bolt Mailsfinder + Smartlead

Verify Smartlead lists before they hit your campaigns

Smartlead rotates sends across a pool of connected mailboxes, so a single dirty list spreads bounce damage across every sender in the rotation. Apollo, Sales Navigator, and scraper exports routinely carry 8 to 25% stale addresses. Mailsfinder pre-flight verifies every list via Zapier, Make, or direct API, so only deliverable contacts enter Smartlead campaigns. Bounces drop under 1%, master inbox stays clean, and warmup gains hold across multi-mailbox setups.

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check_circleBounce rate under 1% check_circle50 free credits, no card check_circleWire up via Zapier or Make

shield

Pre-flight verification

Apollo export, 10,000 leads

Raw rows imported 10,000

Invalid syntax removed 412

Hard bounces flagged 1,083

Catch-all and risky 624

Pushed to Smartlead 7,881 verified

Projected bounce rate 0.6%

Verify before send

Trusted by Smartlead operators, lead gen agencies, and SDR teams in 40+ countries

Klients Growth Outbound Labs PipelinePro DemandLoop ColdStack SDR Republic

Why Smartlead users add Mailsfinder

Three layers of protection before a single Smartlead send

Bulk pre-flight, real-time API for live campaigns, and a bounce-rate dashboard that flags risk before it ships.

fact_check

Pre-flight bulk verification

Drop a 50,000-row Apollo export and Mailsfinder runs SMTP probing, MX validation, and catch-all detection on every row. The cleaned CSV imports straight into a Smartlead campaign with zero manual scrubbing in between.

bolt

Real-time API for live campaigns

The Verifier API returns a deliverability decision in under 500ms. Wire it into a Zapier or Make webhook so leads added mid-sequence get verified in real time and only deliverable rows enter the active Smartlead cadence.

monitoring

Bounce-rate dashboard pre-send

Mailsfinder projects bounce risk before the list ever hits Smartlead. See the percentage of deliverable, catch-all, risky, and hard-bounce rows at a glance. Reject lists with risk over 3% before they touch your mailbox rotation.

How it works

From scraped list to deliverable Smartlead campaign in four steps

The same workflow whether you run one mailbox or a hundred Smartlead workspaces.

Pull list from Apollo or scraper

Export from Apollo, Sales Navigator, Clay, PhantomBuster, or any scraper. Drop it as a CSV or pipe it directly into a Make or Zapier scenario.

Mailsfinder verifies via API

Each row runs through the Verifier endpoint. SMTP probe, MX validation, role detection, catch-all check. Every email returns a status code and risk score.

Filter deliverable only

Auto-drop rows tagged hard_bounce, risky, role, and disposable. Optionally keep catch-all rows in a separate test segment for cautious warming.

Push to Smartlead campaign

The cleaned list lands in Smartlead as a new lead block. Bounce rate stays under 1%, master inbox stays clean, and warmup metrics hold across every mailbox in the rotation.

Deep dive

A Make scenario that verifies every lead before Smartlead ever sees it

The most common production setup runs five Make modules in sequence. Apollo exports a list, Mailsfinder verifies each row, a filter drops anything that is not deliverable, and Smartlead receives the cleaned contacts as a new lead batch. The whole scenario runs unattended on a schedule.

check_circle Module 1, Apollo trigger. Watch for new contacts in a saved search or pull a fresh segment on a daily cron.
check_circle Module 2, Mailsfinder Verify Email. Pass the email field, receive status, risk score, and is_catch_all flag.
check_circle Module 3, Filter. Continue only if status equals deliverable and risk_score is greater than 80.
check_circle Module 4, Smartlead Add Lead. Map first_name, last_name, company, and email into the target Smartlead campaign.
check_circle Module 5, Google Sheets log. Write verified and rejected counts to a daily QA tracker for sender reputation reviews.

POST /v1/verifier/email

{
  "email": "sarah.chen@acme.io",
  "status": "deliverable",
  "risk_score": 96,
  "is_catch_all": false,
  "is_role": false,
  "is_disposable": false,
  "mx_records": ["aspmx.l.google.com"],
  "smtp_check": "passed",
  "syntax_valid": true,
  "credits_used": 1
}

// Returned in under 500ms, ready to route into Smartlead

Pricing

Pricing that fits how Smartlead operators actually buy verification

A recurring credit pool for steady weekly list uploads. A lifetime pool for agencies running multi-client Smartlead workspaces at scale.

Monthly

For solo operators and small teams running daily Smartlead list uploads.

$9.99 /month

check300,000 credits per cycle
checkVerifies roughly 10,000 leads per day
checkFull Finder, Verifier, Enrichment APIs
check25,000 exports per month
check600 req/min rate limit
checkPriority email support

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Annual

Lock in 20% savings on a year of pre-flight verification credits.

$7.99 /month

Billed $95.88 per year

check300,000 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

For agencies verifying lists across multi-client Smartlead workspaces.

