How to Get a MillionVerifier API Key

Before you start

Smart Email Verifier sends each address to MillionVerifier using your own API key. MillionVerifier charges your account per check, and the extension sets the daily limit (50 a day free, 500 a day on Premium).

You need:

• A MillionVerifier account. Register at app.millionverifier.com. New accounts get a few trial credits, enough to confirm the setup works.
• The extension installed. If you haven’t done this yet, see Getting Started.

MillionVerifier is usually the cheapest per check, and its credits don’t expire. That makes it a sensible default if you verify big lists now and then rather than every day.

Find your MillionVerifier API key

1. Sign in to the MillionVerifier dashboard.
2. Open the API page from the main menu.
3. Copy the API key shown there. Copy the whole string with no spaces at either end.

Note: MillionVerifier uses one API key per account. If you regenerate it, every tool using the old key stops working, including this extension. Paste the new key into Settings after any reset.

The MillionVerifier API docs explain the key and its endpoints if you need more detail.

Add the key to Smart Email Verifier

1. Open the extension and go to the Settings tab.
2. Paste the key into the MillionVerifier card.
3. Click Save. The field switches to a masked preview.
4. Click Test Connection. A working key shows Connected successfully.
5. Optional: pick MillionVerifier as the Default Provider at the top of Settings.

Heads up: MillionVerifier has no free “check my key” endpoint. To test the connection, the extension verifies [email protected], which uses one MillionVerifier credit. It doesn’t count against your daily limit in the extension.

Your key is saved in Chrome’s local storage on this device only. Makeinfo never receives it, and requests go straight to api.millionverifier.com.

What a MillionVerifier check costs

Each address uses one MillionVerifier credit. Because credits never expire, you can buy a bigger pack once and use it over months.

At typical volumes, MillionVerifier works out to around $4 per 1,000 checks, often half the price of the other two providers or less. Bigger packs are cheaper still. Prices change, so confirm on the MillionVerifier pricing page.

The trade-off: MillionVerifier gives fewer details on why an address is bad than ZeroBounce does. For most cleaning jobs that doesn’t matter. If you need spam traps flagged by name, read Which provider should I use?

Troubleshooting

Test Connection shows an error message

The message is MillionVerifier’s own response. Most often the key is wrong or has been regenerated. Copy it again from the API page and click Save.

Results come back as Unknown with an error

When MillionVerifier returns an error (for example, out of credits or an invalid key), the extension marks that address Unknown. Check your credit balance on the MillionVerifier dashboard first.

Disposable addresses show as Unknown

MillionVerifier labels temporary inboxes “disposable”. The extension doesn’t have a separate badge for that yet, so they currently show as Unknown. Treat Unknown results from MillionVerifier as “don’t send” until you’ve checked them. The result statuses guide explains each status.

Still stuck? Email [email protected] with the exact error (never send the key).