How to detect and block SMS pumping fraud

Learn what SMS pumping is, how to detect it, and ways to protect your business from artificially inflated traffic in the future.

Content Marketing Specialist

Monika Karlović

Content Marketing Specialist

Dealing with SMS fraud is nothing new for businesses. From smishing, to SIM swapping, businesses and individuals are becoming more aware and prepared to deal with SMS scammers. 

But SMS pumping, which specifically targets businesses sending OTPs over SMS, is sometimes harder to catch. Many businesses are the target of SMS pumping fraud and have no idea. 

20 bn

fake A2P SMS messages were sent in 2023


of all A2P SMS traffic was fraudulent

$1.16 bn

spent on fake messages in 2023

Source: Mobile Europe

In this blog we will cover the basics of what SMS pumping is, what signs to look for, and how you can proactively protect your business from this kind of scam.

How does SMS pumping fraud work?

Essentially, fraudsters will choose a business that sends OTPs over SMS to its customers as their target for SMS pumping. They will begin to send fake OTP requests with a string of similar numbers to attack your business.

It will look like you are getting genuine OTP requests from users, when in reality a large portion of this traffic is illegitimate.  

In the end, you are paying for fake traffic. SMS pumping isn’t always easy to detect, and many businesses will continue to spend the majority of their budget on fraudulent traffic without noticing.  

There are five red flags to look for in your SMS traffic that can raise your suspicions about if you are a SMS pumping target.

5 ways to detect SMS traffic pumping

1. Location of the numbers asking for OTPs

You know where your customers are, so if you notice that you are starting to get OTP requests from regions or countries that you don’t normally get traffic from, this can be a sign a fraudster is attempting SMS pumping fraud. 

2. Bursts of requests

Do you notice that sometimes you get a random burst of OTP requests on the same day? This could be a sign that a fraudster is spamming you with fake OTP requests to artificially inflate your traffic, and it could look something like this example:

3. Sequential number patterns

If you notice that you get a series of OTP requests from phone numbers that are sequentially similar, this is a tell-tale sign that someone is using SMS traffic pumping to scam your business. The chance that multiple people with almost similar phone numbers are sending you OTP requests at the same time is close to none.  

4. Drop in conversion rates

You might have noticed that your conversion rates on OTPs are lower than you would expect. Fraudsters send you the requests, you graciously (but unknowingly) send them the PINs and of course, nothing comes from that interaction. Pay attention to your average conversion rate in your region, as it varies from country to country. If you notice, for example, a 20% drop in conversion rates for your SMS OTP requests, this could be a sign that SMS pumping fraud is effecting your business.

Depending on where you operate, a drop in your conversion rates could look like this:


average SMS OTP conversion rate in September


average SMS OTP conversion rate in October

5. Running out of SMS budget

SMS traffic pumping causes many businesses to quickly eat through their SMS budget because of the large number of OTP requests they send to illegitimate numbers. If you notice you are quickly running out of money in your SMS budget, it’s likely you are a target of SMS pumping fraud.  

If you have noticed any of these things occurring, it could be a sign that you are a target of SMS pumping fraud. It’s time to take control of your SMS traffic and block these fraudsters.  

Let’s walk you through the how. 

Proactively block SMS pumping

Infobip Signals is a security tool that can block and prevent SMS pumping from affecting your business.  

Think of it like this: 

In some areas, more so than others, tap water is much risker to drink. Similar to how SMS scams are more likely to occur in certain regions like APAC, MENA, Africa and CIS.  

When you fill a glass with tap water, you can’t always be sure that some questionable minerals or chemicals haven’t made it into your glass. After drinking contaminated water for some time, your suspicion might rise that something isn’t quite right, just like how many businesses pay for fraudulent traffic for a while before they notice any red flags. 

Infobip Signals acts as your water filter, cleaning your SMS traffic and blocking any SMS pumping fraud from reaching your business.  

If we notice suspicious patterns, we block those numbers from sending messages to your business. All other traffic is sent directly to your business without interruption, and the fraudulent numbers are blocked. Meaning you are not charged for that fake interaction.  

How to start using Infobip Signals?

You must be an Infobip SMS customer to start using Signals. If you are, all you have to do is request to turn on Infobip Signals like a water filter and start proactively blocking SMS traffic pumping fraud. No heavy lifting required. Talk to support today to start blocking fraudulent traffic.   

If you want to start using Signals, you can switch to Infobip as your SMS provider- but don’t worry it’s quite simple: 

With over 15 years of experience in SMS and 800+ direct operator connections, we want to help you get connected to your customers worldwide, securely. Proactively stop SMS traffic pumping and start paying for legitimate traffic only.  

Safeguard your business from SMS pumping

Get in touch with us today to learn more about Infobip Signals

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Sep 29th, 2023
5 min read
Content Marketing Specialist

Monika Karlović

Content Marketing Specialist