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

# Custom Sender IDs

> Send verification messages through your branded sender ID.

A **sender ID** is the name or number that appears as the "from" of a verification message — the thing your user sees before they even open it. By default, Prelude routes messages through pre-registered shared sender IDs optimized for deliverability. If you'd rather show your own brand name (like `ACME`) or a dedicated long code, you can configure a custom sender ID on your account.

Prelude allows you to send verification messages through your branded sender ID. This is useful when you want to send verification messages through a number that is associated with your brand.

<Note>
  Regulations for sender IDs vary by region. In some regions, you may need to register your sender ID with the relevant authority before you can use it.

  Extra fees may apply for registering and maintaining your sender ID.

  Contact our [support team](mailto:support@prelude.so) to get more information about the sender ID regulations in your region.
</Note>

<Info>
  Alphanumeric sender IDs are **not** supported in the United States and Canada.
</Info>

There are two ways to use a sender ID:

1. Through an account-level sender ID that is applied to all your verification requests.

   [Contact our support team](mailto:support@prelude.so) to enable a default sender ID on your account.

2. Through a request-level sender ID that is applied to a specific verification request.

   You can set a request-level sender ID by setting the `options.sender_id` parameter on the [`POST /v2/verification`](/verify/v2/api-reference/create-or-retry-a-verification) endpoint.

   <ParamField body="options.sender_id" type="string">
     The sender ID to use for the verification request.
   </ParamField>

   The sender ID specified in the request must be a valid, whitelisted sender ID for your account. To add a sender ID to your account, [contact our support team](mailto:support@prelude.so).