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Voice OTP

Secure voice-based OTP delivery at enterprise scale.

Deliver one-time passwords via automated voice calls. Higher reach than SMS OTP with 99.9% delivery rate across all networks and devices.

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99.9% Delivery
190+ Countries
1B+ OTPs/Year
Voice OTP Platform
Key Capabilities

Enterprise Voice OTP Features

Automated Voice Calls

OTP is read aloud via a clear, AI-generated voice call in the customer's preferred language. Multi-language support ensures every customer hears their code clearly.

Automatic Retry Logic

If the first call goes unanswered, automated retry logic dials again after configurable intervals. Ensure every user receives their OTP even during network disruptions.

Multi-Language Support

OTPs are read in 20+ languages including English, Hindi, Tamil, Telugu and more. Customers hear their code in a language they understand and ” improving authentication success rates.

Industry Use Cases

Voice OTP for Every Industry

See how enterprises use Voice OTP as a reliable fallback and primary authentication channel.

Banking Voice OTP

Voice OTP as Primary Channel for Senior Banking Customers

Many senior customers struggle with reading SMS OTPs quickly. Voice OTP delivers the code directly in a clear voice call and ” improving authentication success rates for elderly customers without any technical literacy barriers.

  • Spoken OTP delivery for senior and low-literacy customers.
  • Repeat option and ” customers can press a key to hear the OTP again.
  • Multi-language support for regional language banking customers.

Voice OTP Fallback for Failed SMS Delivery

When SMS OTP fails due to network issues, spam filters or phone DND settings, Voice OTP automatically triggers as a reliable fallback. Ensure every customer completes their transaction without contacting support.

  • Automatic SMS → Voice OTP fallback with configurable timing.
  • Higher delivery rate in rural and low-network areas via voice.
  • DND-bypass for Voice OTP on transactional banking calls.
Voice OTP Fallback
Banking Voice Analytics

Track OTP Call Success and Authentication Rates

Monitor call connection rates, OTP authentication success rates and fallback trigger frequency. Use analytics to optimise when Voice OTP is triggered and improve overall authentication completion.

  • Call connection rate and OTP success rate reporting.
  • Channel comparison and ” SMS vs Voice OTP success rates.
  • Authentication failure analysis and retry pattern reporting.
30% higher OTP success rate with Voice as a fallback channel
E-Commerce Voice OTP

Reduce Cart Abandonment with Higher OTP Success Rates

Failed OTP delivery at checkout is a major cause of cart abandonment. Voice OTP as a fallback ensures customers always receive their verification code, reducing checkout drop-off and increasing completed purchases.

  • Voice OTP auto-triggers when SMS OTP fails at checkout.
  • Faster verification for customers in poor network areas.
  • Reduce support tickets from customers who didn't receive SMS OTP.

Secure High-Value Orders with Voice Authentication

For high-value orders, use Voice OTP as a primary authentication channel for an additional layer of verification. The voice call confirms both identity and intent and ” reducing chargeback fraud on premium purchases.

  • Voice OTP as additional verification for large orders.
  • Fraud reduction with voice-based 2FA for high-risk transactions.
  • Customer confidence boost with proactive security verification.
High-Value Order Security
E-Commerce Analytics

Measure OTP Authentication and Conversion Impact

Track how Voice OTP fallback improves checkout completion rates. Compare authentication success with and without Voice OTP to quantify the revenue impact of improved OTP delivery.

  • Checkout completion rate improvement with Voice OTP.
  • OTP channel performance comparison analytics.
  • Revenue recovered through Voice OTP fallback reporting.
15% increase in checkout completion with Voice OTP fallback
Telecom Voice OTP

Reliable OTP Delivery Even Without Data Connectivity

Telecom and ISP customers changing plans or accessing portals often have connectivity issues. Voice OTP works even when internet and data are temporarily unavailable and ” ensuring seamless account access.

  • Voice OTP delivery over basic voice network without data.
  • Works in areas with 2G coverage where SMS may fail.
  • Ideal for service activation and plan change verification.

SIM Swap Verification via Outbound Voice OTP

Protect customers from SIM swap fraud by requiring voice OTP verification before processing SIM replacement requests. The voice call confirms identity without relying on the potentially compromised SIM.

  • Voice OTP for SIM swap request verification.
  • Number portability and plan upgrade authentication.
  • Customer self-service portal login via Voice OTP.
SIM Swap Security
Telecom Analytics

Track Voice OTP Performance Across All Use Cases

Monitor call success rates, OTP authentication completion rates and security incident prevention metrics. Use analytics to demonstrate the ROI of Voice OTP as a fraud prevention channel.

  • Call success rate and OTP completion rate by use case.
  • Fraud attempt detection and prevention reporting.
  • Cost savings from reduced fraud and support tickets.
99.9% Voice OTP delivery rate across all networks
Pricing Models

Choose a Plan Built for Your Scale

Growth Plan

Custom Pricing

Perfect for businesses needing Voice OTP as fallback.

  • Voice OTP API
  • 5 Language Support
  • Basic Analytics
  • No Dedicated Manager
BEST VALUE
Enterprise Pro

Volume Custom

Built for high-volume Voice OTP with advanced security.

  • 20+ Language Support
  • Smart Retry & Fallback
  • Fraud Detection
  • 24/7 SLA Support
Seamless Process

Start Delivering Voice OTPs in 3 Steps

1. Integrate the API

A single REST API call triggers a Voice OTP call. Full SDKs available in PHP, Node.js, Python and Java. Deploy in under 30 minutes.

2. Configure Call Settings

Set OTP length, expiry, retry intervals and preferred language. Configure as primary or fallback channel with SMS using our retry logic builder.

3. Deliver & Authenticate

Users receive a voice call with their OTP. Monitor call success and authentication rates from your real-time analytics dashboard.

EASY INTEGRATIONS

Connect Voice OTP to Your Authentication Stack

Nimbus Voice OTP integrates with your authentication systems, MFA platforms and business applications via REST APIs and ” delivering OTPs wherever users need them.

REST APIs JSON Webhooks
Shopify
WooCommerce
Salesforce
MFA Systems
Zoho CRM
Zapier
Google Sheets
Slack
Mailchimp
Pipedrive
Magento
Custom Auth

Ready to Add Voice OTP to Your Authentication?

Schedule a free demo and discover how Voice OTP can increase authentication success rates and reduce user frustration.

  • Free API integration and test numbers
  • Custom language and voice configuration
  • Dedicated account manager from day one

Request a Free Demo

Our team will reach out within 24 hours.

Got Questions?

Frequently Asked Questions

Everything you need to know about Voice OTP.

Voice OTP delivers a one-time password via an automated voice call instead of SMS. It is ideal when SMS delivery fails due to network issues, when customers have DND settings blocking SMS, when users are in low-connectivity areas, or as an additional authentication factor for high-security transactions.

Yes. Nimbus Voice OTP supports automatic fallback from SMS. If an SMS OTP fails to deliver within a configurable time window, the system automatically triggers a Voice OTP call to the same number and ” ensuring the user always receives their authentication code.

Nimbus Voice OTP supports 20+ languages including English, Hindi, Tamil, Telugu, Kannada, Bengali, Marathi, Gujarati and major international languages. The OTP is read clearly in the configured language, improving success rates for users who prefer their regional language.

You can configure the number of retry attempts, the interval between retries and the OTP repeat behaviour during a call. The system can retry up to 3 times with configurable wait periods, and during the call the OTP can be repeated multiple times if the user presses a key.