The Facebook e-mail check answers whether an e-mail address is associated with a Facebook account. It runs in real time and in bulk jobs, and returns registered: true, false or null (unknown), with the time we checked. Nothing is sent to the address, and no name, photo or profile is ever returned.
What does the Facebook e-mail check tell you?
It tells you whether Facebook has an account that uses this e-mail address, either for sign-in or as a contact address. Facebook lets people register and sign in with an e-mail address or a mobile number. This page covers e-mail. The Facebook number check covers phone numbers.
registered: true: a Facebook account is associated with the address.registered: false: a conclusive "no account".registered: null: no conclusive answer (statusandreasonsay why), not charged.
Messenger conversations run on Facebook accounts. Instagram accounts are separate, even when they are linked through Meta's Accounts Center, so Instagram has its own e-mail check.
Who uses it, and why?
- Sign-up and fake-account screening. Communities, marketplaces and apps use a "yes" as a sign that an address has a history outside their own service. A fabricated address usually doesn't. See OTP and sign-up fraud.
- Lead verification. A form lead whose address has no mailbox and no account on any large platform is often invented. See lead verification.
What do you get back?
| Field | Type | Meaning |
|---|---|---|
email, email_status | string, enum | Normalized address; valid, invalid_email, duplicate or suppressed |
checks["facebook.email"].registered | boolean or null | true account exists, false none, null unknown |
…status, …reason | enum, string | Outcome, and why an answer is not conclusive |
…confidence, …checked_at | enum, timestamp | How sure the answer is, and when it was obtained |
…cached, …billed | boolean | Cache hit, and whether it was charged |
How is it billed?
You pay per address with a conclusive answer. Real-time and bulk have separate prices, shown on pricing. You're not charged for inconclusive results (unknown, unsupported country, timeout, invalid, duplicate). Cache hits inside the freshness window are free.
What are the limits?
The check runs in real time (POST /v1/lookup, up to 100 numbers and e-mails) and in bulk jobs (POST /v1/jobs, up to 50,000). Use the code facebook.email. The alias facebook means the phone-number check. A request can hold up to 20 checks. Requests that look like sequential number ranges or generated e-mail lists are rejected: 20 or more addresses in one request on one domain that differ only by digits or separators, or, with live keys, 50 or more of one such pattern per account per UTC day.
How do I use it responsibly?
Use the check for fraud prevention and data quality on addresses your users gave you. We never read mailboxes or send e-mail to the address, and the answer is only yes, no or unknown. Don't use it to find someone's social media presence or to build audiences. The acceptable use policy forbids profiling individuals and unsolicited messaging. People can object through the opt-out form.
Example request
curl https://api.mobilevalidate.com/v1/lookup \
-H "Authorization: Bearer mv_test_publicSandboxn9ZgneuhR1B9CRfKG3fulym" \
-H "Content-Type: application/json" \
-d '{"emails":["[email protected]"],"checks":["facebook.email"]}'// npm install mobilevalidate · Node.js 20+ · save as check.mjs and run: node check.mjs
import { MobileValidate } from "mobilevalidate";
// Omit apiKey to read MOBILEVALIDATE_API_KEY from the environment.
const mv = new MobileValidate({ apiKey: "mv_test_publicSandboxn9ZgneuhR1B9CRfKG3fulym" });
const { data, error } = await mv.lookup({
emails: ["[email protected]"],
checks: ["facebook.email"],
});
if (error) console.error(error.code, error.message);
else console.dir(data.results, { depth: null });// Node.js 18+, Deno, Bun or the browser console (ES module: save as .mjs or use "type": "module").
const res = await fetch("https://api.mobilevalidate.com/v1/lookup", {
method: "POST",
headers: {
Authorization: "Bearer mv_test_publicSandboxn9ZgneuhR1B9CRfKG3fulym",
"Content-Type": "application/json",
},
body: JSON.stringify({
emails: ["[email protected]"],
checks: ["facebook.email"],
}),
});
console.log(res.status, res.headers.get("x-request-id"));
