A missed call is the code.
The user receives a brief incoming call. The last 4 digits of the caller ID are the OTP. No answer needed. No SMS cost. Highest completion rate of any verification channel.
Verification at the lowest possible cost.
FlashCall turns a declined call into an OTP — no airtime, no SMS fee, no data connection required.
No recipient cost
The call is declined automatically. No airtime charge for the user, no SMS fee for you.
Works offline
Unlike app-based OTP, FlashCall works on any phone with a signal — no data connection needed.
Instant recognition
Users read 4 digits from the missed-call notification on their lock screen. Zero friction, no typing delays.
Fallback chain compatible
FlashCall plugs into the same /v1/verify/send endpoint as all other channels.
Global reach
Available in all countries where the voice network operates.
Fraud resistant
Number spoofing is detectable. Each FlashCall uses a unique caller ID per session.
Where FlashCall wins outright.
High-volume mobile verification
Lowest cost-per-verification for large-scale user bases with mobile numbers.
ScaleNo-data environments
Rural users, low-end devices, or any scenario where SMS delivery is unreliable.
ReachFallback for SMS failure
Configure as the first fallback after SMS in markets where SMS delivery rates are lower.
FallbackOne channel value. Same verify endpoint.
Add flashcall
Include flashcall in your channel chain on /v1/verify/send.
User gets a missed call
The call is declined automatically — the last 4 digits are the code.
Check as normal
Confirm with /v1/verify/check, exactly like any other channel.
The code that costs nothing to deliver.
Add FlashCall to your fallback chain today and cut your verification spend.