LISTPROOF/ v1.4
Doc · LandingRev · 2026-04Scale · 1:1For · Outbound opsSheet 01 / 10
Apollo → Instantly · Smartlead · Lemlist

Stop sending
cold emails to
unverified Apollo leads.

LISTPROOF is the 10-second hygiene layer between your Apollo export and your sequencer. Drop a CSV — three clean lists come out.

29 €/mo·no commitment·no data stored·local API key
~ /listproof/apollo_export_oct.csv3,217 rows
$ listproof check apollo_export_oct.csv
  ↳ parse · dns-mx · smtp · catch-all probe
SAFE   1,922 (59.7%)
VERIFY 812 (25.2%)
REMOVE 483 (15.0%)
  ↳ exported: clean.csv · verify.csv · removed.csv
$

Your Apollo export is killing your domain.

Apollo is great for sourcing. But 1 lead in 6 is a landmine in your sequencer — catch-all, disposable, nxdomain, free provider. A single batch is enough to wreck weeks of warmup.

◆ Fig. 02
≈17%
risky
of raw Apollo exports contain risky or undeliverable emails.
<5%
max bounce
tolerated by Gmail / Outlook. Above that, sender reputation tanks.
1
batch
of dirty leads is enough to burn a warmed domain for 4–6 weeks.

We burned 3 domains in 2 months. Since we run every export through ListProof, zero incidents — and we save 20 min per batch.

Marc D.
Head of Outbound · Agency

3 steps. 10 seconds. Zero magic.

No AI, no black box. A stack of deterministic checks — the same ones you'd run by hand, but in parallel and at scale.

◆ Fig. 03
Deliverability references: RFC 5321 (SMTP), Gmail Postmaster Tools, Apollo documentation.
STEP 01
CSV · 3,217

Drop your Apollo CSV

Drag in any Apollo export. The email column is auto-detected. No data is stored on the server.

STEP 02
SYNDNSSMTPCADSPPARALLEL · 2.4s

5-layer pipeline in 2–4s

Syntax → DNS/MX → SMTP handshake → catch-all probe → disposable & free-provider detection. Parallel, non-blocking.

STEP 03
INPUTclean.csvverify.csvremoved.csv

3 clean files out

clean.csv (safe), verify.csv (manual), removed.csv (traceability). Ready to import into your sequencer.

3 buckets. Nothing else.

An email lands in one bucket and only one. The criteria are deterministic and documented — no fuzzy score, no confidence %.

◆ Fig. 04
SAFE59.7%

Send-safe

  • [01]Valid RFC 5322 syntax
  • [02]MX record resolved
  • [03]SMTP handshake · 250 OK
  • [04]No catch-all
  • [05]Business domain (not gmail/outlook)
→ clean.csv · ready for the sequencer
VERIFY25.2%

To verify

  • [01]Valid RFC 5322 syntax
  • [02]MX record resolved
  • [03]Free provider (gmail, outlook…)
  • [04]Or: catch-all detected
  • [05]Ambiguous SMTP response
→ verify.csv · manual review before sending
REMOVE15.0%

To exclude

  • [01]Invalid syntax
  • [02]Or: nxdomain / MX fail
  • [03]Or: disposable domain (mailinator…)
  • [04]Or: SMTP 550/553
  • [05]Or: role-based (info@, contact@)
→ removed.csv · archived, will not be sent

The screen you'll use every week.

Batch done in 2.3 seconds. Global health score, per-category breakdown, filterable table, one-click exports. That's it.

◆ Fig. 05
Job · #1204Src · apollo_export_oct.csvRows · 3,217Dur · 2.3s● Completed

Apollo export — classified

Health score
74/100
▲ acceptable · cleanup advised
SAFE59.7%
1,922
Ready to send
VERIFY25.2%
812
Manual review
REMOVE15.0%
483
Invalid · risky
⌕ filter: email, domain, status…
StatusEmailNameCompanyReason
safesarah.k@tech.ioSarah K.Stripemx · smtp 250
verifyjessica.l@gmail.comJessica L.Rampfree provider
verifydavid.p@company.comDavid P.Vercelcatch-all
removejohn.d@acmecorp.comJohn D.Acmenxdomain
removetom.h@mailinator.comTom H.disposable
safebrian.t@agency.netBrian T.Superhumanmx · smtp 250

Between your sources and your sequencers.

ListProof replaces nothing. It slots in. One CSV in, one CSV out — compatible with the whole standard outbound stack.

◆ Fig. 06
Sources · IN
A
Apollo.io
Native CSV export · local API key
H
HubSpot
Lists CSV export
C
Clay
CSV or webhook
L
LinkedIn Sales Nav
Via Apollo / Clay
PROOF
Sequencers · OUT
Instantly
Direct clean.csv push
I
Smartlead
Direct clean.csv push
S
Lemlist
CSV compatible
L
Outreach
CSV compatible
O

One plan. One price. No surprise.

No monthly email quota that blows up at the worst moment. No freemium tier built to frustrate you. One operator = one subscription.

◆ Fig. 07
◆ Solo · OperatorOne plan · one price
29€/mo
Billed monthly · No commitment
1-click cancellation · 14-day refund
◆ Everything included
  • [01]Unlimited batchesno quota, no monthly cap
  • [02]Unlimited verified emailsno credits, no top-ups
  • [03]5-layer verificationsyntax · DNS · SMTP · catch-all · disposable
  • [04]Export .csv · .xlsx · .jsondirect push to Instantly / Smartlead
  • [05]Job history90 days, viewable and re-exportable
  • [06]No data storedemails are purged after export
  • [07]Email support · 24hdirectly with the founder
◆ ComparisonNeverbounce / ZeroBounce / Hunter charge per credit ($10/1k emails ≈ $30+/mo for normal outbound usage). ListProof: flat 29€, unlimited, built for the Apollo → sequencer loop.

Frequently asked questions.

If your question isn't here, hello@listproof.io — reply within 24h, directly from the founder.

◆ Fig. 08
Q.01

Is my Apollo data stored?

No. Emails are processed in memory during the batch, then purged as soon as you download the exports. Your Apollo API key stays in your browser — it never reaches our servers.

Q.02

How is this different from NeverBounce / ZeroBounce?

Those tools sell generic, per-credit verification built for every use case. ListProof is purpose-built for the Apollo → cold-email sequencer loop: a SAFE/VERIFY/REMOVE taxonomy aligned with send decisions, a flat fee, and zero import friction.

Q.03

How accurate is the classification?

98.2% on a corpus of 50k emails tested against real bounce data (30 days). False positives always land in VERIFY, never in SAFE — by design, we'd rather be too cautious than too confident.

Q.04

How long for a 10k-lead batch?

≈ 8 seconds. The pipeline runs 5 checks in parallel. For 100k, expect about 1 min 20.

Q.05

Is there an API?

Not yet. V2 is planned for Q3 2026. For now: CSV in, CSV out — which covers 95% of outbound workflows.

Q.06

Can I try before paying?

Yes: your first batch (up to 500 emails) is free, no card. Then 29€/mo if you continue, with a no-questions 14-day refund.

◆ Next step

Stop torching
your domains. Now.

No card · 14-day refund · 1-click cancel
LISTPROOF/ v1.4

The 10-second hygiene layer between your Apollo export and your sequencer. Built for outbound operators.

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