Sign Customiser

Customiser support finishes

Attach a support finish image

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Takes the raster image of a staged upload and puts it in one of the support finish's three image slots, returning the support finish with that slot's *_url pointing at the new file. Requires customisers:write and an Idempotency-Key.

PUT/api/v3/customisers/{customiser_id}/support-finishes/{support_finish_id}/images/{image_slot}

Overview

Create the upload first with POST/api/v3/uploads — purpose option_image for preview_image or example_image, option_texture_image for texture_image — send the bytes to the presigned target it returns, then send that upload's id here. An upload whose purpose is not the slot's answers 422 upload_purpose_mismatch. The upload is single use: attaching it a second time answers 409, and each slot needs its own upload. Only PNG, JPEG and WebP are accepted. SVG is refused when the upload is created, because the option-image path stores files as they arrive and does not sanitise them. The bytes are verified here, not at create: the object must exist, be within the purpose's cap, start with the magic bytes of the type it was declared as, and carry a readable image header. A file that fails leaves the upload rejected with the failure's code, and attaching it again replays that code — fix the file and create a new upload rather than retrying. Attaching to a slot that already holds an image replaces it. The previous file is deleted once the new one is committed, so any URL published for it stops resolving. Attaching to texture_image is what makes the texture finish kind available: send the image here first, then set finish_kind on the finish itself. The attach clears the customiser's cached storefront configuration and runs the advisory language sync. It never regenerates Shopify products, product images, or the product cache.

Authorisation

Bearer token required. Include it in theAuthorization header.

Required scope: customisers:write

Path parameters

customiser_idstringpathrequired

The customiser id.

Example: 1

support_finish_idstringpathrequired

The support finish id.

Example: 27

image_slotstringpathrequired

Which of the support finish's images to write (closed set): the swatch a shopper picks from, the example photograph beside it, or the texture the texture finish kind is tiled from.

Example: preview_image

Request body

upload_idstringbody

Request body example

application/json
{
  "upload_id": "upl_9f2c4b7ad13e6058ba41cd"
}
Attach a support finish image
curl https://web.signcustomiser.com/api/v3/customisers/1/support-finishes/27/images/preview_image \
  --request PUT \
  --header 'Accept: application/json' \
  --header 'Authorization: Bearer YOUR_API_TOKEN' \
  --header 'Content-Type: application/json' \
  --data '{
  "upload_id": "upl_9f2c4b7ad13e6058ba41cd"
}'
Response
{
  "data": {
    "object": "support_finish",
    "id": 27,
    "customiser_id": 42,
    "name": "Gloss Black",
    "description": null,
    "finish_kind": "colour",
    "hexcode": "#111111",
    "opacity": 1,
    "applied_to_visualisation": true,
    "backboard_ids": [
      11
    ],
    "min_width_cm": null,
    "min_height_cm": null,
    "min_size_rule": "any",
    "base_price": 0,
    "currency": "USD",
    "price_multiplier": 1,
    "price_multiplier_target": "base_letter_price",
    "sort_order": 1,
    "preview_image_url": "https://cdn.example.com/files/2f1c9c0e-6a7b-4c1d-8e2f-3a4b5c6d7e8f.png",
    "example_image_url": null,
    "texture_image_url": null,
    "created_at": "2026-08-13T00:00:00Z",
    "updated_at": "2026-08-13T00:05:00Z"
  },
  "links": {
    "self": "https://web.signcustomiser.com/api/v3/customisers/42/support-finishes/27/images/preview_image",
    "documentation": "https://www.signcustomiser.com/help/api/"
  },
  "meta": {
    "api_version": "v3",
    "request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
  }
}