KYC and Compliance

Phone number validation API for KYC

Telebase validates a phone number at KYC by returning its carrier, country, number type (mobile, landline or VoIP) and active status from a single API call. An inactive number, a VoIP number, or a number registered in a country that does not match the customer's stated address is a risk signal worth reviewing before completing onboarding. Pricing is $0.03 per query with no contract and no minimum spend.

Why phone number validation matters at KYC

A phone number submitted at onboarding should be active, consistent with the customer's claimed country, and on a carrier type that fits the customer profile. When it is not, the mismatch is worth noting. Inactive numbers may indicate abandoned accounts being recycled by fraudsters. VoIP numbers are cheaper and more disposable than mobile numbers, making them a higher-risk signal in consumer onboarding flows. A number registered in a different country from the application adds friction to identity verification.

Checking these signals at the point of onboarding is fast, inexpensive and requires no action from the customer. It is not a replacement for document checks or database screening, but it is a useful addition to the first-pass risk layer before a file reaches a human reviewer.

What to flag

• Inactive numbers: the number is not currently live on the network
• VoIP numbers: cheaper and more disposable than mobile numbers, with a higher correlation to synthetic accounts
• Country mismatches: the number is registered in a country that does not match the customer's stated location
• Carrier anomalies: a consumer account served by a wholesale or foreign MVNO is worth a second look

What Telebase returns

• carrier: the network operator serving the number
• country: the country where the number is registered
• numberType: mobile, landline, fixedVoip, nonFixedVoip, tollFree, or voicemail
• active: whether the number is currently reachable on the network

Example call

GET https://telebase.fatcatremote.com/api/lookup?phone=%2B447700900000
Authorization: Bearer tb_live_xxxxxxxxxxxxxxxxxxxxxxxxxxxx

{
  "phoneNumber": "+447700900000",
  "active": true,
  "carrier": "EE",
  "country": "GB",
  "numberType": "mobile",
  "simSwap": "UNKNOWN"
}

Coverage

Carrier, country, number type and active status are live across GB, NL, DE and FR. Numbers must be passed in E.164 format, for example +447700900000 for a UK number or +31612345678 for a Dutch number.