Verify every email on your list. Even the catch-alls.
Two verification engines in sequence catch the catch-all and unknown addresses single-engine tools give up on. Definitive results for every address on your list.
No credit card. 100 free credits.
76%
Deliverable, quality grade A
Verification results
10,247 / 10,247- of catch-alls resolved
- 72%of catch-alls resolved
- average API verify
- 500msaverage API verify
- Credits never expire
- Credits never expire
Free email verifier
Free email verifier, check any address
The same two-pass engine that powers our paid verifications. 5 free checks per day, no signup required.
Want more detail? See the full free verifier page.
The difference
Single-engine verifiers leave 25% of your list as “unknown.”
Catch-all domains accept mail for any address, including ones that don’t exist. Standard verifiers can’t tell the difference, so they hedge and mark them all as unknown. We resolve them with a second pass that does deep SMTP-level verification.
Pass 01
Primary engine
Validates syntax, DNS, MX records, and SMTP mailbox existence. Runs 20 concurrent checks per list. Resolves 70-85% of emails in under a minute and flags the rest for the second pass.
Pass 02
Catch-all engine
Re-verifies catch-all and unknown results with deep SMTP-level verification and waterfall routing. Turns “unknown” into “deliverable” or “risky” for every remaining address on the list.
How it works
Three steps from raw list to clean export.
Drop CSV or click to browse
Up to 50MB · 1M rows max
client_list_q4.csv
10,247 unique emails · 64 duplicates removed
Drop a CSV. We handle the rest.
Drag and drop a list up to 1 million rows. We auto-detect the email column, deduplicate, and show a preview with the exact credit cost before you start. No column mapping, no manual setup.
Deliverable
6,964
Undeliverable
2,098
Risky
138
Two passes run in parallel batches.
Pass 1 fires off in 20-concurrent batches against every email. Pass 2 only re-verifies catch-all and unknown results from the first pass. Watch progress live in the dashboard.
All results
client_list_q4_all.csv
Deliverable only
client_list_q4_deliverable.csv
Undeliverable only
client_list_q4_undeliverable.csv
Download exactly what you need.
Export the full list, just the deliverable subset, or a flagged-only file. Filenames preserve your original CSV name with the export type appended.
API
Built for engineers who don’t want to build this themselves.
A REST API with predictable JSON responses, full CSV bulk processing, and webhook delivery for async jobs. Verify a single email in 200ms or process a million overnight.
# Verify a single email
curl https://www.leadlistverifier.com/api/v1/verify \
-H "Authorization: Bearer llv_..." \
-d "email=alex@acme.io"
# Response
{
"email": "alex@acme.io",
"result": "deliverable",
"score": 96,
"engine": "primary",
"is_role": false,
"is_free": false
}Recover your catch-all leads
The 25% of B2B addresses other tools mark unknown, resolved into a real verdict.
Microsoft 365, Google Workspace, and ESP-protected domains.
Watch progress live
The dashboard updates every five seconds, so you are never waiting blind.
Never pay for failures
If a job fails midway, your credits return to your balance instantly.
Upload a million rows
Drag in a 50MB CSV and we detect the email column automatically.
Credits that never expire
Buy a pack once and use it whenever, with no minimums or auto-renewals.
Pricing
Pay once. Use whenever. Credits don’t expire.
All plans include two-pass verification, API access, and CSV export. Credits never expire.
Is the email checker really free?
Yes. Verify up to 5 emails per day from any IP, no signup required. Need more? 100 free credits on signup, then pay-as-you-go credit packs that never expire.
How does two-pass verification actually work?
Pass 1 runs syntax, DNS, MX, and SMTP mailbox checks. Pass 2 only fires for catch-all and unknown results from Pass 1. The second pass uses deep SMTP-level verification to resolve the addresses single-engine tools mark as unknown.
Do credits expire?
No. Credits never expire. Buy them when you need them, use them whenever. There are no monthly fees, no auto-renewals, no minimum commitments.
What happens if a verification job fails?
Credits are automatically refunded in full. You're never charged for a failed verification. The refund posts instantly to your transaction history.
How fast is verification?
20 concurrent primary checks plus 5 concurrent catch-all checks per list. A 10,000-email list typically completes in 10–15 minutes. Progress updates live every 5 seconds in the dashboard.
Is there an API?
Yes. A REST API with key-based auth, single and bulk endpoints, JSON responses, and webhook delivery for async jobs. Full reference at /api-docs.
What file formats are supported?
CSV and TXT, up to 50MB and 1,000,000 rows. The email column is auto-detected. No manual column mapping required.
See your list resolved.
Sign up in 30 seconds. Verify your first list with 100 free credits.