice number, invoice date, part numbers, quantities, prices, shipping, total, certificate available

• Place an order

  Build this

  Adds part numbers with quantities to the order, enters your PO number and checks out with the payment saved on your account.

  Takes

  Part numbers with quantities, PO number, ship-to address

  Returns

  Order number, lines, estimated delivery, total

Automate McMaster-Carr with a workflow

A workflow runs your methods as one process, with nobody at the screen. A schedule or a call from your own system starts it, the steps run in order, and the result arrives in your inbox or in the systems you already use.

• Price changes on your part list

  Build this

  Starts

  Every Monday at 7:00

  Step 1

  Get prices for every part number on your list.

  Step 2

  Keep the parts whose price tiers changed since the last run.

  Step 3

  Email you each one with its old and new price and unit.

• Discontinued parts, with the suggested replacement

  Build this

  Starts

  On the 1st of every month at 8:00

  Step 1

  Get the product status of every part number on your list.

  Step 2

  Keep the parts that became inactive since the last run.

  Step 3

  Post each one, with its suggested replacement and the differences, to your ERP or Slack webhook.

• Shipped orders and invoices, sent to your accounting system

  Build this

  Starts

  Every weekday at 18:00

  Step 1

  Get Order History for the last seven days.

  Step 2

  Keep the orders that shipped since the last run, and stop when there are none.

  Step 3

  Get each order's invoice and post its lines and total to your webhook.

You can run a workflow by hand on every plan, Free included. Schedules and webhook triggers come with the paid plans, from $29 a month.

Once built, one call from your code

Once you have built a method, it is one POST to /v1/runs from your backend, or a tool an AI agent calls over MCP. This is what “Get prices for part numbers” would look like.

curl https://api.fous.com/v1/runs \
  -H "Authorization: Bearer $FOUS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "method": "www.mcmaster.com/get_part_prices",
    "input": {
      "part_numbers": [
        "4012A118",
        "7731K204"
      ]
    }
  }'

{
  "status": "completed",
  "data": {
    "parts": [
      {
        "part_number": "4012A118",
        "description": "Hex head screw, 18-8 stainless steel, 1/4\"-20 thread, 3/4\" long",
        "product_status": "Active",
        "prices": [
          {
            "amount": 11.42,
            "minimum_quantity": 1,
            "unit": "Pack of 50"
          }
        ],
        "suggested_replacement": null
      }
    ],
    "currency": "USD"
  }
}

An example with invented data, not a ready-made endpoint. The method exists in your organization once you build it, and its name, inputs and fields follow your request.

McMaster-Carr’s own options

McMaster-Carr offers a Product Information API to approved customers: it reads product details, prices, images, CAD files and datasheets, and it has no way to place or track orders. Orders can be exchanged by cXML or EDI and placed through punchout from a purchasing system, both set up with its eProcurement team.

Read on November 12, 2026: McMaster-Carr Product Information API, Automated document transmission, Punchout and eProcurement.

Signing in to McMaster-Carr

McMaster-Carr signs you in with the email address and password of your login, and the same login opens Order History and its documents. With Fous you sign in once through McMaster-Carr's own sign-in with your own account: the login is sealed with AES-256, never returned by the API, and an expired session is signed back in.

Worth knowing

The API reads products, not orders

McMaster-Carr's API has endpoints for product information, prices, CAD files and subscriptions. It has none for placing or tracking orders, so order status, invoices and certificates stay in Order History.

Certificates appear when the order ships

Material certificates come free with over 48,000 metal products. They are emailed and can be downloaded from Order History as soon as the order ships, and the one with the traceable lot number usually starts after the first page.

API tokens last 24 hours

Each approved customer gets a client certificate that must be attached to every request. A token from Log In expires after 24 hours or at Log Out, and product subscriptions have a total and a daily limit.

Card payments get no early-payment discount

Open accounts, where McMaster-Carr approves them, are net 30 with 2% off when paid within 10 days of shipment by EFT or check. The discount does not apply to payments by credit card.

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