# PUT Attach a font file

Takes the TrueType file of a staged upload and makes it this font's typeface, returning the font with `font_file.has_font_file` true and a live `ttf_url`. Requires `customisers:write` and an `Idempotency-Key`. Create the upload first with `POST /api/v3/uploads` using purpose `font_ttf`, 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 typeface needs a new upload. The bytes are verified here, not at create: the object must exist, be within the purpose's cap, start with TrueType magic, and carry a table directory a renderer can read. A file that fails leaves the upload `rejected` with the failure's code, and attaching it again replays that code — so fix the file and create a new upload rather than retrying. Sending this to a font that already has a typeface replaces it. The previous file is deleted once the new one is committed, so any URL published for it stops resolving. The attach mints a fresh server-owned `font_file.family_name`, 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-font-file/
- Markdown URL: https://www.signcustomiser.com/help/api/v3-put-attach-a-font-file.md
- Group: Customiser fonts
- Method: PUT
- Path: /api/v3/customisers/{customiser_id}/fonts/{font_id}/file
- Auth: Bearer token
- Required scopes: `customisers:write`

## Path parameters

- customiser_id (string, required): The customiser id. Example: 1
- font_id (string, required): The font 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/fonts/11/file \
  --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": "font",
    "id": 11,
    "customiser_id": 42,
    "name": "Signature Script",
    "line_height": null,
    "uses_default_line_height": true,
    "stencil_safe": false,
    "min_height_smallest_letter_cm": null,
    "min_height_uppercase_letter_cm": null,
    "font_tier_id": 7,
    "length_pricing_id": null,
    "minimum_size_id": null,
    "minimum_legacy_fixed_height_size_id": null,
    "sort_order": 1,
    "font_file": {
      "has_font_file": true,
      "family_name": "kx7q2m9v4t1b8n6c3z5j0h2w4r7y1p6d",
      "ttf_url": "https://cdn.example.com/files/2f1c9c0e-6a7b-4c1d-8e2f-3a4b5c6d7e8f.ttf"
    },
    "created_at": "2026-08-13T00:00:00Z",
    "updated_at": "2026-08-13T00:05:00Z"
  },
  "links": {
    "self": "https://web.signcustomiser.com/api/v3/customisers/42/fonts/11/file",
    "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 font 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 Not a TrueType file

```json
{
  "type": "https://www.signcustomiser.com/help/api/problems/upload_content_type_mismatch",
  "title": "Upload content type mismatch",
  "status": 422,
  "code": "upload_content_type_mismatch",
  "detail": "The uploaded bytes are not font/ttf. The declared content type must match the file you send; upload the correct file under a new upload.",
  "errors": [
    {
      "pointer": "/upload_id",
      "code": "upload_content_type_mismatch",
      "detail": "The stored object is not font/ttf."
    }
  ],
  "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"
}
```