> For the complete documentation index, see [llms.txt](https://guides.d7networks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guides.d7networks.com/verify/start-using-verify.md). # Start using Verify Ensure security with the Verify OTP. Explore its features, configuration options, and guidelines for effective user verification. ### Features **OTP Generation** * **Automatic Generation**: OTPs are generated automatically and are unique for each verification attempt. * **Custom Length**: Users can configure the length of the OTP (must be between 2 to 10 digits). #### OTP Delivery * **Delivery Methods**: OTPs can be sent to users via SMS, WhatsApp, or Voice call. * **SMS Delivery**: The OTP is sent to the user's registered mobile number. * **WhatsApp Delivery**: The OTP is sent to the user's registered WhatsApp number. * **Voice Delivery:** The user receives an automated phone call on their registered mobile number, and the OTP is read out to them. * **Registered Sender ID for SMS**: To make use of the Verify OTP feature via SMS, the user must have a registered Sender ID. * **Registered Business Phone Number for WhatsApp**: To make use of the Verify OTP feature via WhatsApp, the user must have a business phone number and an authentication template registered with Meta. * **Voice Call Configuration:** No Sender ID or template registration is needed for Voice. When setting up a Verify flow, the user can choose the voice language and gender, customise the voice message, and use Test Call to hear the message before saving (requires a verified mobile number on the account). #### OTP Validation * **Validation Window**: Configurable time window during which the OTP is valid (e.g., 5 minutes). * **Retry Attempts**: Limit on the number of allowed retry attempts for entering the OTP. The Verify OTP feature enhances security by adding an extra layer of verification. By following the configuration and usage guidelines, users can effectively utilize OTP for secure authentication processes. Ensure that a registered Sender ID is in place for SMS delivery to maintain compliance and reliability. For a comprehensive understanding and to see the feature in action, test it from our dashboard and refer to the video demonstration provided. **OTP Verification via SMS** {% embed url="" %}