Free Twilio Lookup line type intelligence, no API key
If you only need to know whether a number is VoIP or a real carrier line, you do not need an account anywhere. numberRank runs Twilio Lookup's line type intelligence field on every request and returns the result as JSON or plain text, free, with no key, no card and open CORS.
curl "https://numberrank.dev/api/check?number=+15551234567"{
"number": "+15551234567",
"type": "nonFixedVoip",
"carrier": "Twilio - SMS/MMS-SVR",
"mcc": "311", "mnc": "950",
"score": 15, "grade": "F",
"verdict": { "pass": false, "label": "VoIP", "note": "VoIP numbers are rejected by most OTP and fraud systems." }
}How it compares
Checked against each provider's own page on 2026-09-16. Prices and tiers change; the links are the source of truth.
| Option | Line type | Cost to start | Auth | Notes |
|---|---|---|---|---|
| numberRank | Twilio line type intelligence on every request | Free | None | Open CORS, about 20 checks per minute per IP, results cached 30 days. Plain text mode for agents. |
| Twilio Lookup v2 | Yes, the same field | Billed per lookup on your account | Account SID and token | The source. Use it directly when you need volume, other Lookup fields, or your own data residency. Canadian numbers need approval. |
| Abstract phone validation | Yes, its own classification | 100 requests per month free, then a paid plan | API key | Its classification differs from Twilio's. Onvoy ranges that Twilio reads as mobile can read as VoIP here. |
| API Ninjas validate phone | Yes | Free tier, non-commercial use only | API key | Commercial use is not permitted on the free tier per its FAQ. |
When to use which
- Trying something, building an agent, checking a handful of numbers: numberRank. Nothing to sign up for.
- Production volume, or you need caller name, SIM swap, or other Lookup packages: call Twilio directly.
- You want a second opinion: databases disagree on the same number. Run it through two and treat disagreement as a signal.
Also for agents
The same check is an OpenAPI spec, an MCP server at https://numberrank.dev/mcp with a check_number tool, and a llms.txt that describes the endpoint in a few lines. Add &format=text to get one readable line back.
What we do with your number
It goes to Twilio for the lookup, the result is cached for 30 days, and nothing is sold or shared. Privacy.