$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 overflow Smartlead campaigns

Stack on any plan. Credits never expire. Useful when a new client signs and a 500K Apollo export needs scrubbing before launch.

10K

credits

22K

credits

42K

credits

$14.99

100K

credits

$29

250K

credits

$59

Use cases

Four places Mailsfinder protects Smartlead sends

From first-time list scrub to mid-sequence re-verification, the same credit pool powers all four playbooks.

cleaning_services

Pre-campaign list scrub

Every Apollo, Sales Navigator, or scraper export gets cleaned before it touches Smartlead. Average shrinkage of 15 to 25% on the input, bounce rate under 1% on the output.

replay

Mid-sequence re-verify

For Smartlead sequences that run 30+ days, re-verify leads on day 14 before the next email step fires. Catches addresses that went stale during the campaign so bounces stay flat across the full sequence.

groups

Multi-client agency cleaning

One Lifetime credit pool covers verification across every Smartlead workspace your agency runs. Tag credits by client in the dashboard, bill through, and never juggle multiple verifier subscriptions per account.

policy

Lead vendor quality audit

Buying lists from a data vendor? Run a 5,000-row sample through Mailsfinder before paying for the full batch. If deliverability sits under 80%, push back on the invoice or renegotiate price.

FAQ

Questions Smartlead operators ask before wiring in Mailsfinder

How does a high bounce rate affect Smartlead inbox placement? expand_more

Smartlead rotates sends across your connected mailboxes, so a list with 8 to 15% bad emails spreads the bounce damage across every sending domain in the rotation. Once bounce rate creeps past 2 to 3%, the master inbox starts seeing replies land in spam, warmup metrics drop, and Google or Outlook may throttle the whole pool. Mailsfinder pre-flight verification keeps bounces under 1% so Smartlead campaigns stay in the primary inbox.

What is the recommended Apollo plus Smartlead plus Mailsfinder stack? expand_more

Export the lead segment from Apollo or Sales Navigator into a CSV or pipe it through an API trigger. Push every row through the Mailsfinder Verifier via Make, Zapier, n8n, or a direct REST call. Filter for status equal to deliverable, then import the cleaned file into Smartlead as a new lead list or attach it to an active campaign. The whole flow runs in under 10 minutes for 1,000 leads.

Can an agency run multiple Smartlead workspaces against one Mailsfinder account? expand_more

Yes. Mailsfinder bills per workspace, not per Smartlead seat or per client. One Monthly plan at $9.99/mo gives an agency 300,000 verifications per cycle to spend across every Smartlead workspace and client campaign. The Lifetime plan at $249 unlocks 2,000,000 verifications from a single shared pool, which is what most multi-client outbound agencies running Smartlead pick.

What are the Mailsfinder API rate limits for high-volume Smartlead users? expand_more

Monthly and Annual plans get 600 requests per minute on the Verifier API. The Lifetime plan caps at 300 req/min. At 600 req/min, a 50,000-lead list completes pre-flight verification in roughly 90 minutes, fast enough to scrub a list in the morning and load it into Smartlead campaigns the same afternoon.

Should I run warmup or verification first when launching a new Smartlead mailbox? expand_more

Warmup and verification solve different problems. Warmup builds reputation on a cold mailbox before any real sends. Verification protects that reputation once real campaigns start. The correct order is to warm a new mailbox for 2 to 3 weeks inside Smartlead, then layer Mailsfinder pre-flight verification on every list that will get sent through it. Skipping verification undoes the warmup gain within a single bad campaign.

How does Mailsfinder compare to Bouncer or ZeroBounce for Smartlead users? expand_more

Bouncer and ZeroBounce charge per email verified with no recurring credit pool, so a 10,000-list verification runs $40 to $70 each time. Mailsfinder bundles 300,000 verifications into the $9.99 Monthly plan, which works out to roughly $0.000033 per check. For Smartlead users running steady weekly list uploads across multiple workspaces, the recurring subscription model is dramatically cheaper than pay-as-you-go verifiers.

Does Mailsfinder support real-time verification for inbound Smartlead replies? expand_more

Yes. The Verifier API returns a deliverability decision in under 500ms per email. Smartlead users often wire this into webhook automations: when a positive reply lands in the master inbox or a new lead is added mid-campaign, Mailsfinder verifies the address in real time and only deliverable rows are routed into follow-up sequences or pushed to the CRM.

Can I top up credits if a large Smartlead campaign exceeds my monthly pool? expand_more

Yes. Credit packs stack on any plan and never expire: 10,000 credits for $5, 22,000 for $9, 42,000 for $14.99, 100,000 for $29, and 250,000 for $59. Useful when a new client signs and you need to verify a 500K-lead Apollo export before loading it into Smartlead workspaces.

Stop letting bad lists cook your Smartlead mailbox rotation

Start with 50 free credits. No card needed. Wire Mailsfinder into your Make or Zapier scenario in under 10 minutes and every list that touches Smartlead is pre-flight verified from day one.

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