Customiser sizes

Update a size

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Applies an RFC 7396 JSON Merge Patch to one size: properties omitted from the body are unchanged, and null clears a nullable property. Read-only and unknown fields are rejected, as is any field the customiser's pricing model does not read.

PATCH/api/v3/customisers/{customiser_id}/sizes/{size_id}

Update a size

Applies an RFC 7396 JSON Merge Patch to one size: properties omitted from the body are unchanged, and `null` clears a nullable property. Read-only and unknown fields are rejected, as is any field the customiser's pricing model does not read. An empty object `{}` is a valid no-op. Requires `customisers:write`. The patch is judged on the state it would leave behind, so clearing a dimension the pricing model prices by is refused even when the body only names that one field. An `Idempotency-Key` is optional here: sending one makes the update safe to retry (an exact repeat replays the original response; the same key with a different body is a 409). The update clears the customiser's cached storefront configuration and runs the advisory language sync, and never regenerates Shopify products, product images, or the product cache.

Authorisation

Authorizationstring<bearer>required

The Authorization header expects a Bearer token. Generate one on the API keys page in your dashboard.

Path

customiser_idintegerrequired

The customiser id.

size_idintegerrequired

The size id, from the list sizes operation.

Bodyapplication/json

Update a size

Overview

An empty object {} is a valid no-op. Requires customisers:write. The patch is judged on the state it would leave behind, so clearing a dimension the pricing model prices by is refused even when the body only names that one field. An Idempotency-Key is optional here: sending one makes the update safe to retry (an exact repeat replays the original response; the same key with a different body is a 409). The update clears the customiser's cached storefront configuration and runs the advisory language sync, and never regenerates Shopify products, product images, or the product cache.

Authorisation

Bearer token required. Include it in the Authorization header.

Required scope: customisers:write

Path parameters

customiser_idstringpathrequired

The customiser id.

Example: 1

size_idstringpathrequired

The size id.

Example: 1

Request body

namestringbody

descriptionstringbody

char_limitintegerbody

line_limitintegerbody

min_charintegerbody

width_cmintegerbody

height_cmintegerbody

line_height_cmintegerbody

length_cmintegerbody

width_multipliernumberbody

border_margin_cmnumberbody

Request body example

{
  "name": "Small",
  "description": "Fits a shop window",
  "char_limit": 12,
  "line_limit": 1,
  "min_char": 1,
  "width_cm": 40,
  "height_cm": 20,
  "line_height_cm": 10,
  "length_cm": 120,
  "width_multiplier": 1.5,
  "border_margin_cm": 5.08
}

Update a size

curl https://web.signcustomiser.com/api/v3/customisers/1/sizes/1 \
  --request PATCH \
  --header 'Accept: application/json' \
  --header 'Authorization: Bearer YOUR_API_TOKEN' \
  --header 'Content-Type: application/json' \
  --data '{
  "name": "Small",
  "description": "Fits a shop window",
  "char_limit": 12,
  "line_limit": 1,
  "min_char": 1,
  "width_cm": 40,
  "height_cm": 20,
  "line_height_cm": 10,
  "length_cm": 120,
  "width_multiplier": 1.5,
  "border_margin_cm": 5.08
}'

{
  "data": {
    "object": "size",
    "id": 7,
    "customiser_id": 42,
    "name": "Medium",
    "description": "Fits a shop window",
    "char_limit": 12,
    "line_limit": 1,
    "min_char": 1,
    "width_cm": 60,
    "height_cm": null,
    "line_height_cm": 10,
    "length_cm": null,
    "width_multiplier": null,
    "sizing_strategy": "fixed_width",
    "height_measurement_mode": "line_height",
    "border_margin_cm": 5.08,
    "sort_order": 1,
    "created_at": "2026-08-13T00:00:00Z",
    "updated_at": "2026-08-13T00:05:00Z"
  },
  "links": {
    "self": "https://web.signcustomiser.com/api/v3/customisers/42/sizes/7",
    "documentation": "https://www.signcustomiser.com/help/api/"
  },
  "meta": {
    "api_version": "v3",
    "request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
  }
}

{
  "type": "https://www.signcustomiser.com/help/api/problems/malformed_json",
  "title": "Malformed JSON",
  "status": 400,
  "code": "malformed_json",
  "detail": "The request body is not valid JSON: Syntax error.",
  "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/idempotency_key_conflict",
  "title": "Idempotency key conflict",
  "status": 409,
  "code": "idempotency_key_conflict",
  "detail": "This Idempotency-Key was already used for a different request body on this operation.",
  "request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
}

{
  "type": "https://www.signcustomiser.com/help/api/problems/request_too_large",
  "title": "Request too large",
  "status": 413,
  "code": "request_too_large",
  "detail": "The request body must not exceed 2 MiB.",
  "request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
}

{
  "type": "https://www.signcustomiser.com/help/api/problems/validation_failed",
  "title": "Validation failed",
  "status": 422,
  "code": "validation_failed",
  "detail": "The request payload failed validation.",
  "errors": [
    {
      "pointer": "/size_id",
      "code": "prohibited",
      "detail": "The size_id field is prohibited."
    }
  ],
  "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"
}