Upload Customizable File

A file-type customizable option (e.g. "upload your design") needs a binary file. A file cannot travel over GraphQL, so the upload itself is a REST call — but the rest of the flow stays in GraphQL. You upload once over REST to get a token, then reference the token in the GraphQL Add to Cart mutation.

The flow

1. Read the option from the product's customizableOptions (Single Product) — a file-type option carries its _id and the allowed extensions.
2. Upload the file over REST — POST /api/shop/customizable-option-files (multipart) with product_id, option_id, file. It returns a short-lived token. This is REST-only; see the REST upload endpoint for the full request/response.
3. Add to cart over GraphQL — pass the token as that option's value: customizableOptions: { "11": ["<token>"] }. The mutation carries only the token string.
4. Core owns the rest — the file is stored with the cart, then moved to the order automatically at place-order.

Which file formats are allowed?

There is no fixed API list — the admin sets the allowed extensions per option (the option's "Supported File Extensions", e.g. pdf or jpg,png,pdf). Read them from the product's customizableOptions; a mismatched extension is rejected at upload.

Related

• Add to Cart — reference the token here
• Single Product — read the customizable options
• REST upload endpoint — the actual multipart upload