Industry guide

Phone intelligence for neobanks

Neobanks onboard customers remotely, settle payments instantly and authenticate everything over mobile. That makes the phone number one of the few constants across the entire customer lifecycle. Carrier lookup, number type detection, active status and SIM swap signals give fraud and compliance teams a layer of intelligence that is hard to spoof and cheap to check at every trust boundary.

Why phone signals matter more for neobanks than traditional banks

A traditional bank can fall back on branch verification, physical card issuance and legacy fraud systems built over decades. A neobank cannot. The product is a mobile app, the identity check is remote, and the account is open in minutes. That speed is the product's advantage and its attack surface.

Phone signals close gaps that document verification alone cannot. A synthetic identity built from a stolen name and a fabricated document will pass a selfie check, but the phone number behind it often tells a different story: a non-fixed VoIP number provisioned hours before the application, a number registered in a different country to the claimed address, or a SIM that was swapped the same day as a password reset.

Where phone signals fit in the neobank lifecycle

There are four moments where a phone lookup adds the most value. Each uses different signals and has a different tolerance for friction.

1. Onboarding and KYC

The highest-volume check. Every new customer submits a phone number, and that number can be queried before document verification even begins. The signals that matter here:

• Number type: is this a mobile number, a landline, or a VoIP number? Non-fixed VoIP numbers (the kind you can provision online in seconds) correlate strongly with multi-accounting, promo abuse and synthetic identity applications. Flagging them does not mean blocking them, but it means routing them to a higher-scrutiny path.
• Carrier and country: does the number's carrier and registered country match the customer's claimed location? A UK neobank seeing an application from a number registered to a German carrier is not necessarily fraud, but it is a signal worth recording.
• Active status: is the number currently reachable on the carrier network? A disconnected number on a new account is a strong risk signal. It suggests the number was used to receive an OTP and then abandoned.

These checks run before document verification, so they catch low-quality applications before you spend money on a Sumsub or Onfido call. For more on this, see adding telecom signals to your existing KYC stack.

2. Transaction monitoring and APP fraud

Under the UK's mandatory reimbursement rules, payment firms on both sides of an authorised push payment (APP) fraud case bear liability. That makes pre-transaction checks a direct cost lever.

A phone lookup before a high-value payment or transfer serves two purposes. First, it verifies that the sender's phone is still under their control: a recent SIM swap before a large transfer is the classic account takeover pattern. Second, it verifies the recipient's number: mule accounts frequently use disposable or recently activated numbers.

For the full picture on APP fraud and how telecom signals fit into the payment flow, see stopping APP fraud with phone intelligence and the UK APP fraud reimbursement rules explainer.

3. Account recovery and credential resets

Password resets and account recovery flows are the most targeted moment in a neobank's authentication chain. An attacker who controls a customer's phone number via a SIM swap can intercept the OTP sent during a reset, take over the account and initiate withdrawals.

A SIM swap check before sending a recovery OTP catches this pattern. If the SIM was recently swapped, the neobank can route the recovery through a different channel: in-app biometric, email verification or a manual identity check. The cost of one additional API call is negligible compared to the fraud loss and the regulatory scrutiny that follows an account takeover.

See screening phone number changes during account recovery for the detailed flow.

4. Ongoing monitoring and dormant account review

Regulatory obligations do not end at onboarding. Periodic checks on customer phone numbers catch numbers that have been recycled by the carrier (assigned to a new subscriber), ported to a different network, or disconnected entirely. Any of these changes on a dormant account that suddenly becomes active is worth investigating.

Regulatory context for UK and EU neobanks

Neobanks operating in the UK and EU face overlapping regulatory expectations that phone intelligence supports directly:

• FCA Consumer Duty and the Financial Crime Guide (PS24/17): the FCA expects firms to demonstrate proportionate controls. Phone signals provide evidenced, auditable risk signals that complement document checks. See the FCA PS24/17 and phone risk signals guide.
• PSD2 Strong Customer Authentication: SMS OTP is a common SCA factor, but a SIM swap collapses the independence it relies on. Checking for a recent SIM swap before sending an OTP is a proportionate control. See PSD2 SCA and the weakness of SMS OTP.
• GDPR: phone lookups for fraud prevention typically fall under legitimate interest. The key is data minimisation: querying only the signals you need, retaining only the decision outcome, and documenting the lawful basis. See GDPR-compliant telecom data for KYC.

What a phone intelligence API returns

Telebase returns the first four signals in a single API call. SIM swap detection is launching, with early access open and carrier registration completing in the target markets. For a broader look at how to evaluate providers, see the decision guide for choosing a phone intelligence API.