# PUT Attach a backboard shape

Takes the SVG of a staged upload and makes it this backboard's shape, returning the backboard with `geometry.has_custom_shape` true and `geometry.status` `pending`. Requires `customisers:write` and an `Idempotency-Key`. Create the upload first with `POST /api/v3/uploads` using purpose `backboard_shape_svg`, send the bytes to the presigned target it returns, then send that upload's id here. The upload is single use: attaching it a second time answers 409, and a replacement shape needs a new upload. A shape is the one uploaded file this API stores inside its own resource rather than as a file. It is sanitised and written into the backboard, is never published as a URL, and the staged object is deleted rather than kept. `geometry` is how you read it back. The bytes are verified here, not at create: the object must exist, be within the purpose's cap, be well-formed XML with an `svg` element, carry no script elements, event-handler attributes or `javascript:` references, and still draw something once sanitised. A file that fails answers `invalid_svg` and leaves the upload `rejected`, and attaching it again replays that code — so fix the file and create a new upload rather than retrying. Attaching a shape queues server-side geometry measurement, which is why the response reports `geometry.status` `pending`. Poll the backboard until it reaches `ready`; `failed` carries a `geometry.failure_reason`. A backboard that has measured is what `backboard_type` `custom_shape` and `cutout` need, so this is the call that makes those types usable: attach the shape, then set the type in the ordinary backboard write. Sending this to a backboard that already has a shape replaces it and discards the previous measurement. Re-attaching a document that sanitises to the shape already measured is the one exception: there is nothing new to measure, so the existing `ready` result stands and the response says so rather than reporting `pending`. 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.

- Source URL: https://www.signcustomiser.com/help/api/v3-put-attach-a-backboard-shape/
- Markdown URL: https://www.signcustomiser.com/help/api/v3-put-attach-a-backboard-shape.md
- Group: Customiser backboards
- Method: PUT
- Path: /api/v3/customisers/{customiser_id}/backboards/{backboard_id}/shape
- 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 \
  --request PUT \
  --header 'Accept: application/json' \
  --header 'Authorization: Bearer YOUR_API_TOKEN' \
  --header 'Content-Type: application/json' \
  --data '{
  "upload_id": "upl_9f2c4b7ad13e6058ba41cd"
}'
```

## Response examples

### 200 PUT 200 example 1

```json
{
  "data": {
    "object": "backboard",
    "id": 11,
    "customiser_id": 42,
    "name": "Cloud Panel",
    "description": null,
    "backboard_type": "board",
    "letter_type_ids": [],
    "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": null,
    "button_image_url": null,
    "geometry": {
      "has_custom_shape": true,
      "status": "pending",
      "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/shape",
    "documentation": "https://www.signcustomiser.com/help/api/"
  },
  "meta": {
    "api_version": "v3",
    "request_id": "req_01jz9x2k7c8f3m5n6p7q8r9s0t"
  }
}
```

### 400 Missing idempotency key

```json
{
  "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"
}
```

### 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"
}
```

### 409 Upload already attached

```json
{
  "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"
}
```

### 422 Unusable SVG

```json
{
  "type": "https://www.signcustomiser.com/help/api/problems/invalid_svg",
  "title": "Invalid SVG",
  "status": 422,
  "code": "invalid_svg",
  "detail": "The shape must not contain script elements for security reasons.",
  "errors": [
    {
      "pointer": "/upload_id",
      "code": "invalid_svg",
      "detail": "The shape must not contain script elements for security reasons."
    }
  ],
  "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"
}
```