# POST Validate a backboard shape attach

Dry-runs the attach: the upload must exist for this store and this API key, and its purpose must be `backboard_shape_svg`. Nothing is written, the upload is not consumed, and no idempotency key is spent. Requires `customisers:write`. The staged bytes are deliberately not read, so this cannot tell you whether the SVG is usable — that verdict only exists once the attach reads the object, and reading it here would let a preflight mark a good upload rejected. Treat a valid verdict as "the upload is attachable", not "the shape is sound".

- Source URL: https://www.signcustomiser.com/help/api/v3-post-validate-a-backboard-shape-attach/
- Markdown URL: https://www.signcustomiser.com/help/api/v3-post-validate-a-backboard-shape-attach.md
- Group: Customiser backboards
- Method: POST
- Path: /api/v3/customisers/{customiser_id}/backboards/{backboard_id}/shape/validate-update
- Auth: Bearer token
- Required scopes: `customisers:write`

## Path parameters

- customiser_id (string, required): The customiser id. Example: 1
- backboard_id (string, required): The backboard id. Example: 11

## Body parameters

- upload_id (string, optional): No description provided.

## Request body example

```json
{
  "upload_id": "upl_9f2c4b7ad13e6058ba41cd"
}
```

## cURL example

```bash
curl https://web.signcustomiser.com/api/v3/customisers/1/backboards/11/shape/validate-update \
  --request POST \
  --header 'Accept: application/json' \
  --header 'Authorization: Bearer YOUR_API_TOKEN' \
  --header 'Content-Type: application/json' \
  --data '{
  "upload_id": "upl_9f2c4b7ad13e6058ba41cd"
}'
```

## Response examples

### 200 POST 200 example 1

```json
{
  "data": {
    "object": "backboard_shape_validation",
    "operation": "update",
    "customiser_id": 42,
    "backboard_id": 11,
    "valid": true
  },
  "links": {
    "self": "https://web.signcustomiser.com/api/v3/customisers/42/backboards/11/shape/validate-update",
    "documentation": "https://www.signcustomiser.com/help/api/"
  },
  "meta": {
    "api_version": "v3",
    "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 backboard or upload

```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"
}
```

### 422 Purpose mismatch

```json
{
  "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 backboard_shape_svg, and this upload was created with purpose option_image. Create a new upload with the slot's purpose.",
  "errors": [
    {
      "pointer": "/upload_id",
      "code": "upload_purpose_mismatch",
      "detail": "The upload's purpose is option_image.",
      "allowed_values": [
        "backboard_shape_svg"
      ]
    }
  ],
  "request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
}
```

### 429 Rate limited

```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": 60,
  "request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
}
```