Which Email Verification Provider Should I Use?

The short answer

Choosing an email verification provider matters less than people think. All three catch the addresses that hurt you most: ones that don’t exist and domains with no mail server. The real differences are price, free credits, and how much detail you get on risky addresses.

• Just testing, or checking a few addresses a week? Start with ZeroBounce. Its 100 free credits a month cost you nothing.
• Cleaning big lists and watching cost? Use MillionVerifier. It’s usually the cheapest per check, and credits never expire.
• Sending cold email where spam traps are a real risk? Use ZeroBounce. It names spam traps and abuse addresses, and the extension shows them as Risky.
• Already paying for NeverBounce through another tool? Keep using it. There’s no reason to switch.

Smart Email Verifier works the same with every provider. You can switch at any time in Settings → Default Provider.

Side-by-side comparison

Prices are approximate pay-as-you-go rates at around 10,000 checks, as of October 2026. Always confirm on each provider’s pricing page before buying.

	NeverBounce	ZeroBounce	MillionVerifier
Approx. cost per 1,000 checks	~$8	~$13 (cheaper on a subscription)	~$4
Free credits	Small one-off batch at signup	100 every month	Small trial batch at signup
Credits expire?	No	No	No
Spam traps flagged by name	No	Yes, shown as Risky	No
Disposable inboxes	Shown as Invalid	Shown as Risky (“do not mail”)	Currently shown as Unknown
Catch-all domains	Shown as Catch-All	Shown as Catch-All	Shown as Catch-All
Does Test Connection use a credit?	No	No (also shows your balance)	Yes, one credit
Setup guide	NeverBounce API key	ZeroBounce API key	MillionVerifier API key

Whichever you choose, the extension’s own daily limit still applies: 50 checks a day on Free, 500 on Premium, reset at midnight UTC. The provider’s credits and the extension’s limit run separately, and verification stops when either one runs out.

Choose NeverBounce if…

• You already have NeverBounce credits from another tool or a past purchase.
• You want a middle-of-the-road price with a well-known brand that your team already trusts.
• You like one key per tool. NeverBounce makes you create a separate “app” for each connection, so you can revoke the extension’s access without touching anything else.

Skip it if you’re on a tight budget. MillionVerifier does the same core job for about half the price.

Choose ZeroBounce if…

• You’re on the free plan and verify occasionally. 100 free credits every month covers single checks and small lists at no cost.
• Sender reputation is the priority. ZeroBounce labels spam traps, abuse addresses and “do not mail” addresses, and the extension shows them as Risky. One spam trap in a cold campaign can do more damage than ten bounces.
• You want to see your balance in the popup. Test Connection shows your remaining ZeroBounce credits.

Skip it for big one-off cleans. On pay as you go, it’s the most expensive of the three.

Choose MillionVerifier if…

• Cost per check matters most. At around $4 per 1,000 it’s usually the cheapest option, and the gap grows on bigger packs.
• You verify in bursts. Credits never expire, so you can buy once and use them over months.
• You mostly need a clear yes or no. For removing dead addresses before a send, MillionVerifier is all you need.

Skip it if you need detail on why an address is risky. Its disposable results also currently show as Unknown in the extension.

Using more than one provider

You can save keys for all three providers. Each one keeps its own key in Settings, and the Verify tab lets you pick a provider for each run.

A pattern that works well:

1. Run the whole list on MillionVerifier to remove obvious dead addresses cheaply.
2. Re-check only the Unknown and Catch-All results on ZeroBounce. A second opinion on the uncertain ones usually settles most of them, and it costs far less than running the full list twice.

Every check uses one credit with that provider and one check from your daily limit in the extension, so re-check only the results you’re unsure about.

Not sure what a status means? See what each result status means. For the bigger picture on why this matters, read what happens when you send to invalid addresses.