Best email verifier for cold email: 7 tools compared

Which email verifier is built for cold email?

What it is

Email verification with a real SMTP mailbox check: each address comes back valid, risky or invalid with a reason. Includes an email finder on Pro and up.

Price per check

Starter $9/mo for 2,500 ($3.60 per 1,000); Pro $39/mo, 100,000 a month at full speed ($0.39 per 1,000 when used), then slower, never cut off. Business $99/mo with 300,000 at full speed; Agency $249/mo with 750,000 at full speed.

One-time packs

10,000 for $15 ($1.50 per 1,000); 25,000 for $29 ($1.16 per 1,000); 50,000 for $49 ($0.98 per 1,000); 100,000 for $79 ($0.79 per 1,000); 250,000 for $169 ($0.68 per 1,000). Credits never expire, run at standard speed, CSV verification only (no API or finder).

Free checks

First 100 email checks free with a Google sign-in, no card, once per account. Single checks on the free email checker need no account.

Billing

Monthly subscription, cancel anytime (yearly billing optional). One-time packs are listed above. Starter allowances reset monthly and do not roll over.

Speed today

One sending IP today, shared by every customer: about 13,000 mailbox checks a day in the standard lane. Bad syntax, dead domains and disposable addresses return at once; a list of 100,000 takes days, not hours, and each job shows its estimated finish time.

Catch-all handling

Catch-all (accept-all) addresses stay risky, never valid, and are graded higher, medium or lower likelihood with the reasons. Anything a mail server does not confirm is risky.

API and MCP

REST API on Pro, Business and Agency (Pro includes 10,000 calls a month, then $1.50 per 1,000). Remote MCP server with 6 tools for Claude, ChatGPT, Cursor and VS Code. No API on Starter.

Integrations

Connects to Instantly, Smartlead, HubSpot and Mailchimp by API key: verifies a campaign or list and tags each contact with its result. CSV in and out for any other tool.

Phone

Free phone format checks (country, type range). Live carrier and line-type lookups come with Pro + Phone at $49.99/mo (5,000 a month). It never says a number is in service.

What it does not do

No sending, warmup or inbox placement tests. No published accuracy benchmark against other verifiers. Catch-all domains, Yahoo and AOL cannot be confirmed, and Outlook.com and Hotmail mailboxes are not probed while Microsoft refuses checks from our server's network: all of these come back risky, never valid.

SimpleVerifier facts from our pricing page and product. Last updated October 31, 2026.

Which one should you pick?

• Pick SimpleVerifier if you verify or re-check lists every month and want one flat monthly price instead of credits, with catch-all addresses kept risky rather than marked valid.

  Skip SimpleVerifier if you want the lowest price for one small list, where another vendor's pack can cost less (cost by list size); you need your data processed only inside the EU (our service providers process data in several countries, including the US); or your list is mostly Outlook.com, Hotmail or Live addresses, which Microsoft currently won't let us confirm, so they come back risky (why).

• Pick MillionVerifier if you clean a very large list once in a while: 1,000,000 credits are $449 one-time, never expire, and there is no subscription to cancel.

• Pick Instantly's own verifier if you already buy Instantly credits and would rather keep verification on the same bill than connect another tool.

• Pick Smartlead's own verifier if you only verify leads that go into Smartlead and want it inside the same app.

• Pick DeBounce if you want a low price on a one-off clean of a small or medium list, with pay-as-you-go credits that never expire.

• Pick EmailListVerify if you verify a steady 5,000 to 10,000 addresses a month ($16 a month for 5,000), or want pay-as-you-go credits that never expire.

• Pick NeverBounce if you want verification synced inside many marketing tools: its pricing page lists 80+ integrations.

