Duphlux: Phone Number Verification Alternative to OTPs


Disclaimer: I’m part of the development team

Duphlux.com has just been launched and is expected to become a very reliable alternative to OTP codes normally sent to users to verify their phone numbers when trying to make payments using their cards.

It simply works by giving the app(duplux) a missed call. A number is displayed for the user and the user dials the number with the phone number. Duplux automatically ends the call once it goes through, no charges are incurred and your number is automatically verified.

You can agree with me that solves a lot of problems associated with OTP codes such as not receiving the code especially for people that have their devices on do not disturb, or the the code taking too long to deliver and possibly expiring by the time you finally enter the code.

The application is subscribed free for the first month after which a very little amount is charged for further use. Developers here would definitely want to check this out and send your feedbacks(highly appreciated).

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Re: Duphlux Phone Number Verification Alternative to OTPs - SDKs Now Available

Nice concept. Link?




The link is duphlux.com


And what happens where the user doesn’t have airtime to place the missed call?


That is a typical call back scenario and its forbidden in many countries. The local operator do not benefit from such system. Its a way of bypassing charges from local techo. There are known issues where vendors block such numbers from been called in its totality…I would vouch for the OTP instead…given this local techo got no issue with your app or verification system…
If you are an app owner or payment gateway wanting to verify users and in full production without fear of favor of local blockage, please run from this callback idea…


Okay, correct me if I’m wrong, I see two points
In the issue of being forbidden, from my research, I haven’t found any facts backing the claim.

On the issue of the operators not making money, you can agree with me that you will not be able to make a call without having airtime and someone who is serious to verify will get airtime. Now that’s the telco making money

@Dapo all solutions have challenges including OTPs and we are aware of your concerns and are already working on it. The plan is to get toll free numbers to eliminate this challenge. @crescent you can also agree with me that toll free numbers come at a cost and that’s the operator making money too.


Callback is a Communications fraud. Your argument is baseless. Google back services to understand how local telco are been bypassed and used without benefit. Its both financial and technical stress to major telco… That missed call was never terminated in any way and not paid for… Its reaping where you did not sow. If that callback continue to hit their system, sorry such number that is triggering that call back can be blocked. Even if anyone still proceed to use to verify users, there are instance that caller ID can be shown as “unknown” private, or even “call” leaving the new user sign up or even a client to abandon the process. Its a system to be avoided…


I think the Fonenode IVR service is a preferred option:

The One Time Password (OTP) resource helps you quickly authenticate users on your platform with their mobile numbers. The user receives a call immediately bearing his code as the caller id, when the user picks, the call is hungup.

You should store the response from calling this API, as the code in the response is the same number that calls the user.

  1. Create An OTP

Create a 5 digit OTP code and fires a call (a flash actually) to the desired number.

URL: https://api.fonenode.com/v1/otp

Method: POST


to: Number to make an OTP call to. Must be in International format. E.g 234811056859

code (Optional): 5-6 digit code to use as OTP code, if not supplied, a default 5 digit code will be auto generated. E.g 12345



According to your claim, it suffices to say you have been ripping off your service provider each time you flashed a number and I am most certain you must have flashed someone at one time or the other.

If there are real bases for your argument, I’d ask that you give me a precise reference to your argument

You may want to checkout this article on communications fraud COMMUNICATIONS FRAUD

I also believe you read what i wrote as regards acquiring toll free numbers.


Flash, missed, callback, sms a number with the intention of getting an auto callback for the purpose of bypassing a fee on terminated call = Telecoms FRAUD… Most telco dont joke with this and I fully support its avoidance.


It works, which is nice. Tip: turn the phone number displayed into a <a href="tel:+1xxxxx"> so I can just click on it to open the dialer


Okay. That’s a great suggestion. Thanks.


I entered a phone number with leading + e.g +2348123456789 and it called ++2348123456789 and did not go through… Do some input checking to remove any leading + if entered before calling.


Ok. Thanks @Victorybiz for the Observation. the additional + won’t affect the expected result but we’ll fixed the glitch.


You cannot tell people to outrightly avoid a solution to a problem without backing your claim. Provide a reference to a document that can help us understand. Can you do this?


@ncodes exactly. In my opinion, i Feel @crescent may have subjective reasons for bluntly insisting no one uses the solution. More importantly I appreciate your objectivity and rationlity


Going by your arguement, then any VOIP service is fraud because it was done to avoid the fees of regular phone calls… i.e. FaceTime, whatsapp call, Facebook call etc are all fraudulent.

Also, funds transfer using services like transfer wise , western union etc are all fraudulent because people sometimes use them to avoid bank transfer fees.

My point is , it’s not enough to say because u avoid a fee you are committing fraud. It’s true that the telcos will lose revenue, but am sure the OP can use an international number which the local telcos will easily have access to. Furthermore , if one number is blocked another number can easily be provided. The OP can buy 100 US numbers for just $100.


@easibor on point!!


@easibor How is VOIP structured to be a fraud? You lack proper education. whatsapp, or VOIP in general requires a data plan or wifi (paid) offered by telco to function.
VOIP can be classified as ripping off revenue from a licensed telco, but they the telcos are also seen in offering voip as well which compliments one another… In both ways they profit. If you can not beat them you join them… its a win-win affair.
Telco offers VOIP as well if you are not vast in knowledge to understand how voip works.
Telco gets a continuous income from your use of paid data… To further put you on the know… Telco can block VOIP as well if they feel is a killer of revenue, ie UAE, Egypt etc are clear examples.
Voip is not a fraud but a technology to save on long distance calls which both parties benefit from.
Callback is a calculated fraudulent attempt to steal at the interest of the perpetrators. In Nigeria NCC forbids the use of any ACCESS number as Callback in handling a calling card for example few years ago when some unregistered invisible local champions tried offering long distance callback services, which allows you to call a dedicated number and hang up at a ring, and using a caller ID algorithm, the system sees your caller id and calls you back to make your international calls while completely eliminating local telco who pays taxes… I will rest my case…