How to Get a ZeroBounce API Key

Before you start

Smart Email Verifier uses your own ZeroBounce API key. Each address goes from your browser to ZeroBounce, and ZeroBounce bills your account for the check. The extension only sets the daily limit (50 a day free, 500 a day on Premium).

You need:

• A ZeroBounce account. Sign up at zerobounce.net. The free plan includes 100 verification credits a month, which is plenty for testing and small lists.
• The extension installed. If it isn’t yet, see Getting Started.

ZeroBounce is a good pick if you care most about spam traps and abuse addresses. It flags them by name, and the extension shows them as Risky so you can remove them before you send.

Find your ZeroBounce API key

ZeroBounce creates a key for you when you sign up, so you only need to copy it.

1. Sign in to the ZeroBounce dashboard.
2. Open the API section from the left-hand menu, then choose API Keys.
3. Copy your key. If you’d rather keep this extension separate from your other tools, click to add a new key and name it Smart Email Verifier.

Tip: A separate key per tool is worth the extra 30 seconds. If you ever uninstall the extension, delete that one key and nothing else breaks.

ZeroBounce’s API documentation covers key management in more detail.

Add the key to Smart Email Verifier

1. Open the extension and click the Settings tab.
2. Paste the key into the ZeroBounce card’s API key field.
3. Click Save. The field switches to a masked preview of the key.
4. Click Test Connection. A working key shows Connected. Credits: 100 (or whatever your current balance is). The check reads your balance, so it doesn’t spend a credit.
5. Optional: set ZeroBounce as the Default Provider at the top of Settings.

The key stays in Chrome’s local storage on your device. Makeinfo never sees it, and requests go straight to api.zerobounce.net.

Next, open the Verify tab, enter an address you trust and click Verify to confirm it all works end to end.

What a ZeroBounce check costs

Each address you verify uses one ZeroBounce credit, whatever the result.

• Free plan: 100 credits a month. Good for testing and occasional single checks.
• Pay as you go: ZeroBounce’s most expensive option per check. Small packs work out to roughly $13 per 1,000 checks and get cheaper as volume grows.
• Monthly subscription: cheaper per credit if you verify every month.

Prices change, so confirm on the ZeroBounce pricing page before you buy. Your credit balance and the extension’s daily limit are separate. When either one runs out, verification stops for the day.

Comparing options? Which provider should I use? puts all three side by side.

Troubleshooting

Test Connection says “Invalid API key.”

ZeroBounce didn’t recognise the key. Copy it again from API Keys, making sure there’s no space at either end, and click Save. If you deleted that key in ZeroBounce, create a new one.

Test Connection shows “HTTP” and a number

The request reached ZeroBounce but failed. Wait a minute and try again. If it keeps failing, sign in to ZeroBounce and look for a billing or suspension notice on your account.

Credits show 0

Your free monthly credits are used up, or your paid balance has run out. Until you top up, checks will come back as Unknown. Your daily limit in the extension won’t help here, because the provider is what stopped answering.

Lots of results come back as Risky

That’s ZeroBounce doing its job. Risky covers spam traps, known complainers and “do not mail” addresses. See what each result status means before you decide what to keep.

Need a hand? Email [email protected] with the exact message you see (but never the key itself).