VerifyFlow

Infrastructure for
email deliverability.

Verify millions of emails per hour with 99.6% accuracy. SMTP probing, catch-all detection, risk scoring — all behind a single API.

100 free verifications No credit card SOC 2 + GDPR
app.verifyflow.com / live
LIVE
REAL-TIME STREAM
Processing campaign-export.csv
847,221 / 1,000,000
84.7%~ 14s remaining
sarah.chen@stripe.com98Valid
j.alvarez@acme.io96Valid
noreply@bot-relay.cc12Disposable
marketing@oldcorp.biz8Invalid
info@catchall-domain.com54Catch-all
RESULTS BREAKDOWN
84.1%
DELIVERABLE
Valid712,45084.1%
Invalid73,2108.6%
Catch-all38,1204.5%
Risky16,0411.9%
Disposable7,4000.9%
61,420 emails/secp95 280ms
Trusted by 9,400+ growth & deliverability teams
NorthwindLumenARC/LabsHelixFoundry★Quantaoutreach.devMailgrid
Accuracy
0.0%
vs. mailbox provider truth
Verified
0.0B
emails processed in 2026
Uptime
0.00%
SLA-backed, 365 days
p95 latency
0ms
single-record API call
Platform

Built for serious email infrastructure.

Every signal a deliverability team needs — wired into one consistent API and dashboard.

→ MAIL FROM<verify@vf.io>
→ RCPT TO<sarah@stripe.com>
← 250OK — mailbox exists
SMTP verification

Real handshake with the mail server. No pinging — confirmed mailbox existence.

acme.iomailbox
oldco.bizcatch-all
mailbox.ccmailbox
Catch-all detection

Identify accept-all domains and split them from confirmed mailboxes for safer sending.

temp-mail.ioblocked
10minutemail.comblocked
guerrilla.orgblocked
throwaway.ccblocked
Disposable & spam-trap filter

Cross-reference 4.2M known disposable domains and active spam-trap signatures.

contacts-q1.csv3,242,001 rows
chunk 41/60~ 2m 14s
Bulk CSV verification

Drop a 10M-row CSV. We chunk, dedupe, and verify in parallel — clean file back in minutes.

POST /v1/verify
{
"email": "sarah@stripe.com"
}
← 200 valid · 280ms
Realtime API

Verify a signup before the form submits. 280ms p95, edge-deployed in 14 regions.

Syntax
100
MX records
96
Mailbox
99
Reputation
82
Risk94 — low
Deliverability risk scoring

0–100 risk score per address, blending mailbox, domain reputation, and behavioral signals.

HIGH-SPEED PROCESSING
2,000,000 emails per hour. Per worker.

Bare-metal SMTP probes, connection pooling, and intelligent retry. We push deliverability infrastructure to physical limits so you don't have to.

How it works

From dirty list to clean sender, in minutes.

01
Upload

CSV, API, or sync from Salesforce, HubSpot, Klaviyo. We dedupe and normalize on ingest.

02
Verify

Multi-stage pipeline: syntax → MX → SMTP → catch-all → reputation. ~5s per 10k rows.

03
Export

Download a clean list — or sync verified contacts back to your CRM in one click.

The dashboard

Operate your sender hygiene like infrastructure.

A control plane built for deliverability engineers, not marketing dashboards.

app.verifyflow.com/dashboard
Dashboard
Upload
Verifications41
API Keys
Billing
Settings
Welcome back, Sarah
This is your verification activity for the last 30 days.
JAN 4 – FEB 3
VERIFIED
1.24M
+12.4%
VALID RATE
84.1%
+1.2pp
API CALLS
2.81M
+8.0%
P95
284ms
-12ms
Verification volume
Total Valid
019,76539,530
Breakdown
84.1%
VALID
Pricing

Volume pricing without surprises.

Every plan includes all verification checks. You only pay for valid lookups — invalid syntax is free.

Starter
For sender hygiene side projects.
$39/ mo, billed yearly
50K verifications / mo
Start free
Realtime API + bulk upload
All core checks (SMTP, catch-all, disposable)
CSV exports + Zapier sync
Email support
5 team seats
POPULAR
Growth
For high-volume marketing teams.
$199/ mo, billed yearly
500K verifications / mo
Start free
Everything in Starter
Risk scoring + reputation signals
CRM sync (HubSpot, Salesforce, Klaviyo)
Webhook event stream
Priority support + 99.9% SLA
25 team seats
Agency
For agencies & deliverability ops.
$499/ mo, billed yearly
2M verifications / mo
Start free
Everything in Growth
Multi-workspace + client billing
White-label exports
Dedicated probe IPs
Custom integrations + DPA
Unlimited seats
Enterprise
10M+ verifications, dedicated infrastructure, SAML SSO, BAA + SOC 2 Type II, named CSM.
Talk to sales
FAQ

Questions before you trust us with your sender.

We benchmark against mailbox-provider ground-truth on a rolling 7-day window. Our last published number was 99.6% precision on confirmed-deliverable addresses, 99.2% recall on hard bounces. Full methodology is published in our trust report.
Yes — for domains that respond to RCPT TO with deterministic codes. For catch-all domains, we run a multi-signal classifier (reputation, mailbox patterns, MX history) to estimate deliverability without false positives.
Verification payloads are processed in-memory and deleted within 24 hours. We never sell, share, or use your data for anything other than running the verification you requested. SOC 2 Type II audited, GDPR + DPA available.
Each domain has its own probe queue with adaptive backoff. We respect provider rate-limits and retry transient errors automatically up to 3 times. You'll never get a stale or rate-limited result back.
Yes. Our /v1/verify endpoint runs at 280ms p95 from 14 edge regions. Most signup flows wire it as a non-blocking check that surfaces a soft warning, then run a stricter pass in the background.
Annual plans roll over 100% of unused verifications to the next month. Monthly plans roll over 50%, up to one billing cycle. We don't believe in 'use it or lose it' on something you've already paid for.

Stop guessing about deliverability.

Verify your first 100 emails free. Set up takes 90 seconds. No credit card.

Start verifying