One-time code by SMS

Confirm that a person owns a phone number: send a code by SMS, then check what they type.

There are two ways.

	You make the code (recommended)	We make the code
Calls	Send SMS	Send a verification code, then Check a verification code
The SMS text	Any text you write	The 4-digit code alone
Who checks the code	You do	We do
Best for	Your own wording, your brand in the text, your own code length and rules	A quick first test

Way 1: you make and check the code

Make a code and remember it

Make a random code on your server, for example six digits, with a secure random generator. Keep it with the
person's session together with the time and a counter of wrong tries.

Send it

Send it in your own text with sms_type set to T, which is the price plan for one-time codes:

{"message_id": 1284417, "status": "S", "remarks": "Message submitted successfully", "uid": "login-8841",
  "client_costs": [{"phonenumber": "+37491234567", "cost": 0.021}]}

If status is F, nothing was sent and remarks says why: see Refusal reasons.

Check what the person typed

Compare it with the code you kept. Accept it once, then delete it.

Way 2: we make and check the code

Send the code

{"verification_id": 7731, "status": "S", "remarks": "Verification code sent successfully"}

Keep verification_id in the person's session. If status is F, nothing was sent and remarks says why.

Check what the person typed

The two field names are spelt verfication_id and verfication_code in this call, and the code is sent as a
number.

{"verfication_id": 7731, "status": "V", "remarks": "Verification Code is Verified"}

V means the code is right. F means the check failed. If a person is sure the code is right and the check
still answers F, send them a new code.

Do this in both ways

Protect the check on your side

Count wrong tries for each code and stop after a few, for example five. Then make the person ask for a new code.

Treat a code as expired after a few minutes, for example five. The check call itself sets no time limit.

Limit how often one phone number and one visitor can ask for a code. This protects your balance from people
who press "send again" in a loop.

If the SMS call answers 429, wait the seconds in Retry-After and send again. See Limits.

To learn whether the SMS arrived, see Delivery reports.

Viber is usually cheaper and faster where people use it: see One-time code by Viber.

One-time code by SMS

Way 1: you make and check the code#

Way 2: we make and check the code#

Do this in both ways#

Way 1: you make and check the code

Way 2: we make and check the code

Do this in both ways