12-layer verification engine is live

Email verification that
doesn't lie to you.

Most tools stamp "valid" on addresses they can't actually confirm. Kluno runs 12 real layers and gives you a straight answer: valid, invalid, or an honest unknown.

No sign-up needed · Real-time result · Runs all 12 verification layers
12
Verification layers
3
Honest verdicts
<2s
Typical response
API
+ Clay & CSV
500
Free / month
The honest difference

Three answers. No inflated numbers.

Every verifier hits the same physics ceiling on Microsoft 365. The difference is whether they admit it, or dress up a guess as "valid."

Valid

Confirmed deliverable

A live SMTP check confirmed the mailbox exists and will accept mail. Send with confidence.

Invalid

Confirmed dead

No such mailbox, no MX, or a bad domain. Drop it before it dents your sender reputation.

Unknown

Honestly can't confirm

The provider (usually Microsoft 365) hides the answer. We say so instead of guessing "valid."

See why "unknown" exists →
The engine

12 layers on every address.

Most tools stop at an MX lookup. Kluno runs the full stack. Here are six of the twelve.

1
Syntax & typo repair
RFC-valid format check plus a did-you-mean fix for gmial.com-style typos, so you recover leads instead of dropping them.
2
DNS & MX check
Confirms the domain has live mail servers via Google DNS with a Cloudflare fallback, and spots security gateways.
3
Disposable detection
Screens against thousands of known throwaway inbox domains like Mailinator, TempMail and Guerrilla Mail.
4
Provider-aware logic
Microsoft 365, Google Workspace and Gmail each behave differently. Kluno reads each on its own terms.
5
Live SMTP conversation
Opens a real conversation with the receiving server and parses the enhanced status codes, not a stale database lookup.
6
Catch-all & role flagging
Detects catch-all domains, role accounts (info@, sales@) and likely spam traps, the addresses that quietly hurt deliverability.
Explore the product →
Simple

Up and running in minutes.

One API call, or drop a CSV in the dashboard. No configuration, no third-party keys.

🔑
Step 01

Get your API key

Sign up free and grab your key from the dashboard. 500 verifications a month, no credit card.

⚡
Step 02

Verify an address

Send a request with the email and your key. The 12-layer engine runs and typically answers in under two seconds.

✅
Step 03

Act on the result

Get a clear verdict (valid, invalid, or unknown) with the full signal breakdown.

Developer first

Clean API.
Straight answers.

One endpoint. One response. Every field you need to make a decision, and nothing dressed up. Works with any language.

🔄
Single + bulk
Verify one address in real time or run a whole list through the dashboard's CSV upload.
🔗
Clay HTTP column ready
Drop the Kluno URL into a Clay HTTP enrichment column with your key. Built alongside Clay workflows.
🟡
Honest status codes
A real unknown when a mailbox can't be confirmed, so your bounce rate stays truthful.
Read the API docs →
Endpoint
GET /api/v1/verify?email={email}&key={api_key}
Response
{
  "email": "jordan@acmecorp.com",
  "account": "jordan",
  "domain": "acmecorp.com",
  "status": "valid",
  "sub_status": "",
  "free_email": false,
  "role_based": false,
  "did_you_mean": null,
  "mx_found": true,
  "smtp_provider": "Google",
  "processed_at": "2026-07-29T10:14:00Z"
}

Clean your list the honest way.

Start with 500 free verifications a month. No credit card, no setup. See what a straight answer does to your bounce rate.

Start verifying free → View API docs