What the checker tells you
- Line type. One of Twilio's documented types: landline, mobile, fixedVoip, nonFixedVoip, personal, tollFree, premium, sharedCost, uan, voicemail, pager, or unknown.
- Carrier and network codes. The carrier name and the mobile country and network codes (MCC and MNC) where Twilio reports them.
- Score and grade. Set by line type alone: mobile 95, fixedVoip 45, nonFixedVoip 15, voip 15, landline 10. Toll-free and unknown are not scored. Grades run A (90 to 100) to F (0 to 29). A real carrier tops out at 95, never 100, because even a real number can be blocked if its range has a bad reputation.
- What it means in practice. Which services commonly reject VoIP numbers for verification, split into documented and reported.
The line types, in plain words
| Type | Twilio's definition | Score |
|---|---|---|
| mobile | A mobile number that generally can receive SMS messages. | 95 |
| fixedVoip | A virtual phone number associated with a physical device, for example Comcast or Vonage. | 45 |
| nonFixedVoip | A virtual phone number obtained online without requiring a physical device, for example Google Voice or Enflick. | 15 |
| landline | A landline number that generally cannot receive SMS messages. | 10 |
| tollFree | A toll-free number where calls are free for the calling party. | not scored |
| personal, premium, sharedCost, uan, voicemail, pager, unknown | Other documented types. Rare for the numbers people check here. | not scored |
Why VoIP numbers fail verification
Services like Google, banks, WhatsApp and dating apps treat VoIP numbers as high risk, because they are cheap to spin up in bulk and heavily used by bots and fraud. When you verify with a VoIP number, the service may refuse at entry, accept the code for sending but never deliver it, or let you pass once and lock you out later. A real mobile line is tied to an actual carrier and treated like any personal phone. More on what a VoIP number is.
Check numbers from code
The same check is an API. No key, no signup, open CORS. Add &format=text for a one line answer.
curl "https://numberrank.dev/api/check?number=+15551234567&format=text"There is also an OpenAPI spec, an MCP server at https://numberrank.dev/mcp for agents, and llms.txt.
One honest caveat
Line type is not a single source of truth. Different databases classify the same number differently, and even a real number can be blocked if its range has a bad reputation. numberRank reports what Twilio Lookup returns, which many services rely on, so it is a strong signal, not a guarantee. What happens to a number you check.