Validate WhatsApp
Give it a phone number, find out whether that number is registered on WhatsApp.
- Tool
validate_whatsapp- Cost
- 1 credit
- Category
- Person Enrichment
- Required input
mobile- Returns
- Whether the number is on WhatsApp
What it does
- Checks whether a phone number is registered on WhatsApp.
- Takes one input:
mobile, with the country code —"+14155552671". - Charged per check, whether the answer is yes or no.
It validates a number you already have. To find the number first, use find_mobile_number.
Parameters
| Parameter | Type | Required | Notes |
|---|---|---|---|
mobile | string | Yes | Include the country code, e.g. "+14155552671" |
How to use it
Connect the MCP server
Follow the setup guide for your client. Browser sign-in, no API key.
Check one number
Is +14155552671 on WhatsApp?Check a list
Check which of these 40 numbers are on WhatsApp. Every number already has a
country code. Return two lists: on WhatsApp, and not.Chain it after a mobile lookup
Find the mobile number for linkedin.com/in/janedoe, then tell me whether it's
registered on WhatsApp.Example prompts
| Ask your client | What you get back |
|---|---|
| ”Is +14155552671 on WhatsApp?” | Yes or no, for one number |
| ”Split these numbers into WhatsApp and not” | Two lists you can act on |
| ”Find her mobile then check WhatsApp” | Chains find_mobile_number first |
| ”Add the country code to these numbers before checking” | A cleaned list, then the checks |
Best prompting practices
- Always include the country code.
+14155552671, not4155552671. The tool expects the full international format. - Normalise the list first. Ask your client to fix formatting before it starts spending credits, not row by row as it goes.
- Only check mobiles. The parameter is
mobilefor a reason — running office lines through it burns credits on numbers that were never going to be registered. - Ask for a split. “On WhatsApp / not on WhatsApp” is directly usable; a per-row narrative is not.
- Cap the batch. “Stop after 40 and report credits used” keeps a long list predictable.
Output
{
"mobile": "+14155552671",
"registered": true
}Credits and limits
1 credit per number checked. Run check_credits (free) before a large batch.
A number without its country code cannot be matched, and the attempt still
costs a credit. Normalise every number to international format — country code
first, as in +14155552671 — before you send the batch.
Related tools
| Tool | Use it instead when |
|---|---|
find_mobile_number | You do not have the number yet — 12 credits |
find_work_phone | You want the office line — 12 credits |
scrape_phones_from_website | You need numbers published on a company site — 0.5 credits |
verify_email | You want the same reachability check for an email — 0.3 credits |
Next steps
- All MCP tools — the full catalogue with credit costs
- AI for Sales Reps — workflows that chain this tool into a list build
Keep learning
Two courses take these tools past the reference page — clustered by GTM job, then chained into workflows.
SyncGTM MCP Mini CourseBeginnerMCP server · 8 lessons · 1h 31mAll 50 MCP tools clustered by GTM job — lead sourcing, CRM enrichment, social signals, account research, scraping — with copy-paste workflow prompts.AI-Powered GTMIntermediateApp + MCP · 19 lessons · 3h 6mWhere AI earns its cost, how to think in MCP tool chains, and three agentic builds — warm outbound, meeting research, CRM repair.