Fraud and KYC

Number type detection for fraud

Telebase tells you whether a phone number is mobile, landline or VoIP, along with its carrier, country and active status, from a single per-query API call. VoIP and inactive numbers correlate strongly with fraud at onboarding, so screening number type lets you flag higher-risk signups before they reach a human reviewer. Pricing is $0.03 per query with no contract and no minimum spend.

Why number type matters at onboarding

Fraud rings favour numbers that are cheap, disposable and hard to trace. VoIP numbers fit that profile: they can be provisioned in bulk, require no SIM card, and are straightforward to abandon. A sudden spike in VoIP signups, or a VoIP number on an account claiming to be a long-standing mobile user, is a useful early signal worth reviewing.

Number type sits alongside your other checks rather than replacing them, but it is fast, cheap and easy to act on at scale.

Number types Telebase returns

• mobile: a SIM-based mobile number, the expected type for consumer onboarding
• landline: a fixed-line number; worth flagging in mobile-first onboarding flows
• fixedVoip: VoIP assigned to a fixed address, lower risk than non-fixed
• nonFixedVoip: VoIP with no fixed address, the highest-risk number type for fraud screening
• tollFree: toll-free number; unusual at consumer onboarding
• voicemail: voicemail-only number, cannot receive live calls or SMS

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"  // launching
}

Coverage

Number type, carrier, country 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. The leading + must be URL-encoded as %2B in the query string.