Customiser backboards
Attach a backboard image
Takes the raster image of a staged upload and puts it in one of the
backboard's two image slots, returning the backboard with that slot's
*_url pointing at the new file. Requires customisers:write and an
Idempotency-Key.
Overview
Create the upload first with POST/api/v3/uploads — purpose
option_image for every slot — 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.
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
The customiser id.
Example: 1
The backboard id.
Example: 11
Which of the backboard's images to write (closed set): the artwork shown for the panel, or the smaller picture on the button that selects it.
Example: image
Request body
Request body example
{
"upload_id": "upl_9f2c4b7ad13e6058ba41cd"
}curl https://web.signcustomiser.com/api/v3/customisers/1/backboards/11/images/image \
--request PUT \
--header 'Accept: application/json' \
--header 'Authorization: Bearer YOUR_API_TOKEN' \
--header 'Content-Type: application/json' \
--data '{
"upload_id": "upl_9f2c4b7ad13e6058ba41cd"
}'{
"data": {
"object": "backboard",
"id": 11,
"customiser_id": 42,
"name": "Clear Acrylic Panel",
"description": null,
"backboard_type": "board",
"letter_type_ids": [
3
],
"outline_size": null,
"allow_multilayer": false,
"custom_background_enabled": false,
"show_custom_background": false,
"base_price": 0,
"currency": "USD",
"price_multiplier": 1,
"price_multiplier_target": "base_letter_price",
"price_per_sq_cm": null,
"sort_order": 1,
"image_url": "https://cdn.example.com/files/2f1c9c0e-6a7b-4c1d-8e2f-3a4b5c6d7e8f.png",
"button_image_url": null,
"geometry": {
"has_custom_shape": false,
"status": null,
"failure_reason": null,
"measured_at": 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/backboards/11/images/image",
"documentation": "https://www.signcustomiser.com/help/api/"
},
"meta": {
"api_version": "v3",
"request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
}
}{
"type": "https://www.signcustomiser.com/help/api/problems/missing_idempotency_key",
"title": "Missing idempotency key",
"status": 400,
"code": "missing_idempotency_key",
"detail": "Provide an Idempotency-Key header for this write.",
"request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
}{
"type": "https://www.signcustomiser.com/help/api/problems/missing_api_key",
"title": "Missing API key",
"status": 401,
"code": "missing_api_key",
"detail": "Provide a store API key as a bearer token.",
"request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
}{
"type": "https://www.signcustomiser.com/help/api/problems/insufficient_scope",
"title": "Insufficient scope",
"status": 403,
"code": "insufficient_scope",
"detail": "This operation requires the customisers:write scope.",
"required_scopes": [
"customisers:write"
],
"granted_scopes": [
"customisers:read"
],
"request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
}{
"type": "https://www.signcustomiser.com/help/api/problems/resource_not_found",
"title": "Resource not found",
"status": 404,
"code": "resource_not_found",
"detail": "The requested resource does not exist or does not belong to the authenticated store.",
"request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
}{
"type": "https://www.signcustomiser.com/help/api/problems/upload_already_attached",
"title": "Upload already attached",
"status": 409,
"code": "upload_already_attached",
"detail": "This upload has already been attached to a file slot. Each upload is single use: create a new upload for each assignment.",
"request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
}{
"type": "https://www.signcustomiser.com/help/api/problems/upload_purpose_mismatch",
"title": "Upload purpose mismatch",
"status": 422,
"code": "upload_purpose_mismatch",
"detail": "This slot accepts uploads created with purpose option_image, and this upload was created with purpose font_ttf. Create a new upload with the slot's purpose.",
"errors": [
{
"pointer": "/upload_id",
"code": "upload_purpose_mismatch",
"detail": "The upload's purpose is font_ttf.",
"allowed_values": [
"option_image"
]
}
],
"request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
}{
"type": "https://www.signcustomiser.com/help/api/problems/rate_limited",
"title": "Too many requests",
"status": 429,
"code": "rate_limited",
"detail": "You have exceeded the request limit for this API key.",
"retry_after": 37,
"request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
}