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Email verification built on a real SMTP handshake.

Coalstoke confirms every address against the destination mail server, learns how each domain formats its names, and returns a documented status — not a probability score dressed up as a checkmark.

Real SMTP RCPT-TO handshake — not a pattern guess
Documented reason codes on every result
Charge-on-success — you pay only for what we find

Start free — 50 credits View API docs

50 credits · no card required · magic-link signup

POST /v1/verify200 OK

{ "email": "sarah@stripe.com" }

{
  "status": deliverable,
  "mxProvider": "google_workspace",
  "smtpCode": 250,
  "confidence": 0.98
}

deliverablecatch_allprotectedundeliverable

every verdict comes with a documented status code

Built to be trusted, not just cheap

Six primitives, one API. Every one of them exists because the alternative was a silent false-positive somewhere down the funnel.

SMTP verify

Live RCPT TO against the real mail server — not a pattern-matching guess dressed up as a check.

Catch-all detection

Accept-all domains get flagged as catch_all, not silently marked verified like most competitors do.

Pattern engine

Per-domain name patterns get smarter with every lookup — hit-rate compounds the more you use it.

Public data cascade

Falls through public sources before ever charging a credit, so free lookups stay genuinely free.

Documented status codes

Every result returns as deliverable, catch_all, protected, or undeliverable — with the SMTP response behind it. No unexplained scores.

Bulk API

10,000 items per async job, with webhook callbacks and a per-row status code.

One plan. Metered. No tiers to game.

A fixed monthly base covers the dedicated fleet. On top of that, you pay the same per-lead rate whether you send ten thousand or a million. If you send zero leads in a month, you only pay the base.

Coalstoke — everything included

$50/ mo base+$0.0012/ lead verified

Dedicated SMTP verification fleet — no shared IPs, no throttle-share with other customers
CSV drag-and-drop upload — Sales Nav, HubSpot exports, generic CSVs, headers auto-detected
Native HubSpot Private App sync — contacts land verified with LinkedIn URL populated
Master export CSV + one-click retry loop on catch-alls and deferred leads
Unlimited team seats — invite by email, shared workspace, no per-seat fees
50 free credits on signup — no card required to try it

Start with 50 free credits See a full walkthrough

At 100k leads/mo you pay $170. At 250k, $350. At 500k, $650. Metered by Stripe — cancel any time.

Live traffic · updated every 30s

79%

verified rate (7d)

6,407

verifies (7d)

1,015

finds (7d)

full dashboard →

How pricing compares

Live pricing pulled from each provider's published rate card, sorted by cost per credit. Coalstoke tiers are highlighted.

Provider	Tier	Monthly	Credits	Per credit	vs. our Growth
Coalstoke	$50 base + $0.0012/lead	$50	0	$0.0012	1.6× cheaper
Hunter.io Starter	flat	$49	500	$0.098	51.6× more
Hunter.io Pro	flat	$149	5,000	$0.030	15.8× more
Icypeas Standard	flat	$86	6,000	$0.014	7.4× more
Snov.io Pro	flat	$169	5,000	$0.034	17.9× more
Apollo.io Basic	per-seat	$59	900	$0.066	34.7× more
RocketReach Individual	flat	$53	170	$0.312	164.2× more
Findymail Grow	flat	$99	2,500	$0.040	21.1× more
ContactOut Personal	per-seat	$79	500	$0.158	83.2× more
Lusha Pro	per-seat	$99	480	$0.206	108.4× more

What it costs at your volume

Enter your monthly volume to compare Coalstoke against what you're paying today.

Your current tool

Finds per month

Team seats

Current monthly

$490

Hunter.io Starter × 1 sub

With Coalstoke (drop-in swap)

$56

Coalstoke · +$6 PAYG

You save

$434/mo · 89%

$5208/year · same volume

Cost shown reflects each provider's published plan and overage pricing at the volume entered above. No credit card required to test your own numbers.

Get your first 50 credits

One-time magic link — no password. You'll land in your dashboard already loaded.