Landline Direct Call · Anti-Fraud · High Security

Voice OTP
Landline Direct Call Broadcast

Landline calls user's mobile to broadcast OTP, eliminating SMS blacklist and delivery blind spots

Voice messages are difficult to intercept — more secure than SMS; independent of SMS channels with 100% user coverage

99%
Delivery Rate
<15s
Response
0.06¥
Starting
100%
Real-Name Verified
Free Trial View Pricing

Three Key Scenarios · Critical Operation Protection

When SMS OTPs encounter blind spots, voice OTP is the best backup solution

User Registration

Broadcast OTP via voice during new user registration
Prevent fraudulent registrations and fake signups
Ensure genuine user onboarding

New RegistrationAnti-FraudIdentity Verify

Payment Confirmation

Large payments/transfers and other security scenarios
Verify identity via voice broadcast confirmation code
Prevent payment interception and tampering

Payment VerifyTransfer ConfirmPassword Reset

Critical Notifications

Account anomalies, remote logins, security alerts
Urgent notifications ensure users are promptly informed
Reduce latency risks from SMS interception

Security AlertAccount ReminderImportant Notice

Voice OTP vs. SMS OTP

Complementary solutions: Use both to achieve 100% user coverage

Voice OTP

✓
Bypasses SMS Blacklists

Not affected by user SMS blocks or blacklists

✓
Anti-Interception

Direct phone call, voice messages are hard to intercept

✓
Instant Attention

Incoming call alert grabs user attention immediately

✓
Real-Name Landline

Real-name registered landline numbers build user trust

✗
Slightly Higher Cost

From 0.06¥/msg, suitable for critical scenarios

SMS OTP

✓
Lower Cost

From 0.036¥/msg, ideal for high-volume scenarios

✓
Faster Speed

Arrives within 5 seconds, minimal user wait time

✓
Massive Concurrency

10K-level concurrency for traffic peaks

✓
User Familiarity

Users are highly accustomed to SMS OTPs

✗
May Be Blocked

Users may have SMS filtering/blacklists enabled

💡 Recommended:SMS + Voice dual-channel. Auto-fallback to voice when SMS fails, ensuring 100% delivery

Why Choose Baichuan Cloud Voice OTP

🛡

Anti-Fraud & Anti-Theft

Direct landline call broadcasts OTPs, preventing interception and effectively blocking fraud and fake orders

📡

99% Delivery Rate

Immune to SMS blacklists and blocking apps. Direct carrier landline network ensures every call gets through

🔗

Simple API Integration

Standard RESTful API with multi-language SDKs (Java/Python/PHP/Go). Integration in 10 minutes

🔄

SMS Fallback Backup

Dual-channel auto-switching: SMS failure triggers voice broadcast automatically, ensuring 100% coverage

How Voice OTP Works

Fully automated from request to broadcast, no manual intervention needed

1

Initiate Request

User triggers OTP,
server calls API

2

Generate OTP

System generates unique OTP
Dynamically encoded, time-limited

3

Landline Call

Real-name landline calls user
Broadcasts OTP content

4

Verification Complete

User enters the OTP
Verified, callback notification

Frequently Asked Questions

Which is better, voice OTP or SMS OTP?
Voice OTP broadcasts codes via landline direct calls, ideal for user registration, payment confirmation, and other critical operations with stronger anti-theft security. SMS OTP is better for routine verification with lower cost. Recommended approach: use both — default to SMS with automatic voice fallback when SMS delivery fails, ensuring 100% delivery rate.
How is voice OTP billed?
Voice OTP is billed per message, starting at 0.06¥/msg. Higher volume means better pricing with tiered discounts. New users receive free trial credits upon registration. Check the Pricing page or contact customer service for more offers.
What languages does voice OTP support?
Mandarin Chinese broadcast is supported by default with clear and natural voice quality. English and other languages can be customized on demand to meet international business needs. Contact customer service for special language requirements.
How to integrate the voice OTP API?
Baichuan Cloud provides standard RESTful API with multi-language SDK support (Java, Python, PHP, Go). Integration steps:
① Register to obtain API credentials (AccessKey/SecretKey);
② Download the SDK for your language or call HTTP endpoints directly;
③ Configure recipient phone number and OTP template;
④ Call the send endpoint to start. Full documentation at Documentation Center.
What is the delivery rate for voice OTP?
Voice OTP has a delivery rate of 99%+. Unlike SMS OTP, voice OTP is not affected by user SMS blacklists or blocking settings. It dials users directly through the landline network — the call connects as long as the user's phone is powered on with signal. Automatic retry mechanisms further ensure delivery.

Start Using Voice OTP Today

Register for free trial credits and experience landline direct-call, anti-fraud OTP verification

Free Registration 400-0754-688
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