FREE Phone Number Lookup
Instant Caller ID, trust ratings, and spam detection from any phone number search
The world's most advanced Caller ID & CNAM lookup tool. AI Driven, Community Supported
Instant Lookup
Get immediate results with caller ID, location, and carrier information.
Spam Detection
Community-powered spam reports help you avoid unwanted calls.
Location Data
View geographic information and carrier details for any number.
Trusted by Millions
See what our users have to say about SIPSTACK WHOIS
"Finally identified that persistent spam caller! This tool saved me from multiple scam attempts. The community reports are incredibly helpful."
"As someone who receives hundreds of calls daily, this is a game changer. Instant caller verification helps me prioritize important calls."
"Helped my elderly parents avoid several phone scams. The trust scores and community feedback make it easy to spot fraudulent callers."
Stay Protected
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Frequently Asked Questions
How does the phone number lookup work?
Simply enter any 10 or 11 digit phone number into the search box. Our system will instantly retrieve caller ID information, location data, carrier details, and community spam reports to help you identify who's calling.
Is this service really free?
Yes! SIPSTACK WHOIS is completely free to use. You can lookup as many phone numbers as you need without any charges or subscription fees. We're supported by SIPSTACK's VoIP infrastructure services.
How accurate is the spam detection?
Our spam detection is powered by community reports and AI analysis. The more reports we receive about a number, the more accurate the spam rating becomes. We analyze millions of data points to provide reliable trust ratings.
Can I report spam numbers?
Absolutely! Community participation is essential for keeping our database accurate. After looking up a number, you can rate it and leave a review to help others identify spam callers.
What countries are supported?
We currently support phone number lookups in the United States and Canada. Our database includes carrier information, location data, and spam reports for numbers across both countries.
Do I need to create an account?
No account is required for basic phone number lookups. However, creating a free account allows you to save your search history, manage your own phone number profiles, and contribute reviews to help the community.