Email Verification API
Trueguard's email verification API, also called an email validation API, is a REST endpoint that checks any email address for syntax, MX records, SMTP deliverability, disposable domains, catch-all behavior, role-based mailboxes, and free-mail providers in one call. 100 validations a month free, no credit card. Paid plans start at $49.99 for 50,000 validations.
100 validations a month. No credit card required.Paste an address above. Or try one of the examples below.
What does the email verification API return?
Six signals in one JSON response. Every field on every plan, including free.
Syntax
syntaxRFC 5322 grammar check. Deterministic. Malformed addresses fail here.
MX records
mxDoes the domain publish mail servers? We resolve and return what the domain advertises. No MX, no mail.
SMTP deliverability
smtpWe open a real conversation with the destination server and stop before any message is sent.
Disposable
disposableIs the address on a throwaway domain like Mailinator, Guerrilla Mail, Temp-Mail, or 10MinuteMail? Matched against a continuously updated registry of thousands.
Catch-all
catch_allIs the domain set to accept mail for every address? Flagged, and the deliverability verdict returns risky. No SMTP probe can prove a specific mailbox exists on a catch-all.
Role-based
role_basedIs this a generic shared mailbox rather than a person? Flagged so you can route role accounts differently.
Free-mail provider
free_providerGmail, Outlook, Yahoo, iCloud, Proton, Zoho. Flagged so you can treat personal addresses differently from corporate ones.
How do I verify an email with one API call?
Three steps. Most teams integrate in an afternoon.
Sign up for a free API key
No card. 100 validations a month. Same latency, same response shape, same accuracy.
Call POST /email/validation
One header. One body field. HTTPS only.
Read the JSON
Six signals, one verdict. Branch on the field that matters for your use case.
The same call in nine languages. Real working snippets. Paste, set the key, run. If your stack isn't listed, the curl translates cleanly.
curl -X POST https://api.trueguard.io/v2/email/validation \
-H "X-API-KEY: $YOUR_KEY" \
-H "Content-Type: application/json" \
-d '{"email":"founder@yourcompany.com"}'What does a typical JSON response look like?
{
"email": "realemail@gmail.com",
"rawEmail": "realemail@gmail.com",
"syntax": {
"isValid": true
},
"deliverability": {
"status": "safe",
"isSmtpValid": true,
"isMxValid": true,
"isCatchall": false,
"isInboxFull": false,
"isDeliverable": true,
"isDisabled": false,
"mxRecords": [
"alt2.gmail-smtp-in.l.google.com",
"gmail-smtp-in.l.google.com",
"alt4.gmail-smtp-in.l.google.com",
"alt1.gmail-smtp-in.l.google.com",
"alt3.gmail-smtp-in.l.google.com"
]
},
"domain": {
"name": "gmail.com",
"age": 11263,
"isLive": true,
"isRisky": false
},
"quality": {
"isDisposable": false,
"isFree": true,
"isRole": false,
"isSubaddress": false
}
}How accurate is real-time email verification?
Some checks are right every time. Others depend on the remote mail server cooperating.
<1%
False positive rate
Sub-1s
Median response time
100/month
Free API validations per month
0.001$/check
Scalable pricing
Syntax, MX, and disposable checks are deterministic. SMTP and catch-all detection depend on the destination mail server. If you need this at scale, the email verification API returns the same answer with 50,000 monthly validations on the paid plan.
How much does the email verification API cost?
Three tiers. Free plan needs no card.
Pay for what you check. Cancel anytime. Overage is billed through Stripe at $0.001 per validation regardless of volume.
What counts as a validation? One request to the validation endpoint is one validation. Failed calls (4xx from your side) do not count.
What do teams use email verification for?
One bad address costs more than you think. It bounces, it lands you on blocklists, it sneaks a fake account into your free tier, or it sits in your CRM as a dead lead. Verification is one API call that pays back across every signup you accept and every email you send.
Stop fake signups at the form
Disposable and invalid addresses shouldn't enter your database. Verify on the signup form and bounce the junk before it creates an account, eats a free-tier seat, or pollutes your conversion analytics.
Protect sender reputation
Mailbox providers penalize senders who hit dead addresses. A bounce rate above 2% gets you throttled. Above 5% you start landing in spam. Validate before the send and your deliverability stays clean.
Clean an old list before you mail it
Lists rot. People change jobs, abandon inboxes, get suspended. Run a list through verification before the next campaign and drop the dead addresses. Cheaper than the deliverability damage from sending anyway.
Qualify leads at capture
Form fills with info@, support@, or a temp-mail domain aren't real leads. Verification flags role accounts and disposables so sales spends time on contacts that can actually buy.
Frequently asked questions
What is an email verification API?
It's a REST endpoint. Given an email address, it returns whether the address is syntactically valid, has working MX records, accepts mail via SMTP, and whether the domain is disposable, catch-all, role-based, or a free provider. Call it from your backend at signup, form submit, or before a campaign sends.
How fast is real-time email verification?
Trueguard's API targets Sub-1s median response time. Slow SMTP servers push response times higher because the check waits on the remote mail server.
What's the difference between syntax validation and SMTP verification?
Syntax validation checks the email matches the RFC 5322 grammar. It catches typos. SMTP verification opens a connection to the destination mail server and checks the address is accepted without sending a message. Syntax is deterministic. SMTP is probabilistic.
Can the API detect disposable email addresses?
Yes. Trueguard maintains a continuously updated registry of disposable email domains. The same dataset powers /disposable-emails. The response includes a disposable flag plus enrichment like when the domain was first seen.
Do you support catch-all detection?
Yes. Catch-all domains accept any address at the domain. The API returns the catch-all flag and a deliverability verdict of risky. You cannot prove a specific mailbox exists on a catch-all without sending mail.
What does the API cost at scale?
The Standard plan is $49.99 a month and includes 50,000 validations. Overage is $0.001 per validation, billed through Stripe.
Is there a free tier with no credit card?
Yes. 100 validations a month, no card, no trial expiry. The free tier runs the production endpoint. Same response shape, same latency, same accuracy.
How is this different from Trueguard's main fraud-detection product?
The email verification API is a standalone product. You can buy it without using Trueguard's main verification flow. If you already run Trueguard for fake-signup prevention, you can chain email validation as one more input. Same API key, separate meter.
