# Setup Guide for Sinch SMS

This guide describes how to configure Sinch SMS for Acrobits Linkup Messaging.

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## 1. Service API Setup

1. Log in to the [Sinch dashboard](https://dashboard.sinch.com/).
2. In the left menu, go to **Messaging** > **SMS** > **Service APIs**.
3. Click your Service Plan to open its configuration screen.

![Sinch service API list](attachments/sinch-service-api-list.png)

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## 2. Retrieve Authentication Information

Copy the following values from the Service Plan configuration:

- Service Plan ID
- API token
- API endpoint region, for example United States or Europe

Send the API token securely. For example, you can use [One-Time Secret](https://eu.onetimesecret.com/).

![Sinch service plan authentication details](attachments/sinch-service-plan-authentication.png)

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## 3. Configure Callback URLs

1. Create a secure 32-character alphanumeric callback password without special characters.
2. Replace the placeholders in the following URLs:

   - Replace `{servicePlanId}` with the real Service Plan ID from the Sinch dashboard.
   - Replace `YOUR_PASSWORD` with the callback password.

   **Incoming Callback URL**

   ```text
   https://api-us.messaging.acrobits.cz/sinch/callbacks/{servicePlanId}/incoming-message?callbackPassword=YOUR_PASSWORD
   ```

   **Outgoing Callback URL**

   ```text
   https://api-us.messaging.acrobits.cz/sinch/callbacks/{servicePlanId}/message-status-update?callbackPassword=YOUR_PASSWORD
   ```

3. Configure both callback URLs in the Sinch Service Plan.
4. Use the same callback password for both callback URLs.

If you require Basic Authentication instead of the callback password query parameter, submit a request to Sinch support. Acrobits supports both authentication methods.

![Sinch callback URL configuration](attachments/sinch-callback-urls.png)

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## 4. Provide Configuration to Acrobits

Send the following information securely to Acrobits Support:

- Service Plan ID
- API token
- API endpoint region
- Callback password, either from the URL query parameter or Basic Authentication
- Callback user, required only if Sinch configures Basic Authentication for your callbacks

For 10DLC registration, also provide the following welcome message information:

- Brand
- Contact number
- Contact email
- Other contact information, such as a website

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## 5. Assign Virtual Numbers

In the **Numbers** section of Sinch:

1. Provision the required virtual numbers.
2. Assign the virtual numbers to the configured Service Plan.

![Sinch virtual numbers](attachments/sinch-virtual-numbers.png)