SIM Swap Detection API

See whether the SIM behind a number changed recently, before you trust that number as an identity or recovery factor.

Try it free Pricing and country coverage on request: pricing@provero.io

What it checks

SIM Swap Detection asks the mobile network whether the SIM associated with a number has changed recently. It matters because a phone number is widely used as an identity and recovery factor: one-time passcodes, password resets and account changes are routed to it. If control of the number moved to a different SIM shortly before someone tried to use it that way, the timing is worth knowing about. The check reports the SIM change, not the reason for it, so what you get is a timing signal to weigh, not a fraud verdict.

What it returns

Recent SIM change indicator , whether the SIM associated with the number has changed within a recent period
Timing context , how recently the change occurred, where the network makes that available, so you can judge it against the moment the number is being used

Ask us about country and network coverage and pricing: pricing@provero.io

When to use it

Before sending a one-time passcode or SMS 2FA code, where the whole security assumption is that the number is still controlled by the same person.
In account recovery and password reset flows, which are the flows SIM swap attacks are aimed at.
Before a high-value payment, payout or change of account details that has been authorised by SMS.
At onboarding, alongside Mobile Network Identity Verification, when a phone number is carrying real weight in an identity decision.
As an input to a step-up decision: allow, challenge with another factor, delay, or route for manual review.

When not to use it

As evidence of fraud. People change SIMs for entirely ordinary reasons: a lost or damaged handset, an upgrade, a move to eSIM, a switch of network. A recent change is a reason to look harder, not a reason to conclude.
As an identity check. It says nothing about who the person is. Use Mobile Network Identity Verification for identity corroboration.
As a check on whether the number works. Use HLR Phone Verification for live network and reachability.
Where coverage is not confirmed. Availability depends on the country and the network; ask us before you build against it.

How to read the result

This is a timing signal. Its meaning comes almost entirely from what the number is being used for at that moment.

No recent SIM change: Nothing here to raise concern. The number carries whatever weight your process normally gives it.
Recent SIM change: Weigh it against what is happening. Before a routine marketing message it is close to irrelevant; immediately before a password reset or a payout it is worth a step-up, a delay or a review.
No result available: The network returned nothing usable for that number. Fall back to your other signals rather than reading absence as a clean result.

Pricing

Pricing and country coverage on request: pricing@provero.io

This check is quoted on request, because the rate depends on volume and coverage. Everything else runs on the same prepaid balance. See published pricing.

Need custom pricing? pricing@provero.io

API & bulk usage

Run SIM Swap Detection as a real-time API call at the point the number is about to be trusted, which is where the timing signal is worth having. You can also combine it with other Provero checks in a single request and get every signal back in one response.

Related checks

No single check settles whether a record can be trusted. These are the ones people usually run alongside SIM Swap Detection, each answering a different question about the same record.

See every Provero check →

SIM Swap Detection FAQ

What is a SIM swap?

A SIM swap is when the SIM associated with a mobile number is changed, so calls and messages to that number reach a different SIM. It happens legitimately all the time, after a lost handset, an upgrade or a move to eSIM. It is also a known attack technique, because it redirects one-time passcodes and account recovery messages.

Does a recent SIM change mean fraud?

No, and it should not be treated that way. Most SIM changes are ordinary. The signal becomes meaningful in context: a SIM that changed hours before someone requests a password reset or a payout is worth challenging, while the same change before a routine message is not interesting.

Where does this check fit in a fraud process?

It is best placed immediately before the moment the phone number is trusted, such as an OTP, a recovery flow or a change of payment details. It is an input to a step-up decision, alongside signals like IP fraud and identity corroboration, rather than a decision on its own.

How is this different from HLR phone verification?

HLR tells you the number is a live mobile and which network serves it now. SIM Swap Detection tells you whether the SIM behind that number changed recently. One is about the number working, the other about control of it moving.

Which countries and networks are supported?

Coverage depends on the country and the operator. Email pricing@provero.io or support@provero.io for current coverage before you build against this check.

Start with this check

Create a free account, claim your credits and run SIM Swap Detection as a real-time API or a bulk upload. No card required.