S~4s · works on any phone
SMS OTP: direct delivery to every Turkish carrier via NetGSM.
No app, no smartphone required. The widest-reach channel — and the default fallback when WhatsApp can't deliver.
From send to verify
1
Request
Either channel:"sms" explicitly, or a routing fall-through from WhatsApp.
2
Carrier delivery
Delivered through NetGSM straight to Turkcell, Vodafone and Türk Telekom.
3
Delivery report
Carrier DLR hits your webhook; undelivered messages are never billed.
4
Verification
5 attempts, 10-minute TTL. Codes stored as HMAC digests only.
$ curl -X POST https://api.kolayotp.com/api/v1/otp/send \
-H "Authorization: Bearer kotp_live_..." \
-d '{"channel":"sms","recipient":"+905551234567",
"sender":"KOLAYOTP","locale":"en"}'
{
"id": "otp_5Rt7wQ",
"channel": "sms",
"status": "sent",
"carrier": "turkcell",
"attempts_left": 5
}Channel specifications
ProviderNetGSM
Typical latency~4s
Unit price₺0.29 / OTP
Alphanumeric senderSupported
FallbackWhatsApp → Email
CoverageAll TR carriers
Send your first OTP in five minutes.
No credit card. Start on a sandbox key and switch to live when you're ready.