console.dir(await res.json(), { depth: null });# pip install mobilevalidate-sdk
from mobilevalidate import MobileValidate
# Omit api_key to read MOBILEVALIDATE_API_KEY from the environment.
mv = MobileValidate(api_key="mv_test_publicSandboxn9ZgneuhR1B9CRfKG3fulym")
result = mv.lookup(
emails=["[email protected]"],
checks=["facebook.email"],
)
print(result)<?php
$ch = curl_init('https://api.mobilevalidate.com/v1/lookup');
curl_setopt_array($ch, [
CURLOPT_POST => true,
CURLOPT_RETURNTRANSFER => true,
CURLOPT_HTTPHEADER => [
'Authorization: Bearer mv_test_publicSandboxn9ZgneuhR1B9CRfKG3fulym',
'Content-Type: application/json',
],
CURLOPT_POSTFIELDS => json_encode([
'emails' => ['[email protected]'],
'checks' => ['facebook.email'],
]),
]);
$response = curl_exec($ch);
echo curl_getinfo($ch, CURLINFO_RESPONSE_CODE), PHP_EOL, $response, PHP_EOL;package main
import (
"fmt"
"io"
"net/http"
"strings"
)
func main() {
body := strings.NewReader(`{"emails":["[email protected]"],"checks":["facebook.email"]}`)
req, err := http.NewRequest("POST", "https://api.mobilevalidate.com/v1/lookup", body)
if err != nil {
panic(err)
}
req.Header.Set("Authorization", "Bearer mv_test_publicSandboxn9ZgneuhR1B9CRfKG3fulym")
req.Header.Set("Content-Type", "application/json")
res, err := http.DefaultClient.Do(req)
if err != nil {
panic(err)
}
defer res.Body.Close()
out, _ := io.ReadAll(res.Body)
fmt.Println(res.Status, string(out))
}require "net/http"
require "json"
uri = URI("https://api.mobilevalidate.com/v1/lookup")
req = Net::HTTP::Post.new(uri)
req["Authorization"] = "Bearer mv_test_publicSandboxn9ZgneuhR1B9CRfKG3fulym"
req["Content-Type"] = "application/json"
req.body = JSON.generate({
"emails" => ["[email protected]"],
"checks" => ["facebook.email"]
})
res = Net::HTTP.start(uri.host, uri.port, use_ssl: true) { |http| http.request(req) }
puts res.code, res.bodyRuns as pasted with the public sandbox key, which answers the test values only. In the SDKs, omit the key to use MOBILEVALIDATE_API_KEY.
Response (excerpt, test mode: the first item of results):
{
"kind": "email",
"input": "[email protected]",
"email": "[email protected]",
"email_status": "valid",
"e164": null,
"country": null,
"checks": {
"facebook.email": {
"service": "facebook.email",
"status": "completed",
"registered": true,
"attributes": null,
"confidence": "high",
"confidence_score": 0.99,
"checked_at": "2026-09-25T14:25:46.234Z",
"cached": false,
"age_seconds": 0,
"billed": false,
"reason": null,
"poll_after_ms": null
}
},
"test": true
}Try it now
Realtime lookup via POST /v1/lookup. Every example runs as pasted: it uses the public sandbox key, which answers the test values for free. In the SDKs, omit the key to use MOBILEVALIDATE_API_KEY.
curl https://api.mobilevalidate.com/v1/lookup \
-H "Authorization: Bearer mv_test_publicSandboxn9ZgneuhR1B9CRfKG3fulym" \
-H "Content-Type: application/json" \
-d '{"emails":["[email protected]"],"checks":["facebook.email"]}'// npm install mobilevalidate · Node.js 20+ · save as check.mjs and run: node check.mjs
import { MobileValidate } from "mobilevalidate";
// Omit apiKey to read MOBILEVALIDATE_API_KEY from the environment.
const mv = new MobileValidate({ apiKey: "mv_test_publicSandboxn9ZgneuhR1B9CRfKG3fulym" });
const { data, error } = await mv.lookup({
emails: ["[email protected]"],
checks: ["facebook.email"],
});
if (error) console.error(error.code, error.message);
else console.dir(data.results, { depth: null });// Node.js 18+, Deno, Bun or the browser console (ES module: save as .mjs or use "type": "module").
