Top Emerging Channels for OTP Delivery in 2025: Beyond SMS
Published: Jul 3, 2025
One-time passwords (OTPs) remain a crucial pillar of digital security and user verification. While SMS OTP has long been the go-to channel, 2025 marks a turning point: businesses are increasingly adopting new, faster, and more user-friendly channels to deliver OTPs.
At Dexatel, we've seen firsthand how diversifying verification channels improves user experience and conversion rates. Let's explore the top emerging OTP channels that will shape the future of authentication.
SMS OTP: The Trustworthy Classic
SMS remains the most widely used OTP channel worldwide. Its global reach and familiarity make it an essential part of any verification strategy. However, challenges like delivery delays and SIM swap fraud have pushed companies to look beyond SMS.
The Numbers Behind SMS OTP
Universal reach: Available on 99.9% of mobile devices globally
High open rates: 98% of SMS messages are read within 3 minutes
Cross-generational appeal: Equally effective across all age demographics
Infrastructure maturity: Established delivery networks in 195+ countries
Challenges and Limitations
Delivery Inconsistencies: Network congestion can cause delays, particularly during peak usage periods or in areas with poor cellular coverage. In emerging markets, delivery failures can reach 15-20% during high-traffic periods.
Security Vulnerabilities: SIM swap attacks have become increasingly sophisticated, with fraudsters gaining access to phone numbers to intercept OTPs. The FBI reported over 320 million dollars in losses from SIM swap fraud in 2024 alone.
Cost Considerations: International SMS delivery costs can be prohibitive for global businesses, with premium route pricing ranging from $0.05 to $0.15 per message in certain regions.
WhatsApp OTP: The New Favorite
With over 2 billion users globally, WhatsApp has become a powerful channel for real-time communication. Businesses are increasingly using WhatsApp OTP to provide faster, more reliable authentication — especially in regions where WhatsApp is a primary messaging app. Users trust it and engage with it actively, making it ideal for seamless verification flows.
Why WhatsApp is Gaining Momentum
Instant Delivery: WhatsApp messages are delivered over internet connections, typically arriving within seconds compared to SMS which can take minutes.
Enhanced Security: End-to-end encryption provides an additional security layer that traditional SMS lacks. The platform also offers two-factor authentication for account protection.
Rich Media Support: Unlike SMS, WhatsApp allows businesses to include branding elements, images, and formatted text in their OTP messages, improving brand recognition and trust.
Global Penetration: In markets like India, Brazil, and across Latin America, WhatsApp penetration exceeds 85% of smartphone users, making it more accessible than traditional SMS in many regions.
Implementation Best Practices
Business API Integration: Companies must use WhatsApp Business API to send OTPs, which requires pre-approval and adherence to messaging policies.
Template Compliance: All OTP messages must use pre-approved templates that comply with WhatsApp's business messaging guidelines.
Fallback Strategy: Despite high reliability, businesses should implement SMS fallback for users who haven't opted into WhatsApp business messaging.
Cost Optimization: WhatsApp Business API pricing varies by region, typically ranging from $0.005 to $0.09 per message, often providing cost savings compared to premium SMS routes.
Telegram OTP: Growing with Privacy-Focused Users
Telegram is rapidly gaining ground as a verification channel, particularly among tech-savvy and privacy-conscious audiences. Its strong encryption and fast delivery make it a promising alternative to traditional SMS.
The Telegram Advantage
Speed and Reliability: Built on a cloud-based infrastructure, Telegram messages are delivered instantly across devices, with 99.7% delivery success rates in most markets.
Cross-Device Synchronization: Unlike SMS, Telegram OTPs can be accessed across multiple devices, providing flexibility for users who switch between phones, tablets, and computers.
Enhanced Privacy: Telegram's focus on privacy appeals to users concerned about data security, with features like self-destructing messages and secret chats.
Bot Integration: Telegram's robust bot API allows for sophisticated OTP delivery mechanisms, including interactive verification flows and custom user experiences.
Market Adoption and Demographics
Telegram's user base has grown to over 900 million active users globally, with particularly strong adoption in:
Eastern Europe: 40%+ market penetration
Middle East: 35%+ market penetration
Tech communities: High adoption among developers and crypto users
Privacy-conscious segments: Growing preference among users concerned with data privacy
Technical Implementation Considerations
Bot Development: Businesses need to create and maintain Telegram bots for OTP delivery, requiring technical expertise or third-party integration services.
User Onboarding: Unlike SMS which works universally, Telegram OTP requires users to have the app installed and to initiate contact with the business bot.
Compliance Requirements: Different regions have varying regulations regarding bot communications and data handling.
Voice OTP: Accessibility and Reach
Voice OTPs deliver a one-time password via an automated phone call, expanding reach to users with limited internet connectivity or those who prefer voice interaction. Voice OTP is especially useful for regions where smartphone penetration is lower or data connectivity is unreliable.
