Voice OTP delivers a one-time password by automated voice call. It is a a complement to SMS for two-factor authentication. The call reads the code character by character, reaching audiences SMS may miss (elderly, visually impaired, fixed-line-only, SMS-unreachable destinations).
Voice OTP call scenario
Prompts for OTP can use Text-to-Speech (TTS). This can be plain text TTS or using SSML. Custom audio files are also supported. More information on the different types of prompts can be found at the Voice API prompts page. Mixing different types of prompts is possible. For instance, the code prompt, spelling the digits or letters, can use TTS prompts, while the other prompts can use custom audio files.
Webhook callbacks are available for OTP. For more information, visit the Voice API callbacks page.
Guides & API references
Use below links to get additional information to:
FAQ