New Playbook: Cold Email Infrastructure Setup Guide

Read Now arrow_forward
Mailsfinder Mailsfinder
Mailsfinder Mailsfinder
Pricing
Compare
Contact
Log In Start Free Trial
mark_email_read Built for Email Marketing Teams

Email verification built for email marketing teams who care about deliverability

Verify your full subscriber list before every campaign send. Block spam traps, role accounts, and dead addresses from ever touching your sending domain. Mailsfinder gives lifecycle, CRM, and newsletter teams 300,000 verification credits per cycle on the Monthly plan at $9.99, enough to scrub a 100,000-contact list three times every month.

Start Free Trial arrow_forward Talk to Sales calendar_month
check_circle50 free credits, no card check_circle99% accuracy check_circle30+ ESP integrations
cleaning_services
Pre-send list scrub
Newsletter, 98,420 contacts
Valid, ready to send 91,205
Invalid, removed 4,118
Role accounts, suppressed 1,840
Accept-all, flagged 1,257
Projected bounce rate 0.8%, down from 5.6%
Inbox placement, protected

Trusted by lifecycle, newsletter, and CRM marketing teams across SaaS and eCommerce

Klaviyo Mailchimp HubSpot ActiveCampaign Brevo Customer.io
Why email marketers pick Mailsfinder

Three layers of protection on every send

Bulk pre-send hygiene, real-time signup verification, and native ESP integrations. The full deliverability stack in one tool.

checklist

Bulk pre-send verification

Upload a 100,000-contact CSV or pull a segment straight from your ESP. Mailsfinder runs SMTP probes, MX validation, role-account detection, and accept-all flagging on every row. Cleaned list lands back in your ESP before the campaign goes out.

bolt

Real-time API form check

Wire the Verifier API into your signup form, lead magnet, or checkout. Block typos, disposable domains, and known spam traps at the moment of entry. 600 requests per minute on the Monthly plan is enough for any consumer-scale form.

hub

30+ ESP integrations

Klaviyo, Mailchimp, HubSpot, ActiveCampaign, Brevo, MailerLite, Customer.io, and more. Pull a segment, verify it, and sync the cleaned list back without a manual export. Zapier, Make, and n8n cover any ESP not on the native list.

How it works

From dirty subscriber list to clean campaign send in four steps

The same workflow whether you are sending a weekly newsletter or running a 12-flow lifecycle program.

1

Upload list or connect ESP

Drop a CSV, paste a segment, or connect Klaviyo, Mailchimp, HubSpot, or ActiveCampaign with a single OAuth click. No engineering needed.

2

Verify the list

Every address runs through SMTP, MX, syntax, role-account, and accept-all checks. A 100K list finishes in roughly 30 to 90 minutes depending on domain mix.

3

Get a clean list

Results come back tagged: valid, invalid, role, accept-all, disposable. Download a clean CSV or use the in-app filters to slice the segment any way you want.

4

Sync back to ESP

Push the cleaned segment back into Klaviyo, Mailchimp, HubSpot, or your CRM. Suppress invalid addresses and ship the campaign with bounce-safe data.

Deep dive

Real-time API verification on every signup, lead magnet, and checkout

The cheapest place to catch a bad email is the signup form. Mailsfinder's Verifier API returns a verdict in under 2 seconds, so your form can reject typos, disposable domains, and known spam traps before the address ever enters your list.

  • check_circle Block typos. "gmial.com", "yaho.com", and other fat-finger errors return invalid instantly.
  • check_circle Reject disposable domains. Mailinator, 10minutemail, and 15,000+ throwaway domains flagged on every request.
  • check_circle Catch role accounts at the door. Filter info@, sales@, support@ if your B2C program does not want them.
  • check_circle 600 req/min rate limit. Plenty of headroom for any consumer signup flow, including viral spikes.
verify-on-signup.sh 
curl -X POST https://api.mailsfinder.com/v1/verify \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"email": "sarah@acme.io"}'

{
  "email": "sarah@acme.io",
  "status": "valid",
  "score": 98,
  "mx_found": true,
  "smtp_check": "passed",
  "role_account": false,
  "accept_all": false,
  "disposable": false,
  "spam_trap_risk": "low"
}

// Returns a verdict in under 2 seconds, every time

Pricing

Pricing that fits how marketing teams actually clean lists

Pick a recurring plan for steady monthly hygiene. Pick Lifetime when you want a verification pool that never expires.

Most Popular

Monthly

For lifecycle, CRM, and newsletter teams running steady monthly sends.

$9.99 /month
  • check300,000 verification credits per cycle
  • checkFull Finder, Verifier, Enrichment APIs
  • check25,000 exports per month
  • check600 req/min rate limit
  • checkUnlimited Signals
  • checkPriority email support
Start Free Trial

Annual

Lock in 20% savings on a year of verification credits paid up front.

$7.99 /month

Billed $95.88 per year

  • check300,000 verification credits per cycle
  • checkFull Finder, Verifier, Enrichment APIs
  • check25,000 exports per month
  • check600 req/min rate limit
  • checkUnlimited Signals
  • checkPriority email support
Choose Annual

Lifetime

One-time payment, two million verification credits, no recurring bill.

