Use Case

Stop Bad Emails Before They Hit Your Database

Every fake signup costs you money — in wasted email sends, polluted analytics, and support headaches. Validate emails at the point of entry and keep your data clean from day one.

bolt Under 200ms response time.: Fast enough for inline validation. Users see instant feedback without form lag.
block Block disposables and typos.: Catch tempmail.com addresses, obvious typos like "gmial.com", and role-based emails.
code Simple API integration.: REST or GraphQL — add a single API call to your form handler. Full docs and code samples included.

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Real-time validation Powered by Truelist

The hidden cost of bad signups

Invalid emails don't just bounce — they pollute your entire funnel.

trending_down Inflated CAC: You're paying to acquire "customers" who don't exist. Fake signups skew your metrics and waste ad spend.
mail Wasted email sends: Every email to an invalid address costs money and hurts your sender reputation. Bounces add up fast.
analytics Polluted analytics: Fake users throw off your conversion rates, cohort analysis, and growth metrics. Bad data leads to bad decisions.
support_agent Support overhead: Dealing with bounced welcome emails, failed password resets, and "I never signed up" complaints wastes time.

Where to add real-time validation

Signup forms: Validate emails on blur or submit. Block fakes before they create an account.
Checkout flows: Ensure order confirmations and receipts actually reach your customers.
Lead capture: Keep your CRM clean. Only pass verified leads to your sales team.

What we catch

Every validation checks for multiple risk factors in a single API call.

check Invalid syntax and formatting

check Non-existent domains

check Disposable/temporary emails

check Role-based addresses (info@, support@)

check Common typos (gmial, yaho, hotmal)

check Inactive/dead mailboxes

check Catch-all domain detection

check Known spam traps

Add validation in minutes

A single API call is all you need. Here's how simple it is.

// Validate on form submit
const response = await fetch('https://api.truelist.io/v1/verify', {
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${API_KEY}`,
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({ email: formData.email })
});

const { status, reason } = await response.json();

if (status === 'invalid') {
  showError('Please enter a valid email address');
}

Full documentation, SDKs, and code samples at /docs/api

Start validating forms today

Get your API key in 30 seconds. No credit card required.

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Frequently Asked Questions

Can't find the answer you're looking for? Reach out to our support team.

How fast is the API response?: Most validations complete in under 200ms — fast enough for inline form validation without noticeable delay.
Will this slow down my forms?: No. You can validate on blur (when the user leaves the email field) or on submit. Either way, the response is nearly instant.
What if the API is down?: We recommend failing open — if our API is unreachable, accept the email and validate it later via batch. Our uptime is 99.9%+.
Do you offer client-side validation?: API calls should be made server-side to protect your API key. You can trigger validation from the client, but the actual API call should go through your backend.
How does pricing work for API calls?: Truelist offers flat monthly pricing — validate as many emails as you need without per-email charges or credit management.