00Flagship product

One API call. Three channels. Until the code lands.

MsgBridge Verify cascades a one-time code across SMS, WhatsApp and voice — so a stuck OTP never costs you a signup.

02MsgBridge Verify

SMS, then WhatsApp, then a voice call.

One API call runs the whole cascade until the code lands — SMS first, then WhatsApp, then a voice call — so more users finish signup and login.

  1. Request received

    One call to /v1/verify/start

  2. SMS

    Code sent on the transactional route

  3. No deliverytimeout

    Nothing confirmed in 12 seconds

  4. WhatsApp

    Falling back to the template message

  5. Not readtimeout

    No read receipt in 15 seconds

  6. Voice call

    Automated call reads the code aloud

  7. Verified

    Code entered — one webhook, one charge

Explore Verify
9:41

POST /v1/verify/start → 202 accepted

channel=sms status=sent

channel=sms status=undelivered t=12s

channel=whatsapp status=sent

channel=whatsapp status=unread t=15s

channel=voice status=answered

verification=complete via=voice

02The problem

SMS OTP delivery doesn’t always land.

Network congestion, DND misconfiguration, a handset with a full inbox, a user roaming abroad — any one of these turns a one-time password into an abandoned signup. Every channel has a failure mode. Verify’s answer is to not depend on just one.

04The API

One request starts the cascade. One webhook tells you how it ended.

curl https://api.msgbridge.in/v1/verify/start \  -H "Authorization: Bearer $API_KEY" \  -d to="+91XXXXXXXXXX" \  -d channels="sms,whatsapp,voice" \  -d code_length="6" \  -d ttl_seconds="300"

05Configuration

Channel orderSMS → WhatsApp → Voice (configurable)
Per-step timeout12–20 seconds, set per channel
Retry countUp to 2 retries per channel before falling back
Code length & TTL4–8 digits, 5–10 minute expiry
Voice languageen-IN, hi-IN and regional languages

07Who it's for

FintechBankingE-commerceHealthcareEducationDelivery apps

09FAQ

One call. You send a single verification request and MsgBridge orchestrates the cascade — you don't call SMS, then WhatsApp, then Voice yourself.

The completion webhook tells you which channel succeeded, along with timestamps for every attempt in the cascade.

Yes. Channel order and count are configurable per project — run SMS → Voice only, or WhatsApp-first if that suits your user base.

You get an exhausted-cascade webhook so your product can offer an alternative path, such as a support callback.

It sits alongside it. Point verification traffic at the Verify endpoint and keep using OTP SMS directly for flows that don't need failover.

Per successful verification — a cascade that tries all three channels counts the same as one that succeeds on the first, so retries across channels don't multiply what you pay.

Stop losing signups to a stuck OTP

Get sandbox credentials for MsgBridge Verify today.