Expanding Accessibility Through Voice
Universal Device Compatibility: Works on any phone, including basic feature phones and landlines, making it ideal for emerging markets where smartphone adoption is still growing.
Accessibility Compliance: Provides essential verification access for visually impaired users and those with reading difficulties, helping businesses meet accessibility standards.
Network Independence: Functions over traditional voice networks, providing reliability in areas with poor data connectivity but stable cellular voice coverage.
Multilingual Support: Advanced text-to-speech technology can deliver OTPs in multiple languages and regional dialects, improving user comprehension.
Use Cases and Market Applications
Financial Services: Banks and fintech companies use voice OTP for high-value transactions, providing an additional verification layer that feels more secure to users.
Healthcare: Medical platforms leverage voice OTP for patient verification, especially important for telehealth services serving older demographics.
Government Services: Digital government initiatives often implement voice OTP to ensure inclusive access to online services.
Rural and Remote Areas: Essential for reaching users in areas where internet connectivity is unreliable but voice networks are stable.
Technical Implementation and Costs
Infrastructure Requirements: Requires integration with voice service providers and call routing systems, typically more complex than SMS or messaging app integration.
Cost Structure: Voice calls generally cost more than SMS, ranging from $0.02 to $0.25 per minute depending on the destination country and quality requirements.
Delivery Time: Voice OTPs take longer to deliver than text-based alternatives, typically requiring 30-60 seconds for call connection and message playback.
Quality Assurance: Success depends on call audio quality, background noise levels, and user availability to answer calls.
Regional Preferences and Market Analysis
North America and Europe
SMS remains dominant (75% of implementations)
Growing adoption of app-based authentication (20%)
WhatsApp usage increasing in specific demographics
Asia-Pacific
WhatsApp dominates in India and Southeast Asia (60%+)
Telegram popular in tech-forward markets
Voice OTP essential for rural populations
Latin America
WhatsApp is the preferred channel (70%+)
SMS used primarily as fallback
Voice OTP important for financial services
Middle East and Africa
Mixed adoption based on local messaging app preferences
Voice OTP crucial for reaching unbanked populations
SMS remains reliable in areas with limited internet
Security Comparison: Evaluating Channel Safety
SMS OTP: Medium security due to SIM swap vulnerabilities, but benefits from network-level encryption during transmission.
WhatsApp OTP: High security with end-to-end encryption, but requires users to trust Meta's infrastructure and policies.
Telegram OTP: High security with strong encryption, though cloud-based storage raises some enterprise compliance questions.
Voice OTP: Medium security, vulnerable to call interception but generally more secure than SMS against SIM swap attacks.
Best Practices for Secure Implementation
Short OTP validity periods (2-5 minutes)
Rate limiting to prevent brute force attacks
Multi-channel verification for high-value transactions
Comprehensive logging and monitoring
Regular security audits and penetration testing
Cost Analysis: Understanding the Economics
Comparative Cost Structure
SMS: $0.01-$0.15 per message depending on route quality and destination WhatsApp: $0.005-$0.09 per message via Business API Telegram: Typically free for bot messages, with potential hosting costs Voice OTP: $0.02-$0.25 per call based on duration and destination
Hidden Costs to Consider
Integration and development expenses
Maintenance and monitoring infrastructure
Customer support for delivery issues
Compliance and regulatory requirements
Fallback channel implementation
Implementation Strategy: Building a Multi-Channel Approach
Channel Selection Framework
Primary Channel: Choose based on target demographic and regional preferences
Secondary Channel: Implement fallback for delivery failures
Premium Channel: Reserve for high-value transactions or VIP users
Accessibility Channel: Ensure inclusive access through voice or alternative methods
Technical Architecture Considerations
Unified API for channel management
Real-time delivery status monitoring
Automatic failover mechanisms
Analytics and reporting capabilities
A/B testing infrastructure for optimization
The Future of User Verification
2025 is all about flexibility and user preference. By offering a multi-channel verification experience, businesses can maximize security while reducing friction in the sign-up and login processes.
Emerging Trends to Watch
Biometric Integration: Combining OTPs with fingerprint, facial recognition, or voice authentication for enhanced security.
Artificial Intelligence: AI-powered fraud detection that dynamically selects the most secure channel based on risk assessment.
Blockchain Verification: Decentralized authentication systems that could revolutionize how we think about identity verification.
Quantum-Resistant Security: Preparing for the future of cryptography with quantum-safe OTP generation and delivery methods.
At Dexatel, our Verify API solution supports OTP delivery across all major channels — SMS, WhatsApp, Telegram, Voice, and more — so you can meet your customers where they are.
Key Takeaways for Business Leaders
Diversification is Essential: No single channel can meet all user needs and preferences
Regional Customization: Success requires understanding local market preferences and infrastructure
Security First: Channel selection must balance user experience with robust security requirements
Cost Optimization: Multi-channel strategies can actually reduce overall verification costs through improved delivery rates
Future-Proofing: Investment in flexible, API-driven solutions enables adaptation to emerging technologies