How we compared

On 27 October 2026 we read each vendor's pricing page and looked for Instantly and Smartlead integrations on its own integrations page or help center. We checked 10 outside verifiers; the table keeps the one that lists a connection and the three lowest-priced CSV options, and leaves out Emailable, Clearout, Bouncer, Kickbox, ZeroBounce and Hunter (no Instantly or Smartlead integration found, higher price for 10,000), which are in the main roundup. We did not run an accuracy benchmark, so nothing here ranks accuracy: test a shortlist on a sample of your own list, including addresses you know are dead.

Each tool in a few lines

1. 1. SimpleVerifier(our tool)

   Best for: Lists checked every month, re-checks, and campaign tools it connects to

   • Connects to Instantly, Smartlead, HubSpot and Mailchimp by API key and tags each contact valid, risky or invalid
   • Catch-all addresses stay risky, never valid
   • Watch out: One-time packs run at standard speed and cover CSV verification only (no API or finder)
   • Watch out: Starter's allowance resets monthly and does not roll over, and has no API; 10,000 a month needs Pro

   Checked October 27, 2026: SimpleVerifier pricing · SimpleVerifier integrations

2. 2. MillionVerifier

   Best for: Very large one-off cleans

   • 1,000,000 credits are $449 and never expire
   • No subscription to cancel
   • Watch out: No monthly plan, so a monthly re-check is a new purchase each time

   Checked October 27, 2026: MillionVerifier pricing (all packages) · MillionVerifier help: integrations

3. 3. Instantly's own verifier

   Best for: Instantly users who want one bill

   • Runs inside Instantly, so verified leads go straight into outreach
   • Watch out: Instantly credits are sold separately from the outreach plan

   Checked October 27, 2026: Instantly email verification · Instantly pricing

4. 4. Smartlead's own verifier

   Best for: Smartlead users who want verification in the same app

   • Verified lists can flow straight into a campaign
   • Watch out: No standalone per-check price on the pages we read

   Checked October 27, 2026: Smartlead email verifier · Smartlead pricing

5. 5. DeBounce

   Best for: Small and medium lists cleaned once or monthly

   • Pay-as-you-go credits never expire
   • 100,000 credits are $135 one-time
   • Watch out: Every pass over the same list is billed again

   Checked October 27, 2026: DeBounce pricing · DeBounce integrations

6. 6. EmailListVerify

   Best for: Steady lists of 5,000-10,000 a month

   • A 5,000-a-month plan is $16
   • Pay-as-you-go credits never expire
   • Watch out: The page shows euros in some regions while its structured data lists US dollars

   Checked October 27, 2026: EmailListVerify pricing · EmailListVerify integrations

7. 7. NeverBounce

   Best for: Teams that want verification synced into many marketing tools

   • Its pricing page says it works with Zapier, n8n, HubSpot, Mailchimp and 80+ integrations
   • Watch out: Pay-as-you-go credits expire 12 months after purchase

   Checked October 27, 2026: NeverBounce pricing

Common questions

Should I send cold email to catch-all addresses?

Not mixed into the main campaign. A catch-all server accepts every address, so a verifier cannot confirm the mailbox. SimpleVerifier keeps them risky, never valid, and grades them; send them in a small separate batch and watch bounces.

Which email verifier works with Instantly and Smartlead?

SimpleVerifier connects to both by API key. On 27 October 2026 MillionVerifier listed a Smartlead connection; we found no Instantly or Smartlead integration on the other vendors' sites. Instantly and Smartlead also sell their own verifiers.

How much does it cost to verify 10,000 cold email leads?

By published monthly prices: DeBounce $23, EmailListVerify $25, SimpleVerifier Pro $39, NeverBounce $49, ZeroBounce ONE $99. One-time packs: DeBounce $25, MillionVerifier $39, Bouncer $60, Kickbox $70.

What bounce rate is safe for cold email?

Keep hard bounces well under 2% per campaign; Google's bulk-sender rules also cap spam complaints at 0.3%. See what bounce rate gets an account suspended.

Is the cheapest verifier the most accurate?

We did not run an accuracy benchmark, so nothing here ranks accuracy: test a shortlist on a sample of your own list, including addresses you know are dead.