OTP and transactional notifications on every channel your users have
Deliver sign-in codes, payment confirmations and service alerts on WhatsApp with copy-code, one-tap or zero-tap templates, by SMS from a registered sender ID, by RCS, or by a voice call that reads the code aloud.
WhatsApp authentication message with a copy-code button. The code is sample data.
Short answer
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OmniChannels.ai delivers one-time passwords and transactional alerts on WhatsApp, SMS, RCS and voice. WhatsApp authentication templates offer copy-code, one-tap or zero-tap delivery. SMS goes out from a registered sender ID over BroadNet's operator connectivity, and voice OTP reads the code aloud, including in Arabic. You set a fallback order between channels, and delivery statuses reach your system by webhook. Your application generates and checks the code.
What OTP and notification delivery includes
WhatsApp authentication templates
Send codes in Meta's authentication format, with fixed preset text, an optional expiry line and a security reminder.
Copy-code, one-tap and zero-tap
Copy-code works on any phone. One-tap and zero-tap fill the code into your Android app and need integration work on your side.
SMS OTP from a registered sender ID
Reach users without WhatsApp or mobile data, using a sender ID registered for transactional traffic, with HLR lookup to check numbers.
RCS from a verified sender
Send codes from a verified, branded RCS sender on supported phones, with automatic SMS fallback where RCS is not available.
Voice OTP
A call reads the code aloud with text-to-speech, including in Arabic, for users who cannot receive messages or need accessibility support.
Fallback between channels
Set an order per flow, such as WhatsApp first, then SMS, then a voice call if delivery is not confirmed in time.
Delivery status for your system
Submitted, sent, delivered, read, failed and rejected events reach your backend by webhook, in one format for every channel.
Delivery reports
See status per message, filter by date and export to CSV to investigate slow or failed codes.
Which OTP delivery method fits your users?
Most teams offer more than one. The right mix depends on your audience, your app and your fraud risk.
| Item | Details |
|---|---|
| WhatsApp copy-code | A button copies the code for pasting into your app or website. No app changes needed. |
| WhatsApp one-tap | A button opens your Android app and passes the code. Needs Android app integration. |
| WhatsApp zero-tap | The code is passed to your Android app in the background with no tap. Needs Android app integration and Meta's terms. |
| SMS OTP | Works on any mobile phone without data. Needs a registered transactional sender ID in many markets. |
| RCS OTP | Branded, verified sender on RCS-capable phones, with automatic SMS fallback elsewhere. |
| Voice OTP | Code read aloud by text-to-speech, including Arabic. Provisioned with your account team. |
How to launch OTP delivery
Code generation and checking stay in your system. We plan delivery, fallback and reporting with you.
- 1
Map your verification flows
List where codes are sent, such as sign-up, login, password reset and payments, and the countries your users are in.
- 2
Set up the channels
Create a WhatsApp authentication template, register a transactional SMS sender ID, and arrange RCS and voice OTP if you need them.
- 3
Connect the API and webhooks
Call the REST API from your backend, choose the fallback order and point delivery webhooks at your system. Test access sends to your own verified numbers.
- 4
Add security and fraud controls
Set short expiry, single use, attempt limits, rate limits and country allow-lists in your application.
- 5
Test on real devices, then go live
Check delivery and timing on each operator and channel, then monitor how many codes are sent compared with codes entered.
Who should use OmniChannels.ai for OTP and alerts?
A good fit when
- You verify sign-ups, logins or payments by phone number.
- Your users are in markets where WhatsApp is common but some still need SMS or a voice call.
- You want delivery status per code so support can see why a user did not receive one.
- You send codes and service alerts in Arabic and English.
Good to know before you start
- OmniChannels.ai delivers codes; generating, storing and validating them is your application's job.
- Phone-based OTP is weaker than app-based authenticators or passkeys because of SIM-swap and interception risks.
- WhatsApp authentication templates cannot contain links, media or emoji, and their text is preset by Meta.
- Fallback can deliver more than one message for the same code; set wait times so users are not confused.
- Meta charges WhatsApp authentication messages by country, SMS is billed per segment and voice per call; confirm current rates.
Channel fallback, step by step
Send once through the platform or the API. If a step isn't delivered in time, the next channel takes over automatically, and every status comes back in one webhook format.
- 01
WhatsApp
Rich template with buttons, read receipts and replies in the inbox
- 02
RCS
Branded rich card where the handset and operator support RCS
- 03
SMS
Reaches every mobile phone over direct operator routes
- 04
Voice
A spoken code or message when text isn't getting through
OTP and notification questions
What is the difference between copy-code, one-tap and zero-tap?
Copy-code shows a button that copies the code for the user to paste. One-tap opens your Android app and passes the code. Zero-tap passes the code to your Android app with no tap. One-tap and zero-tap need Android app integration; copy-code does not.
When should we use voice OTP?
Use a voice call as a last fallback when a message is not delivered, for landline numbers, or for users who prefer to hear the code. The call reads the code aloud with text-to-speech, including in Arabic.
How long should a code be valid?
Keep it short and accept each code only once. NIST guidance limits out-of-band authentication to 10 minutes, and many businesses use shorter windows for logins and payments. WhatsApp authentication templates can show an expiry line so users know the deadline.
What is SMS pumping and how do we prevent it?
SMS pumping, or artificially inflated traffic, is fraud where bots request codes to numbers that earn the attacker a share of the fees. Prevent it in layers: bot checks before sending, allowing only countries you serve, rate limits per number and IP, and alerts when codes sent rise without codes entered.
Which channel should we send OTPs on first?
It depends on your users. WhatsApp offers a branded message with copy-code or autofill where users have data. RCS gives a verified sender on supported phones. SMS reaches almost any phone, and voice covers the rest. Many teams start on one and fall back to the next.
Can we put a sign-in link in a WhatsApp OTP?
No. Meta's authentication templates cannot contain links, media or emoji. Send links in a separate utility template if your flow needs one.
Guides on this topic
- SMS & OTPOTP Messages on WhatsApp and SMS: Security, Delivery and Fraud9 min read
- SMS & OTPSMS Pumping Fraud: How AIT Works and How to Stop It9 min read
- UAE & Saudi ArabiaSMS Sender ID Registration in the UAE and Saudi Arabia Explained8 min read
- WhatsAppWhatsApp Template Categories, Approval and Recategorization8 min read
- MarketingBanking and Fintech Customer Messaging: Alerts, OTP and Fraud8 min read
- MarketingSent vs Delivered vs Read vs Failed: Message Status Explained8 min read
Explore more of the platform
Plan your OTP delivery with our engineers
Tell us your verification flows, markets and volumes. We'll review channels, fallback, delivery status and fraud controls with you.