SIM swap check: catch fresh SIM changes before you approve anything risky.
When someone moves a phone number to a new SIM, texts and calls for that number can land in the wrong hands. Ask before you approve, and step up checks only when it matters.
- Spot a recent SIM change
- Step up only when needed
- One check from your own app
Why a fresh SIM change is worth a second look
In a SIM swap scam, a fraudster gets a victim's number moved to a SIM they control. Codes sent by text then go to the fraudster. A quick check tells you when to slow down.
- 01
Number moved to a new SIM
The real owner's phone loses signal.
- 02
Fraudster tries to get in
They ask for a password reset or a login code.
- 03
The code goes to their SIM
A text code on its own proves nothing now.
- 04
You check before approving
A fresh SIM change means: ask for more.
Ask one question before you approve
Has this number just changed SIM? Run the check at the moment that matters, then let your app choose. Most customers sail through, and the risky ones get the extra step.
Illustrative customers, numbers and amounts
One request, one clear answer
Send the phone number and your app gets back whether a recent SIM change was seen, so it can decide in a single step. Use the answer in your own rules, or pair it with Verify and OTP.
Your app sends the number and gets one answer back.
Illustrative numbers and answer
Run the check wherever a stolen number would do harm
Use it on the actions a fraudster wants most, and leave everything else smooth.
Money transfers
Check before a new payee or a large transfer goes through.
Account recovery
Check before you reset a password or change an email address.
New device sign in
Check before you trust a login from a device you have not seen.
High-value orders
Check before you release goods or credit to a new buyer.
Give your customers SIM swap checks under your own brand
Launch the check inside your own console under your own logo and domain. Your customers add it to their apps, and every answer carries your name.
Change the name, domain and colour once, and every screen your customers see follows.
The questions teams ask on the first call.
What is a SIM swap?expand_more
A SIM swap is when a phone number is moved to a different SIM card. It is a normal thing to do when you change phones, but fraudsters use it to take over someone's number and receive their texts and calls.
What does a SIM swap check do?expand_more
A SIM swap check tells you whether a phone number has had a fresh SIM change, so you can ask for extra proof before you approve something risky.
When should I run a SIM swap check?expand_more
Run it at moments a fraudster would aim for: new payees and large transfers, password and email changes, sign ins from new devices and high-value orders. You can leave low-risk steps alone.
Does a recent SIM change always mean fraud?expand_more
No. People change phones all the time. A recent SIM change is a signal to ask for more proof, not a reason to refuse. That is why the check works best alongside a step-up step.
Can I use it with one-time codes?expand_more
Yes. A SIM swap check pairs well with Verify and OTP: check first, then send a code only when the number looks safe, or ask for another proof when it does not.
Can I offer SIM swap checks under my own brand?expand_more
Yes. Partners launch the Comms APIs under their own logo and domain, so your customers use SIM swap checks that carry your name.
Ready to add a SIM swap check?
Talk to our team about SIM swap checks in the Comms APIs, under your own brand.