VoIP Numbers in Lead Lists: Keep Them, Drop Them, or Treat Them Differently?
Don't drop VoIP numbers from a lead list by default. In B2B lists they're often real desk lines on a company's phone system; in consumer lists they're more often secondary or throwaway numbers. Segment them: find VoIP numbers with a carrier lookup (US and Canada) or the numbering plan (elsewhere), keep business VoIP lines in your call lists, treat free consumer VoIP numbers as lower-intent, and test before including any VoIP numbers in an SMS campaign.
What counts as a VoIP number
VoIP (voice over IP) numbers carry calls over the internet instead of a traditional phone line or a mobile network. In lead lists they fall into rough groups:
| Type | Examples | What it usually means in a lead list |
|---|---|---|
| Business phone systems | Desk lines on a cloud PBX or a UCaaS platform | A real direct line or a company number |
| Fixed home VoIP | Home phone service from a cable or broadband provider | A household landline in practice |
| Non-fixed consumer VoIP | Free or cheap app-based numbers | Often a secondary number; can be a throwaway |
| Virtual numbers for SMS | Numbers rented for verification codes | Low-intent at best |
"Fixed" VoIP is tied to a service address; "non-fixed" can be used from anywhere. Carrier lookups report VoIP as a line type; some providers distinguish fixed from non-fixed and some don't. More background: how to check if a number is VoIP and phone line types explained.
Why VoIP numbers turn up in your list
- B2B data. Many companies run their phones on VoIP systems, so a direct dial from a data provider can come back as VoIP. That's not a quality problem; it's how the company's phones work.
- Consumer forms. Someone who wants a quote but not a sales call gives a secondary number they can ignore.
- Fraud and abuse. Disposable virtual numbers are used to pass SMS verification on signups. If you see many of them on a trial or promotion form, that's a signal.
Should you keep them? It depends on the channel
For calling
Keep business VoIP lines. They ring on a desk phone or a softphone like any other work number. For consumer leads, keep them but expect lower answer rates on free app-based numbers, and track it: if a source's VoIP numbers never pick up, that's useful data about the source.
For SMS
Many VoIP services can send and receive texts, but not all. Some business VoIP numbers aren't text-enabled at all, and messages to them fail. Before a campaign:
- Separate VoIP numbers into their own segment.
- Send to a small sample and look at delivery reports. On Twilio, codes like 30006 ("Landline or unreachable carrier") and 30003 ("Unreachable destination handset") tell you which ones can't receive. See Twilio SMS error codes.
- Keep the VoIP numbers that delivered, drop the ones that didn't.
Consent rules for texting don't change because the number is VoIP. In the US, treat automated texts to any number as needing prior consent, and see TCPA: mobile vs landline. This isn't legal advice.
For verification and security
If a phone number is used for account security or to prevent duplicate trials, non-fixed VoIP numbers are weaker evidence of a unique person, because they're easy to get. Many teams accept them but don't treat them as proof of identity. See SaaS trial signups: verify emails and phones.
How to find VoIP numbers in a list
US and Canada: carrier lookup
North American numbers don't reveal their line type from the digits: mobile, landline and VoIP numbers share area codes, and numbers port between them. A live carrier lookup asks the network who serves the number now and returns the carrier and its line type: mobile, landline or VoIP. Try one in the free landline or mobile checker.
Elsewhere: often the numbering plan
Some countries give VoIP or "nomadic" services their own number ranges, so a numbering-plan check labels them without a lookup. Others allow VoIP on ordinary geographic numbers. The format check on SimpleVerifier returns the numbering-plan type where the country's plan defines one.
The workflow
- Export the list to CSV with phone numbers as text.
- Upload to the verify page or the bulk phone number validator. Numbers that can't exist are marked invalid; the rest get E.164, country and numbering-plan type.
- Remove fakes with the fake phone number checker: placeholders, repeated digits and fictional ranges show up next to VoIP numbers in low-intent sources.
- Run carrier lookups on the US and Canadian numbers you plan to text or prioritise.
- Segment:
mobile,landline,voip,invalid. The phone list segmenter helps split the file. - Dedupe on the E.164 number with remove duplicate phone numbers.
A simple policy
| Source | VoIP number | Action |
|---|---|---|
| B2B data provider, direct dial | Business VoIP | Keep for calls; test before SMS |
| Inbound demo request | Any VoIP | Keep; call as normal |
| Consumer quote form | Non-fixed VoIP | Keep, lower priority; prefer email first |
| Promotion or trial signup | Many non-fixed VoIP | Review for abuse |
| SMS campaign list | Any VoIP | Separate segment, sample first |
Verify the emails while you're there
A lead list with a VoIP number and a valid email is still a reachable lead. If the CSV has an email column, the same upload runs a live SMTP mailbox check on each address, and catch-all addresses come back as risky, never guessed valid (catch-all grading). See verify emails and phone numbers together.
What it costs
- Free: 100 checks with a Google sign-in, no card.
- Pro, $39 a month: phone format checks on every row (status, E.164, country, numbering-plan type), Unlimited email verification*, the API and the MCP server.
- Pro + Phone, $49.99 a month: adds 5,000 live carrier lookups a month with carrier and carrier-reported line type, US numbers included.
- Starter, $9 a month: 2,500 emails a month, email only.
*Fair use: the first 100,000 checks a month at full speed, then slower, never cut off. Phone lookups and API calls are not part of Unlimited.
See pricing.
More reading: phone carrier lookup, phone number validation for cold calling, can you text a landline.
Common questions
Are VoIP numbers bad leads?
Not as a rule. In B2B, many direct lines are VoIP because the company's phone system is. In consumer forms, a free VoIP number is more often a secondary number someone gives to avoid sharing their mobile. Segment by source and line type rather than deleting.
Can you send SMS to a VoIP number?
Sometimes. Many VoIP services, including popular consumer ones, can send and receive texts. Some business VoIP numbers aren't text-enabled. Your SMS platform will report failures for the ones that can't receive.
How do I find VoIP numbers in a list?
For US and Canadian numbers, use a live carrier lookup, which returns the carrier-reported line type: mobile, landline or VoIP. In some other countries the numbering plan sets aside VoIP ranges, so a format check identifies them.
What is the difference between fixed and non-fixed VoIP?
A fixed VoIP number is tied to a physical address, like a business phone system or a cable provider's home phone. A non-fixed VoIP number can be used from anywhere with an internet connection and is often available free or for a small fee.
Check your list before you send
Real mailbox checks over SMTP, and nothing is sent to the address. Sign in with Google and your first 100 email checks are free, no card. Plans for bigger lists are on the pricing page.