One-Time Passwords have become an essential part of digital authentication, as they are simple to use and widely available, with most users being used to them and feeling they are the familiar go-to options.
For a long time, SMS was the default channel for sending OTPs. Almost everyone has an active mobile phone and the process is easy to understand. This has evolved into using WhatsApp to deliver OTP messages faster, more reliably and through a platform that users already use every day, instead of the SMSs that were used widely in the past.
What Is WhatsApp OTP?
WhatsApp OTP is a one-time password sent to a user through WhatsApp to verify their identity. The OTP sent via WhatsApp is usually a short numeric code of 4 or 6 digits that expires after a limited time, and the user needs to quickly enter it inside an app, website or service to complete the verification process.
The main difference between sending OTPs via WhatsApp and SMS is the delivery channel. Instead of sending the code through the mobile carrier network, the business sends it through WhatsApp using the WhatsApp Business API, which is the only tool that supports bulk messaging users through WhatsApp.
Why Send OTP via WhatsApp Instead of SMS?
Sending OTP through WhatsApp can offer several advantages compared to traditional SMS, especially for businesses that deal with high volumes of authentication messages.
The first advantage is reliability. SMS delivery can be affected by carrier issues or weak network coverage. WhatsApp uses internet connectivity, whether through Wi-Fi or mobile data, which can make delivery more consistent for many users.
User familiarity is also another major advantage. WhatsApp is already part of everyday life for millions of users. Receiving an OTP through a familiar app can feel more natural than receiving it through a plain SMS message, especially when the WhatsApp message comes from a verified business account.
WhatsApp also supports a more branded experience. Instead of a random sender name or number, users can see the business logo, name and verification mark. This helps reduce confusion, scams and builds more trust during the authentication process.
Security is another important reason. WhatsApp messages are protected with end-to-end encryption, which means the message is encrypted between the sender and the recipient, unlike SMSs.
How to Send OTP via WhatsApp
Step 1: Get Access to the WhatsApp Business API
To send automated OTP messages on WhatsApp, you need access to the WhatsApp Business API. The regular WhatsApp Business App is not enough for this use case because it is designed for manual communication, not automated bulk messaging and advanced features.
Getting access to WhatsApp Business API can include several steps, but the outcome is definitely worth it. If you use an API supporting WhatsApp Business API for authentication like Authentica, you can overcome this hassle and start sending OTP messages via WhatsApp immediately.
Step 2: Create or Verify Your WhatsApp Business Account
Before sending authentication messages, your business needs a WhatsApp Business account. This includes verifying business details, connecting the phone number that will send messages, and making sure the business profile is clear and trustworthy.
Step 3: Create an Authentication Message Template
WhatsApp requires businesses to use approved message templates for OTP delivery. Templates are A requirement for any message sent via the API, no matter what it's content is.
A good OTP template should be short, clear, and direct. It should include the code, the purpose of the code, the expiry time and a warning not to share it with anyone.
Step 4: Connect the API to Your Backend
Once the template is approved, your development team needs to connect the WhatsApp Business API to the system that generates OTPs.
This means the backend should dynamically send the user’s phone number, the generated OTP, and any required template parameters to the API. The OTP should not be manually created or sent. It should be generated securely by your system and sent automatically when the user requests verification.
Step 5: Test the OTP Flow
Before rolling out WhatsApp OTP, testing is essential. You need to check that the OTP is generated correctly, delivered quickly, shown properly in the message, and verified accurately after the user enters it.
Testing should also cover failed attempts. For example, what happens when the code expires? What happens when the user enters the wrong code several times? What happens if WhatsApp delivery fails?
Final Thoughts
WhatsApp OTP is becoming a strong alternative to SMS OTP because it combines fast delivery, user familiarity, better branding, and enhanced security. In the blog, we have shared the steps to integrate WhatsApp OTP into your authentication flow. You should also consider overcoming the hassle of the steps with a ready to integrate API supporting WhatsApp OTPs like Authentica.