$249 one-time
  • check2,000,000 credits (lifetime pool)
  • checkFinder and Verifier APIs
  • check5,000 exports per month
  • check1,000 Enrichment calls per month
  • check25 Signals per month
  • check300 req/min, lifetime access
Get Lifetime

Top-up credit packs for big re-engagement campaigns

Stack on any plan. Credits never expire. Useful when you are cleaning a dormant 500K list before a reactivation series.

10K
credits
$5
22K
credits
$9
42K
credits
$14.99
100K
credits
$29
250K
credits
$59
Email marketing use cases

Built for the four marketing motions that lose money to bounces

Newsletters, lifecycle CRM, eCommerce promos, and B2B SaaS onboarding. One verification pool, four playbooks.

newspaper

Newsletter teams

Run a monthly hygiene pass on your full subscriber base before the weekly send. Catch the 4 to 6 percent of addresses that went bad since your last clean and protect the open rates that drive sponsorship revenue.

timeline

CRM marketers

Verify dormant segments before re-engagement flows kick in. Spam traps love to live in lists that have not been emailed for 12+ months, so a pre-flight scrub is the difference between recovering revenue and getting blacklisted.

shopping_bag

eCommerce promos

Black Friday, Cyclic, and major drop emails need to hit the inbox or the campaign is dead. Verify the buyer list 48 hours before send so the promo lands at Gmail and Yahoo instead of bouncing into oblivion.

rocket_launch

B2B SaaS lifecycle

Verify the signup queue with the real-time API so onboarding sequences only fire at real inboxes. Stop wasting trial nurture sends on fake addresses and protect the product email sender reputation.

FAQ

Questions email marketing teams ask before signing up

Does Mailsfinder integrate with Klaviyo, Mailchimp, HubSpot, and ActiveCampaign? expand_more
Yes. Mailsfinder connects to 30+ ESPs and CRMs including Klaviyo, Mailchimp, HubSpot, ActiveCampaign, Brevo, MailerLite, and Customer.io through native integrations, Zapier, Make, and n8n. You can pull a segment, verify it, and sync the cleaned list back with the bounce-prone addresses removed or tagged.
How does Mailsfinder help me meet the Google and Yahoo 2024 sender requirements? expand_more
The 2024 sender rules require bulk senders to keep spam complaint rates under 0.3% and bounce rates low. Mailsfinder verification removes invalid addresses, role accounts, and spam-trap candidates before send, which directly lowers your bounce rate and protects your sender reputation. Combined with DMARC, SPF, and DKIM on your sending domain, verification is a non-optional step under the new rules.
Can Mailsfinder detect spam traps in my email marketing list? expand_more
Mailsfinder flags addresses that show classic spam-trap signals: never-engaged old contacts on disposable domains, abandoned mailbox patterns, and known seed-list domains. No verifier can guarantee 100% spam-trap detection because pristine traps look like real inboxes, but the layered checks remove the majority of risky addresses before they damage your sender score.
What are the real-time API rate limits for form signup verification? expand_more
Monthly and Annual plans get 600 requests per minute on the Verifier API. The Lifetime plan caps at 300 req/min. For a SaaS or eCommerce site doing 10,000 signups per day, 600 req/min is far more headroom than you need. The API returns a verification result in under 2 seconds for most lookups.
Is Mailsfinder GDPR compliant for verifying European subscriber lists? expand_more
Mailsfinder processes verification requests as a data processor on behalf of the marketing team that uploaded the list. We do not store verified email addresses long-term, do not resell list data, and provide a DPA on request. For EU subscriber lists, verification falls under legitimate interest when the goal is protecting deliverability of consent-based marketing sends.
How does Mailsfinder handle accept-all (catch-all) and role-based addresses? expand_more
Catch-all domains accept every address at the SMTP level, so we tag those results as 'accept-all' rather than valid or invalid. Role accounts like info@, sales@, and support@ are flagged separately so you can exclude them from promotional sends but keep them for B2B transactional flows. Each marketing team decides whether to keep, exclude, or send a re-engagement series to these segments.
How often should an email marketing team verify their list? expand_more
For active newsletters and lifecycle programs, a monthly hygiene pass on the engaged segment plus a full re-verification of any segment older than 6 months is the baseline. Real-time API verification on the signup form prevents bad addresses from entering the list at all, which is the cheapest place to catch them. ESP migrations and dormant-list reactivation campaigns also call for a full re-verification.
Will verifying my list with Mailsfinder really lower my bounce rate? expand_more
Yes. Teams that move from no verification to pre-send verification typically see bounce rates drop from 4 to 8 percent down to under 2 percent within one or two send cycles. Lower bounces lead to better inbox placement at Gmail and Yahoo, which lifts open rates and click-through rates across the entire program.

Protect your sender reputation before the next send

Start with 50 free credits. No card needed. Move to the Monthly plan when your team is ready for steady list hygiene, or grab the Lifetime plan for a verification pool that never expires.

Start Free Trial arrow_forward Talk to Sales calendar_month