v1 · email verification API

MailGuard

Email verification API for developers: the same syntax, MX, disposable & typo checks the big providers charge for, up to 100× cheaper than the next cheapest competitors on the market, with a free tier and a 2-minute setup.

Stop bad emails at signup with one fast call.

Get a free API key

500 verifications/month, free forever. No card required.

Or try the free email checker (no signup). Already a customer? Check usage and rotate your key on the account dashboard.

Quick start

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

Response:

{
  "email": "jane@gmial.com",
  "status": "risky",
  "score": 75,
  "checks": { "syntax": true, "mx_found": true, "disposable": false, "role": false, "free_provider": false },
  "did_you_mean": "gmail.com",
  "reasons": ["Possible typo. Did you mean \"jane@gmail.com\"?"]
}

JavaScript / TypeScript SDK

Prefer a typed client? Install the official SDK from npm:

npm install mailguard
import { MailGuard } from "mailguard";

const mg = new MailGuard("YOUR_API_KEY");
const result = await mg.verify("jane@gmial.com");
// { status: "risky", score: 75, did_you_mean: "gmail.com", ... }

Zero dependencies. Works in Node, Bun, Deno, Cloudflare Workers, and the browser. View on npm · Source on GitHub.

Pricing

Free

£0
500 / month
Get free key

Starter

£5
50,000 / month
Coming soon
Email to enquire →

Pro

£19
250,000 / month
Coming soon
Email to enquire →

Scale

£49
1,000,000 / month
Coming soon
Email to enquire →

Roughly £0.00005–0.0001 per check: up to 100× cheaper than the usual £0.004–0.01.

The free tier is live now. Paid plans are coming soon; email us to register interest.

Endpoints

MethodPathDescription
POST/v1/verifyVerify one email
GET/v1/verify?email=Verify one email (querystring)
POST/v1/verify/batchVerify up to 100 at once
POST/v1/verify/csvBulk-verify a CSV / list
GET/v1/healthHealth check (no key)

Authenticate with Authorization: Bearer <key> or x-api-key: <key>.

FAQ

Is there a free email verification API tier?

Yes. You get 500 verifications a month, free, with no card required.

What does MailGuard check?

Email syntax, the domain's MX (mail server) records, disposable and role-account detection, a 'did you mean?' typo suggestion, and a 0–100 deliverability score.

Does it do SMTP mailbox verification?

No. It is a fast syntax, MX, and heuristic verifier. That keeps it cheap and is the right level for stopping bad emails at signup.

Is it GDPR compliant?

Yes. We do not store the email addresses you verify; we cache only the domain's mail-server result. See our privacy policy for detail.

How much does it cost?

Free for 500 checks a month. Paid plans start at £5/month.

Which languages and frameworks does it work with?

Any. It is a REST API, with an official npm SDK for JavaScript and TypeScript.

From the blog

ZeroBounce Alternatives: How to Choose an Email Verification Tool in 2026
A fair look at ZeroBounce alternatives by category (full suites, developer-first APIs, and self-hosted options) and how to pick the right one for your use case and budget.

How to Validate Email Addresses in JavaScript / Node.js (Beyond Regex)
Regex only proves an email looks valid, not that it can receive mail. Here's how to layer syntax, MX, and disposable checks in JavaScript/Node, with copy-paste code.

How to Reduce Your Signup Bounce Rate (a Practical Playbook)
Bad emails at signup wreck your bounce rate and sender reputation. Here's a practical, code-first playbook to stop typos, fakes, and disposable addresses before they get in.

Read all posts →