WhatsApp Auth

WhatsApp zero-tap. Login before they look down.

An OTP arrives through WhatsApp. The SDK reads it on-device and submits it automatically — no copy-paste, no app switch. The user just watches it complete.

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Enter the code sent to +91 91060 18026 on WhatsApp.
Reading from WhatsApp…
Resend code in 0:24
You're in.
verified · 2.1s · 0 taps
Enter number · auto-read · auto-submit · ~2s
0
User taps required
7s
P90 delivery
95%+
Android auto-read
30+
Global coverage
Why WhatsApp Auth

The OTP you send today is costing you more than money.

SMS is the default no one re-examines — expensive, leaky, gamed by fraud, and anonymous. Line them up and the case makes itself.

Compared on
SMS OTP
The legacy default
Cost per login
Premium rates, worst where you grow
Delivery
Carrier-dependent, queues & delays
Deliverability
Filtered, throttled, lost to spam
Fraud exposure
AIT inflation & SIM-swap interception
Who it's from
Anonymous shortcode
On your brand

Auth that looks like you, in the app they trust.

An SMS shortcode is a stranger asking for a code. A WhatsApp message comes from your verified business — your name, your logo, a green tick — delivered in the app 2 billion people open every day.

2B+
People on WhatsApp
Verified
Business sender
2-way
Channel, not a dead end
SMS · unknown shortcode
#
QP-ACMOTP
Text message · sender unverified
<#> 418302 is your code. Do not share it with anyone. Reply STOP to opt out. t.ly/x9k2
9:43 AM · delivered late
How zero-tap works

Six steps behind the scenes. A code that fills itself up front.

The user taps once, then watches the code arrive and auto-fill. The whole signed handshake runs underneath — tap to verified, in milliseconds.

Elapsed Behind the scenes What the user sees
T+0ms User taps Continuesign-in screen tapped Signing in…
T+50ms SDK posts to OTPless edgeapp hash bound to request Signing in…
T+120ms WhatsApp Business API acceptsauth template dispatched Signing in…
T+1.9s OTP delivered to devicesilent · no notification OTP screen opens
T+1.95s SDK auto-reads the OTPextracted on-device 418302 Auto-fills
T+2.1s OTPless returns a signed tokenverified server-side Welcome.
P50 ~2s · P90 ~7s · India · Q1 2026 0 taps · 0 notifications · 0 app switches
Integration

One call. WhatsApp delivered, read, and verified.

You pass a phone number and your app's signing hash. OTPless dispatches the WhatsApp template, the SDK auto-reads the code on-device, and your backend gets a signed token.

SignInActivity.kt android · kotlin 
import com.otpless.main.OtplessManager
import com.otpless.dto.HeadlessRequest
import com.otpless.dto.HeadlessResponse

// 1. Init the OTPLESS view in your sign-in activity
private val otplessView = OtplessManager
    .getInstance().getOtplessView(this)

// 2. Verify over WhatsApp — phone + your app hash
val request = HeadlessRequest()
request.setPhoneNumber("91", "7069914791")
request.setChannel("WHATSAPP")        // zero-tap, auto-read

// 3. Start headless auth — OTPless reads the code on-device
otplessView.startHeadless(request, ::onHeadlessCallback)

private fun onHeadlessCallback(res: HeadlessResponse) {
    if (res.statusCode == 200 &&
        res.responseType == "ONETAP") {
        val token = res.response.optString("token")
        // → verify token on your backend
    }
}
// build.gradle  implementation 'io.github.otpless-tech:otpless-android-sdk:2.5.3'
onHeadlessCallback · ONETAP
1.9s
auths[0] · primary
channelWHATSAPP_OTP
statusSUCCESS
autoReadtrue
verifiedAt1778612141195
delivery
templatesent
latency1.94s
appHashbound
notificationnone
device: iQOO I2410 · Android 16 region: in
Customer Outcomes

The numbers our customers ship with.

* Metrics measured against pre-OTPless baselines.

20×
Lower intl. auth cost
"OTPless made login effortless for our users and simpler for our team. WhatsApp zero-tap and smart fallback boosted conversions and cut our international auth costs by 20×."
SG
Sagar Gaonkar
CTO · EloElo
25M+
Logins / month
"OTPless completely transformed how users log in at Meesho — fast, effortless, and frustration-free. Over 25 million seamless logins every month and a 10% boost in conversion."
Arjit Verma · Associate Director · Meesho
94.1%
Login success
Ankit Bhatia
Product Head · Seekho
6M+
Logins / month
Vishesh Upparamani
PM · Classplus
98%+
Login success
"Astrotalk partnered with OTPless to simplify login, reduce operational complexity, and support international scale. Zero-touch flows and intelligent routing delivered measurable impact on conversion, cost, and experience."
Siddharth Singh
CTO · Astrotalk
Frequently asked

Common questions.

What is OTPless WhatsApp Auth?
WhatsApp Auth delivers your login OTP through WhatsApp instead of SMS. On Android the SDK auto-reads the code on-device and submits it for the user — zero taps, sub-second verification. It's cheaper than SMS, lands more reliably, and carries your verified business identity.
How does the zero-tap auto-read work?
The WhatsApp message is bound to your app via its SHA-256 signing hash. When it arrives, WhatsApp hands the code straight to the OTPless SDK — no notification, no chat thread, no app switch. The SDK submits it to OTPless, which verifies server-side and returns a signed token.
Which platforms support auto-read?
Android achieves 95%+ silent auto-read across India, LATAM, MENA, and SEA. On iOS, where the WhatsApp-to-app callback isn't exposed, the SDK falls back to a system autofill suggestion on the keyboard — one tap, no manual typing.
Is WhatsApp really cheaper than SMS?
Yes — up to 20× cheaper per verification, with the gap widest on international traffic where SMS termination rates are highest. You also avoid SMS-pumping and AIT fraud that inflates SMS bills.
What if the user doesn't have WhatsApp?
WhatsApp Auth runs inside OTPless Mobile Auth, which picks the best channel per request. If WhatsApp isn't available or degrades, it falls back automatically to SMS, SNA, or Voice — no extra code on your side.
How long does integration take?
About 30 minutes. The SDK supports iOS, Android, Web, React Native, Flutter, and Ionic, plus a plain HTTP API — the same call shape across all platforms.
Start with WhatsApp Auth

Stop paying the SMS tax. Authenticate on WhatsApp.

Cheaper, faster, fraud-resistant, and on your brand — in the app 2 billion people already trust. Most teams ship within a week.

Talk to our team Read the docs
SOC 2 · ISO 27001 · 500M+ logins / quarter