# PATCH Update a letter part's colour

Applies an RFC 7396 JSON Merge Patch to one of this letter part's colours. The semantics are the customiser colours family's, unchanged: omitted properties are unchanged, `null` clears a nullable property, arrays are replaced wholesale, read-only and unknown fields are rejected, and the patched result must still be renderable. Requires `customisers:write`. An `Idempotency-Key` is optional here: sending one makes the update safe to retry. 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.

- Source URL: https://www.signcustomiser.com/help/api/v3-patch-update-a-letter-part-s-colour/
- Markdown URL: https://www.signcustomiser.com/help/api/v3-patch-update-a-letter-part-s-colour.md
- Group: Customiser letter parts
- Method: PATCH
- Path: /api/v3/customisers/{customiser_id}/letter-types/{letter_type_id}/letter-parts/{letter_part}/colours/{colour_id}
- Auth: Bearer token
- Required scopes: `customisers:write`

## Path parameters

- customiser_id (string, required): The customiser id. Example: 1
- letter_type_id (string, required): The letter type id. Example: 7
- letter_part (string, required): The letter part. Example: face
- colour_id (string, required): The colour id. Example: 31

## Body parameters

- colour_type (string, optional): No description provided.
- texture (string, optional): No description provided.
- min_size_rule (string, optional): No description provided.
- price_multiplier_target (string, optional): No description provided.
- name (string, optional): No description provided.
- description (string, optional): No description provided.
- hexcode (string, optional): No description provided.
- multi_colour_hexcodes (array, optional): No description provided.
- base_price (integer, optional): No description provided.
- price_multiplier (number, optional): No description provided.

## Request body example

```json
{
  "colour_type": "single",
  "texture": "flat",
  "min_size_rule": "any",
  "price_multiplier_target": "base_letter_price",
  "name": "Warm White",
  "description": "Our warmest white",
  "hexcode": "#FFEEDD",
  "multi_colour_hexcodes": [
    "#FF0000",
    "#00FF00"
  ],
  "base_price": 500,
  "price_multiplier": 1.2
}
```

## cURL example

```bash
curl https://web.signcustomiser.com/api/v3/customisers/1/letter-types/7/letter-parts/face/colours/31 \
  --request PATCH \
  --header 'Accept: application/json' \
  --header 'Authorization: Bearer YOUR_API_TOKEN' \
  --header 'Content-Type: application/json' \
  --data '{
  "colour_type": "single",
  "texture": "flat",
  "min_size_rule": "any",
  "price_multiplier_target": "base_letter_price",
  "name": "Warm White",
  "description": "Our warmest white",
  "hexcode": "#FFEEDD",
  "multi_colour_hexcodes": [
    "#FF0000",
    "#00FF00"
  ],
  "base_price": 500,
  "price_multiplier": 1.2
}'
```

## Response examples

### 200 PATCH 200 example 1

```json
{
  "data": {
    "object": "colour",
    "id": 31,
    "customiser_id": 42,
    "name": "Warm White",
    "description": "Our warmest white",
    "colour_type": "single",
    "hexcode": "#FFEEDD",
    "multi_colour_hexcodes": null,
    "texture": "flat",
    "min_width_cm": null,
    "min_height_cm": null,
    "min_size_rule": "any",
    "base_price": 500,
    "currency": "USD",
    "price_multiplier": 1,
    "price_multiplier_target": "base_letter_price",
    "sort_order": 1,
    "image_url": null,
    "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/letter-types/7/letter-parts/face/colours/31",
    "documentation": "https://www.signcustomiser.com/help/api/"
  },
  "meta": {
    "api_version": "v3",
    "request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
  }
}
```

### 400 Malformed JSON body

```json
{
  "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"
}
```

### 401 Missing API key

```json
{
  "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"
}
```

### 403 Insufficient scope

```json
{
  "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"
}
```

### 404 Unknown colour

```json
{
  "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"
}
```

### 409 Idempotency conflict

```json
{
  "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"
}
```

### 413 Request body too large

```json
{
  "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"
}
```

### 422 Read-only field

```json
{
  "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": "/sort_order",
      "code": "prohibited",
      "detail": "The sort order field is prohibited."
    }
  ],
  "request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
}
```

### 429 Option write budget exhausted

```json
{
  "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"
}
```