Clay email verification

Why verify outside Clay's credits?

Clay is great at finding emails through waterfalls. Validating every found email with a Clay-managed provider adds a data credit per row, and Clay's pricing page says data credits start at $0.05. On the Growth plan the effective rate is near $0.07. On a 10,000-row table that's a few hundred dollars just to check addresses you've already paid to find.

Calling MailExchange directly costs a fraction of that, and you get the full result: state, reason, and flags for catch-all, role and disposable addresses.

Set up the HTTP API column

Clay's HTTP API integration lets a column call any endpoint, send headers, and reference other columns in the JSON body.

1. In your table, add a column that uses the HTTP API integration.
2. Set the method to POST and the URL to https://mailexchange.com/api/v1/verify.
3. Add a header: Authorization with the value Bearer mx_live_your_key. Clay can store it as a workspace-level account so it isn't pasted into every table.
4. Set the body, referencing your email column (string references need quotes):

   {"email": "/Work Email"}

5. Use field extraction to pull state, reason and accept_all from the response into their own columns.
6. Add a run condition so the column only runs when the email column isn't empty. That saves a call on every row the waterfall didn't fill.
7. Test on one row, then run the column on the whole table.

A response looks like this:

{
  "email": "[email protected]",
  "state": "deliverable",
  "reason": "accepted_email",
  "accept_all": false,
  "role": false,
  "disposable": false
}

Steps follow Clay's HTTP API integration guide. Plan availability from clay.com/pricing. Both checked 2026-10-17.

Use the result in your table

• deliverable: push to your sequencer (Instantly, Smartlead, lemlist).
• risky with reason low_deliverability: a catch-all domain. Route these to a separate, slower campaign or skip them. See should you send to catch-all emails?
• undeliverable: drop the row, or send it back into the waterfall to try another provider.
• unknown: retry later. The credit is refunded.

Where to put it in your waterfall

Run the verification column after your email-finding waterfall, on the single email the waterfall settles on. If the result is undeliverable, a second waterfall pass can try the next provider, and you only verify again when a new address actually turns up. Checking every candidate from every provider multiplies the cost for no gain.

Keep the reason column. "Catch-all" and "rejected" need different handling downstream, and a single valid/invalid flag throws that difference away.

No Growth plan? Use the CSV route

Clay's pricing page lists HTTP API integrations on Growth and Enterprise only. On other plans:

1. Export the table as CSV.
2. Verify it in MailExchange. Your columns are kept, and each row gets a state and reason.
3. Import the result back into Clay, or straight into your sending tool.

Cost: Clay credits vs MailExchange

Clay data credit price from clay.com/pricing ("Data Credits start at $0.05 each"), checked 2026-10-17. Compare your own volume in the verification cost calculator.

Related

• MailExchange API reference
• Verify Apollo exports
• Zapier email verification
• Pricing