> ## Documentation Index
> Fetch the complete documentation index at: https://www.charitystack.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# PUT /v1/forms/{formID}/links/{linkID} — update a prefilled checkout link

> Replace a link's name, prefill payload, destination type, and overlay path. Full-record semantics — any field omitted from the body is treated as cleared, not preserved.

The Update Link endpoint replaces the editable fields of an existing link. It uses **full-record semantics**: fields omitted from the body are cleared, not preserved. If you want to keep existing values, include them explicitly in the request.

Audit fields (`createdAt`, the original creator) and the link's `active` state are preserved across updates. To flip `active`, use [Activate](/docs/api/forms/toggle-link) or [Deactivate](/docs/api/forms/toggle-link) instead.

The parent form cannot be changed — the `formID` in the URL must match the link's stored parent.

## Endpoint

```text theme={null}
PUT https://0k90mc4jjj.execute-api.us-east-2.amazonaws.com/v1/forms/{formID}/links/{linkID}
```

## Authentication

<ParamField header="Authorization" type="string" required>
  Bearer token using your API key. Format: `Bearer cs_live_your_key`
</ParamField>

## Path parameters

<ParamField path="formID" type="string" required>
  The parent form's unique identifier.
</ParamField>

<ParamField path="linkID" type="string" required>
  The link's unique identifier.
</ParamField>

## Request body

The request body is identical to [Create Link](/docs/api/forms/create-checkout-link) — `name`, `destinationType`, `overlayPath`, and the full `prefill` object are all supported. The same validation rules apply.

When `destinationType` changes between `HOSTED_PAGE_*` and `OVERLAY_*`, `overlayPath` becomes required (for overlay) or is cleared (for hosted-page). The `destinationType` must remain compatible with the form's type — you cannot change a HOSTED\_PAGE\_DONATE link to HOSTED\_PAGE\_ATTEND on a non-EVENT form.

## Response

Same shape as [Get Link](/docs/api/forms/get-link). Returns the updated state.

## Status codes

| Code  | Description                                                                                                |
| ----- | ---------------------------------------------------------------------------------------------------------- |
| `200` | Link updated.                                                                                              |
| `400` | Validation error (same set as create).                                                                     |
| `401` | Missing or invalid API key.                                                                                |
| `403` | Link or form belongs to a different organization.                                                          |
| `404` | No link found with the given ID, or not attached to the supplied `formID`, or the parent form was deleted. |
| `410` | Parent form has been deleted.                                                                              |
| `500` | Internal error.                                                                                            |

## Example

```bash cURL theme={null}
curl -X PUT https://0k90mc4jjj.execute-api.us-east-2.amazonaws.com/v1/forms/{formID}/links/{linkID} \
  -H "Authorization: Bearer cs_live_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Outreach email — May 2026 (updated)",
    "prefill": {
      "firstName": "Akif",
      "lastName": "Abidi",
      "email": "akif@example.org",
      "amount": 75,
      "frequency": "MONTHLY"
    }
  }'
```

**200 response**

```json theme={null}
{
  "linkID": "bc033789-1ee2-4f3f-bec5-2f108c2d65ba",
  "formID": "550e8400-e29b-41d4-a716-446655440000",
  "name": "Outreach email — May 2026 (updated)",
  "checkoutUrl": "https://charitystack.com/donate/550e8400-e29b-41d4-a716-446655440000?elementid=bc033789-1ee2-4f3f-bec5-2f108c2d65ba",
  "destinationType": "HOSTED_PAGE_DONATE",
  "overlayPath": "",
  "active": true
}
```