const res = await fetch("https://api.mobilevalidate.com/v1/lookup", {
method: "POST",
headers: {
Authorization: "Bearer mv_test_publicSandboxn9ZgneuhR1B9CRfKG3fulym",
"Content-Type": "application/json",
},
body: JSON.stringify({
emails: ["[email protected]"],
checks: ["facebook.email"],
}),
});
console.log(res.status, res.headers.get("x-request-id"));
console.dir(await res.json(), { depth: null });# pip install mobilevalidate-sdk
from mobilevalidate import MobileValidate
# Omit api_key to read MOBILEVALIDATE_API_KEY from the environment.
mv = MobileValidate(api_key="mv_test_publicSandboxn9ZgneuhR1B9CRfKG3fulym")
result = mv.lookup(
emails=["[email protected]"],
checks=["facebook.email"],
)
print(result)<?php
$ch = curl_init('https://api.mobilevalidate.com/v1/lookup');
curl_setopt_array($ch, [
CURLOPT_POST => true,
CURLOPT_RETURNTRANSFER => true,
CURLOPT_HTTPHEADER => [
'Authorization: Bearer mv_test_publicSandboxn9ZgneuhR1B9CRfKG3fulym',
'Content-Type: application/json',
],
CURLOPT_POSTFIELDS => json_encode([
'emails' => ['[email protected]'],
'checks' => ['facebook.email'],
]),
]);
$response = curl_exec($ch);
echo curl_getinfo($ch, CURLINFO_RESPONSE_CODE), PHP_EOL, $response, PHP_EOL;package main
import (
"fmt"
"io"
"net/http"
"strings"
)
func main() {
body := strings.NewReader(`{"emails":["[email protected]"],"checks":["facebook.email"]}`)
req, err := http.NewRequest("POST", "https://api.mobilevalidate.com/v1/lookup", body)
if err != nil {
panic(err)
}
req.Header.Set("Authorization", "Bearer mv_test_publicSandboxn9ZgneuhR1B9CRfKG3fulym")
req.Header.Set("Content-Type", "application/json")
res, err := http.DefaultClient.Do(req)
if err != nil {
panic(err)
}
defer res.Body.Close()
out, _ := io.ReadAll(res.Body)
fmt.Println(res.Status, string(out))
}require "net/http"
require "json"
uri = URI("https://api.mobilevalidate.com/v1/lookup")
req = Net::HTTP::Post.new(uri)
req["Authorization"] = "Bearer mv_test_publicSandboxn9ZgneuhR1B9CRfKG3fulym"
req["Content-Type"] = "application/json"
req.body = JSON.generate({
"emails" => ["[email protected]"],
"checks" => ["facebook.email"]
})
res = Net::HTTP.start(uri.host, uri.port, use_ssl: true) { |http| http.request(req) }
puts res.code, res.body// .mcp.json (Claude Code), ~/.cursor/mcp.json (Cursor) or .vscode/mcp.json ("servers" instead of "mcpServers")
{
"mcpServers": {
"mobilevalidate": {
"type": "http",
"url": "https://mcp.mobilevalidate.com/mcp",
"headers": { "Authorization": "Bearer ${MOBILEVALIDATE_API_KEY}" }
}
}
}
// Then ask your agent, e.g.:
// "Check [email protected] with facebook.email" → tool: lookup_emailsThe hosted MCP server is live for customers with an agent key (mv_agent_…) or a test key. Or run it locally with npx -y @mobilevalidate/mcp.
Real test-mode result for this check
{
"service": "facebook.email",
"status": "completed",
"registered": true,
"attributes": null,
"confidence": "high",
"confidence_score": 0.99,
"checked_at": "2026-09-25T14:25:29.021Z",
"cached": false,
"age_seconds": 0,
"billed": false,
"reason": null,
"poll_after_ms": null
}What you get
Fields of checks["facebook.email"], generated from the public service catalog.
| Field | Type | Meaning |
|---|---|---|
| registered | boolean | null | true = found, false = not found, null = unknown (not charged). |
| status | enum | completed, pending, unknown, unsupported_country or failed. |
| checked_at | timestamp | When the answer was obtained. |
Frequently asked questions
Does the check return the Facebook profile?
No. It only answers whether a Facebook account is associated with the address: yes, no or unknown. No name, photo, profile link or friends list is ever returned.
Does the person get notified?
No. Nothing is sent to the address and no action is taken on the account.
Is a Facebook account the same as a Messenger or Instagram account?
Messenger uses Facebook accounts. Instagram accounts are separate, even though they can be linked to a Facebook account in Meta's Accounts Center. Use the Instagram e-mail check for Instagram.
What does an unknown answer cost?
Nothing. Inconclusive answers are never charged.

