Know who'sworth callingbefore you dial
Find out which numbers are real, which are a litigation risk, and which people are actually worth calling first - before your team picks up the phone.
The problem
Bad phone data wastes good dials.
Every disconnected, reassigned or mistyped number costs a caller another attempt that was never going to connect. The list looks full. The dialling day says otherwise.
Data ≠reality
A number in the CRM is not a number that works
It was accurate when somebody typed it in. Nothing about sitting in a database keeps it that way.
The wasted dial
The dial is the only test most teams run
Which means the discovery that a number is dead costs a caller their time rather than a lookup.
Bad data travels
Bad records spread
Exported, enriched, merged and re-imported, an unusable number travels through every system it touches.
Why it happens
Phone data doesn't stay accurate forever.
Nothing you do to a spreadsheet keeps the lines behind it connected. Three things quietly break a list between the day it was built and the day it is called.
Numbers get disconnected
People change jobs and providers. A number that worked last quarter may be disconnected today, while the record in your CRM stays the same.
Line types and carriers change
Numbers get ported between networks and move between mobile and fixed. The number you hold stays the same while the carrier behind it changes.
Lists go stale across sources
A record assembled from a provider, a form fill and a CRM export inherits the age of all three. The oldest part decides how good it is.
Your stored record
+1 212 555 0184
- JanActiveCarrier A
Record added to your CRM.
- AprPortedCarrier B
Number ported to a new network.
Your CRM record unchanged.
- AugDisconnectedNo carrier
Number now disconnected.
Your CRM record unchanged.
Reality changed.
Your stored record didn't.
Outdated data leads to wasted dials, lower connect rates and lost opportunities.
The solution
Run every check from one place.
Check whether a number is real, rank a contact by how likely they are to answer, or do both at once - from the checker, a CSV, the API or an AI agent.
Here is what a number check turns one number into.
Before the check
Phone number
+1 212 555 0184
- Validity
- Unknown
- Line type
- Unknown
- Carrier
- Unknown
- Country
- Unknown
After the check
Valid
- Line type
- Mobile
- Carrier
- Verizon
- Country
- United States
- International format
- +1 212 555 0184
Works the same whether you check through:
Checker
One number
CSV
Upload a list
REST API
Your stack
MCP
AI agents
Coverage
Built for phone data at global scale.
Numbers in full international format are read as they are. Numbers in a local format are checked against a country you choose, so a list from several markets needs no normalising first. Number checks reach every market below; answerability ranking covers the US.
- 200+
- Countries & territories
- 18,000+
- Carriers covered
- 1B+
- Numbers tracked
API & MCP
Use The Cold Calling Toolbox from your stack or AI agent.
The same checks, API key and credit balance across REST and MCP.
Validate a phone number from your app or backend.
Request
curl -X POST https://app.coldcallingtoolbox.com/api/v1/validation \-H "Authorization: Bearer YOUR_API_KEY" \-H "Content-Type: application/json" \-d '{"phone_number":"+12125550184"}'Response
200 OK{"exists": true,"number": "+12125550184","line": {"type": "mobile","network": "Verizon","prepaid": null},"region": {"name": "United States","code": "US","dialing_code": "1"}}Start checking in minutes.
One API key for REST and MCP.
Pricing
Pay only forwhat you check.
No subscription. Credits never expire.
The more credits you buy, the less every check costs.
1,000 credits
$50
$0.05 per validation
10,000 credits
$400
$0.04 per validation
100,000 credits
$3,000
$0.03 per validationBest rate
- 1 credit = 1 Number Check
- 5 credits = 1 Contact Intelligence
- Litigation screening always included
- One balance across CSV, API & MCP
Questions, answered.
Everything you need to know before checking your first list.
A Number Check costs 1 credit - that covers whether the number is real, what kind of line it is, and whether it carries litigation risk. Contact Intelligence costs 5, because it adds a second lookup that ranks the person by how likely they are to answer. Credits are a single balance you spend across all of them, whichever way you send the work. In a CSV, blank cells are skipped and a repeated row is only counted once, so you are charged for unique rows rather than for the file.
Check one contact from the checker, upload a CSV to do a whole list at once, call the REST API from your own code, or connect an MCP-compatible AI agent. All four spend the same credits from one balance. The checker on this page also includes one free Number Check with no account.
Yes, in every Number Check, at no extra cost. It flags numbers tied to TCPA or similar consumer-regulation litigation, as either a plaintiff or one of the attorneys. There is nothing to switch on and nothing separate to buy: it rides on the same lookup the Number Check already makes, so every number you check is screened. Where we could not get an answer the field is left empty rather than marked clean.
Yes. Upload a CSV up to 5 MB, choose which check to run, and tell us which columns hold the phone number - and the names too, if you are ranking contacts. You see the exact number of rows and the exact credit total before anything runs. A single file can hold up to 10,000 billable rows.
Number Checks cover more than 200 countries and territories. Numbers written in full international format are read as they are; numbers in a local format can be checked against a country you choose. Answerability ranking covers US numbers only - Contact Intelligence on a number from anywhere else still returns the Number Check, and says plainly that the ranking half is outside our coverage.
A Number Check tells you whether the number is valid, the line type, the carrier it was allocated to, whether it carries litigation risk, and country details including the country code and dialling code - 10 new columns on a bulk file. Contact Intelligence adds a rank from A1 to A3 or X, a recommendation, whether the number is usable, what kind of phone it is, and one plain sentence describing the signals behind the rank.
No, and that is why there are two checks rather than one. A number check tells you whether a phone number is real and in use. Whether the person behind it is worth calling first is a different question, and the answerability check is what answers it - from the name as well as the number, because who a number belongs to is half of what decides the answer.
Yes, both are live. The REST API has one endpoint per check and handles one contact per request. The MCP endpoint gives a compatible AI agent the same three checks as tools - check_number, check_answerability and check_contact_intelligence. Both authenticate with one API key you create in your account, and both spend the same credits.
Stop dialling a list you haven't checked.
Check the numbers, rank the people, and work the list in order.