Lead validator template

Next.js
React

Score a lead from its email and phone number: throwaway inboxes, typos, VoIP and temporary numbers.

A Next.js app that checks a signup or contact-form lead before it reaches your CRM. Enter an email and a phone number, and it runs both through APIVerve at once, lists every check with a pass, warning or fail, and scores the lead out of 100. Deploy it as-is to screen leads by hand, or lift the API route into your own form.

What it does

Catches fake emails: Flags disposable inboxes, domains with no mail server, and shared addresses like info@ or sales@.
Spots typos: Warns when a domain looks misspelled, like gmial.com, and suggests the fix on paid plans.
Checks the phone number: Confirms the number is real for its country and flags temporary and VoIP numbers.
Scores the lead: Starts at 100, takes 40 off per fail and 15 per warning, so you can sort or filter leads by one number.
Keeps your key private: The browser only talks to your own API route, which holds the key and limits each visitor to 10 checks a minute.

How it works

The API route: it calls both APIs, turns each response into checks, and scores the result.

app/api/validate/route.js

async function callApi(url, params) {
  const res = await fetch(`${url}?${new URLSearchParams(params)}`, {
    headers: { 'x-api-key': API_KEY },
    cache: 'no-store'
  });
  const body = await res.json().catch(() => null);
  if (!res.ok || body?.status !== 'ok') {
    throw new Error(body?.error || `APIVerve returned ${res.status}`);
  }
  return body.data;
}

/**
 * Each check is pass, warn or fail. A fail costs 40 points, a warning 15.
 * Only free-plan fields are used, so the score works on every plan.
 */
function emailChecks(d) {
  // suggestedCorrection (paid plans) can catch a typo hasTypo misses.
  const typo = d.hasTypo || !!d.suggestedCorrection;
  return [
    { label: 'Deliverable', status: d.isValid && d.isMxValid ? 'pass' : 'fail',
      detail: d.isMxValid ? 'Domain accepts mail' : 'Domain has no mail server' },
    { label: 'Not disposable', status: d.isDisposable ? 'fail' : 'pass',
      detail: d.isDisposable ? 'Throwaway inbox' : 'Permanent inbox' },
    { label: 'No typo', status: typo ? 'warn' : 'pass',
      detail: typo ? (d.suggestedCorrection ? `Did they mean ${d.suggestedCorrection}?` : 'Looks like a misspelled domain') : 'Domain spelled correctly' },
    { label: 'Personal inbox', status: d.isRoleAccount ? 'warn' : 'pass',
      detail: d.isRoleAccount ? 'Shared address (info@, sales@)' : 'Reaches a person' },
    { label: 'Work email', status: 'info',
      detail: d.isCompanyEmail ? 'Company domain' : d.isFreeEmail ? 'Free provider (Gmail, Yahoo…)' : 'Unknown provider' }
  ];
}

function phoneChecks(d) {
  return [
    { label: 'Valid number', status: d.isValid ? 'pass' : 'fail',
      detail: d.isValid ? d.formatted?.international || 'Valid' : 'Not a real number for this country' },
    { label: 'Not disposable', status: d.isDisposable ? 'fail' : 'pass',
      detail: d.isDisposable ? 'Temporary number' : 'Permanent number' },
    { label: 'Not VoIP', status: d.isVoip ? 'warn' : 'pass',
      detail: d.isVoip ? 'Internet number, easy to create' : 'Carrier-issued' },
    { label: 'Line type', status: 'info',
      detail: d.isMobile ? 'Mobile' : (d.type || 'unknown').replace(/_/g, ' ') }
  ];
}

function score(checks) {
  const penalty = checks.reduce((n, c) => n + (c.status === 'fail' ? 40 : c.status === 'warn' ? 15 : 0), 0);
  return Math.max(0, 100 - penalty);
}

See the whole file on GitHub →

Deploy it

Get a free API key
The free plan includes 200 credits a month, no card needed. Create your key.
Deploy it
Click Deploy to Vercel. Vercel copies the repo to your GitHub account and asks for APIVERVE_API_KEY: paste your key there.
Open your app
Vercel builds it and gives you a live URL, usually in about a minute. Every push to the repo redeploys it.

Try the Email Validator API — the call this template makes

Request

GETapi.apiverve.com/v1/emailvalidator?email=support%40myspace.com

Query parameters

emailstring

Verification

Format

No key required to try it. Get a key to use it in your app.

Example

{
  "status": "ok",
  "error": null,
  "data": {
    "email": "[email protected]",
    "domain": "myspace.com",
    "username": "support",
    "isRegexValid": true,
    "hasTypo": false,
    "isMxValid": true,
    "isValid": true,
    "isFreeEmail": false,
    "isCompanyEmail": true,
    "isDisposable": false,
    "isRoleAccount": true,
    "suggestedCorrection": null,
    "riskScore": 10,
    "riskLevel": "low"
  }
}