Pair 1 · Blue
Line intelligence
Whether the number is real, live, and worth dialling.
- Valid number
- Connected or disconnected
- Line type — wireless, landline, VoIP, toll-free
- Carrier name
- Prepaid indicator
United States · Full NANP coverage
Reverse Phone Lookup API
Send one US phone number. Get back the line, the carrier, the spam score, the person behind it, where they live, how to reach them, and where they are online — 30 data points in a single request.
We are the only reverse phone lookup API that returns social media profiles, and no one returns more on a US number. The same data that has powered NumLookup.com for millions of US consumers, now available to enterprise teams under contract.
Enterprise access · minimum annual commitment applies
Sample record · illustrative
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What comes back
One number. Six layers of data.
Most phone APIs stop at "wireless," "AT&T" and barely an accurate name. Ours keeps going — past the spam score, to the person, to the address, to the inbox, and out to every profile they have online. Grouped here the way telephone cable is: by pair color.
Typical phone validation API
5 data points
NumLookup Reverse Phone Lookup API
30 data points
Every field listed below, from a single US phone number — including social profiles no one else returns.
Pair 2 · Orange
Spam score
How likely this number is to be flagged as spam before you ever dial it.
- Spam score, 0 to 100
- Risk level — low, medium, high
Pair 3 · Green
Owner information
Who the number actually belongs to.
- Full name
- First, middle and last name
- Aliases and former names
- Gender
- Age range
- Year of birth
- Associated business name
- Consumer or business classification
Pair 4 · Brown
Address
Where they are now, and where they were.
- Current street address
- City, state, ZIP+4
- County
- Previous addresses
- First and last seen dates
- Address type — residential or commercial
Pair 5 · Slate
Only on NumLookupDigital footprint
Every profile the person has online. No other phone API returns this.
- Primary email address
- Additional known emails
- LinkedIn profile
- Facebook profile
- Instagram profile
- X / Twitter profile
Pair 6 · Red
Rare in this categoryRelatives
The people connected to the person behind the number.
- Known relatives and associates
- Full name of each relative
- Age of each relative
Coverage
Every US number
Full NANP coverage. Not just the easy ones.
- Mobile numbers on all major carriers
- MVNOs and resellers
- Landlines
- VoIP and virtual numbers
- Numbers across all 50 states and DC
- Toll-free and business lines
Who this is for
Built for teams that live and die by phone data.
If a phone number is the first thing you learn about someone, this is the call that tells you the rest.
Fraud and risk
Check that the number on a signup is a real, connected line — and that the name attached to it matches the account being opened.
Lead enrichment
Turn a bare phone number from a form fill or list purchase into a named contact with an email, an address and a LinkedIn profile.
Identity verification
Match a customer's phone number to their name and address during onboarding, without asking them for another document.
Contact centers
Screen-pop the caller's name and history before your agent says hello. Route business lines differently from mobiles.
Contact quality
Screen each number the moment it enters your CRM. Disconnected lines and high spam-score numbers get flagged on the way in, not after a campaign underperforms.
Debt recovery and legal
Confirm a current line and current address for a file that went cold, and work outward through known relatives when the trail on the subject runs out.
Why NumLookup
Nobody returns more on a US phone number.
Unmatched breadth on every field, and unmatched coverage across every US carrier — including the MVNOs and VoIP providers that thin out other vendors’ match rates. And social media profiles that no competitor returns at all.
Proven before it was an API
This dataset has been answering reverse phone lookups for millions of US consumers on NumLookup.com. It was hardened by real people searching real numbers long before it had an endpoint.
One call, not five
Carrier lookup from one vendor, identity from another, email append from a third — that's three contracts and three latencies. Here it's one request and one bill.
Built for volume
Contracted enterprise pricing with a minimum annual commitment, and a rate per lookup that drops as your volume climbs. Sized around your forecast, not a public price list.
Responsible use
Powerful data comes with rules. We take them seriously.
Access is reviewed before it's granted. We ask what you're building and we turn down use cases that don't hold up — because the alternative puts every customer on the platform at risk.
This API is not a consumer report and is not intended for eligibility decisions covered by the Fair Credit Reporting Act — including employment screening, tenant screening, credit and insurance underwriting. Customers agree to those limits in writing before their key is issued.
Questions
Reverse phone lookup API, answered.
What is a reverse phone lookup API?
It's a service your software can call with a phone number to get back everything known about that number and the person or business behind it. Instead of a person typing a number into a website, your application asks the question automatically, in real time, wherever a phone number enters your product.
What data does the NumLookup API return for a phone number?
Line validity and connection status, line type, carrier, a spam score with a risk level, the owner's full name, aliases, gender and age range, known relatives with their names and ages, current and previous addresses, email addresses, and social media profiles — the last of which no other reverse phone lookup API returns. Coverage of each field varies by number — every result tells you what was found and what wasn't.
Does it work for mobile numbers, VoIP and landlines?
Yes. Mobile numbers on every major US carrier and MVNO, landlines, VoIP and virtual numbers, and toll-free business lines are all supported. Coverage is United States only.
How current is the data?
Carrier and line-status data is queried against live sources at request time, so a number that was disconnected yesterday reports as disconnected today. Identity and address data is refreshed on a continuous cycle from a large set of contributing sources.
Can I use it for employment or tenant screening?
No. This is not a consumer reporting agency product and cannot be used for decisions covered by the Fair Credit Reporting Act — that includes employment, tenancy, credit and insurance eligibility. If that's your use case, we'll tell you upfront rather than sell you something you can't legally use.
Is this a real-time API?
Yes. Every lookup is a live request answered in a fraction of a second, so you can call it inline during a signup, a lead submission or an inbound call without holding up the user. Tell us your monthly volume in the form below and we'll size a plan around it.
What does it cost?
Pricing is contracted per lookup and scales down as volume rises. Access requires a minimum annual spend commitment, so this is built for teams running sustained lookup volume rather than occasional queries. Send us your forecast and we'll come back with a number.
How do I get started?
Fill in the form below. We'll review the use case, answer any questions, and send credentials and documentation once you're approved. Most requests get a response within one business day.
Get access
Tell us what you're building.
Fill this in and a real person reads it. We'll come back with contracted pricing for your volume, sample results for numbers you care about, and credentials once you're approved.
- Response within one business day
- Test lookups on your own numbers before you commit
- Dedicated account and integration support
- Contracted pricing sized to your forecast volume
Request received
Thanks — your request for API access is in. A real person reads every one, and we'll reply within one business day with pricing and next steps.
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