← All posts · 2026-06-18

Add Email Verification to Your Signup Form in Minutes

emailapiwebdevjavascript

Bad emails at signup (typos, fakes, throwaway inboxes) wreck your bounce rate and quietly inflate your metrics. Here's how to stop them with MailGuard in a few minutes, on any stack.

1. Get a free key

Grab one at mailguard-api.atek.workers.dev: 500 checks a month, no card.

2. Verify on the server

It's one POST. Reject undeliverable addresses, warn on risky ones:

curl https://mailguard-api.atek.workers.dev/v1/verify \
  -H "x-api-key: YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"email":"jane@gmial.com"}'

{
  "status": "risky",
  "score": 75,
  "checks": { "syntax": true, "mx_found": true, "disposable": false, "role": false },
  "did_you_mean": "gmail.com"
}

3. Or use the SDK (JavaScript / TypeScript)

npm install mailguard

import { MailGuard } from "mailguard";

const mg = new MailGuard(process.env.MAILGUARD_KEY);

const { status, did_you_mean } = await mg.verify(email);
if (status === "undeliverable") return reject("That email can't receive mail.");
if (did_you_mean) suggest(did_you_mean); // "did you mean gmail.com?"

4. Wire it into the form

On blur: call verify and, if did_you_mean is set, show "did you mean ...?" to recover typos before the user even submits.
On submit: block status === "undeliverable"; treat risky as a soft warning rather than a hard block so you don't lose legitimate users.
Always re-check server-side. Never trust the client alone.

That's it

You've now got syntax, MX, disposable/role detection, typo correction, and a deliverability score guarding your signups, in a few lines. Try any address on the free email checker, or get your key and ship it today.

Try MailGuard free — 500 verifications a month, no card required. Get a key →