Cold Outreach Deliverability

Verify Prospects Before You Send

Clean Outreach Lists & Protect Your Sender Reputation

Cold lists decay — people change jobs, mailboxes disappear, domains lapse. MailRook Email Validation re-checks every address in real time: mailbox existence, dead domains, disposable providers, catch-alls, and enterprise gateways. Send to real inboxes, keep bounces low.

Re-verifies mailbox existence in real time
Flags Proofpoint, Mimecast & 8 more gateways
100 free checks per day

Check a prospect — see deliverability and gateway in one go.

Checking syntax, MX, SMTP, trust, gateway, and domain profile…

What we check
Mailbox exists and accepts email
Not a disposable address
Not a role or team inbox
Not a catch-all domain
Known mail provider lookup
Enterprise gateway detection
Company and domain profile
API and MCP-ready result
The Problem

Cold Lists Rot — and Every Bounce Costs You

A prospect list goes stale the moment you stop using it. Sending to addresses that no longer exist spikes your bounce rate, drags down your sender reputation, and lands your real prospects in spam.

~30%

B2B Data Decays Yearly

People switch jobs and companies retire mailboxes — work emails go dead faster than any other type.

Bounces Hurt Reputation

High bounce rates tell mailbox providers your data is bad — future sends get throttled or spam-foldered.

Catch-Alls Lie

Catch-all domains accept anything, so a "valid" result can still bounce. You need to know which is which.

Gateways Filter You

Prospects behind Proofpoint or Mimecast scrutinise cold mail aggressively — blind sending wastes the touch.

Multi-Level Cleaning

Every Layer an Outreach Send Depends On

MailRook Email Validation runs each address through the full stack of checks that decide whether a cold email lands — and returns a clear verdict for every one.

Mailbox Existence

Direct SMTP verification confirms the mailbox still accepts mail — the headline deliverability fact for any cold send.

Dead Domain Removal

Drops addresses on domains that no longer exist or have no MX records — a fast, hard fail before you waste a send.

Disposable & Temp Detection

Strips throwaway and temporary addresses — including new burner domains hiding on shared disposable infrastructure.

Catch-All Detection

Flags accept-all domains where a positive result can't be trusted, so you can decide how much risk to take.

Role Account Flagging

Identifies generic mailboxes (info@, sales@, support@) that aren't a real person — so you target decision-makers.

Gateway Detection

Detects enterprise SEGs and returns a protection level — see secure email gateway detection.

Beyond Deliverability

Know Who's Behind a Security Gateway

A deliverable address can still be a hard target. Prospects behind Proofpoint, Mimecast, or Barracuda scan cold mail aggressively. MailRook Email Validation tells you the protection level of every address, so you can segment your sequences instead of burning reputation on blind sends.

None

No Gateway

Standard spam filters only — your best, highest-priority cold-outreach targets.

Basic

Basic Protection

Strict authentication enforced — make sure your own SPF/DKIM/DMARC is clean before sending.

Enterprise

Enterprise Gateway

Dedicated SEG detected — throttle volume, lose link-heavy templates, and personalise hard.

Process

Clean Before Every Send

1

Verify the prospect

Check a single address inline or run your whole prospect list through the API or dashboard.

2

Drop the dead weight

Remove non-existent mailboxes, dead domains, disposables, and risky catch-alls from the send.

3

Segment & send

Route unprotected leads into high-volume sequences and gateway-protected ones into personalised outreach.

Use Cases

Built for Outreach Teams

SDRs & Sales

Spend touches on prospects that actually exist — and protect the team's sending domain.

Cold-Email Agencies

Keep client domains healthy across many campaigns by verifying every list before launch.

ABM Teams

Confirm target-account contacts are live and identify which sit behind enterprise gateways.

Founders & GTM

Run lean outbound without torching your domain reputation on a stale prospect list.

Pricing

Start Free — Scale With Your Outreach

100 free checks per day, no credit card required. Upgrade when your volume grows.

Free forever
$0 / month

Perfect for developers and small teams getting started with email validation.

  • 100 free checks per day
  • Single & bulk email validation
  • REST API access
  • Syntax, DNS, MX & mailbox checks
  • No credit card required
Get started free
Pay as you go
One-time purchase
$39

10,000 credits — use at your own pace. No subscription, no expiration.

Choose pack size
  • 10,000 verification credits
  • Credits never expire
  • Everything in the free plan
  • One-time payment — no recurring fees
  • $0.0039 per verification
Buy credits
High volume
Custom

For businesses and teams that need high-volume validation or dedicated infrastructure.

  • Unlimited or high-volume checks
  • Everything in the free plan
  • Priority support
  • SLA & dedicated infrastructure
  • Custom integrations & onboarding
Contact us
Questions?

Cold Email Verification FAQs

Work email addresses decay fast — people change jobs, companies retire mailboxes, and domains lapse. An address that was deliverable last quarter may bounce today. Re-verifying right before a send catches that decay so you are not burning sender reputation on addresses that no longer exist.
Every bounce signals to mailbox providers that you are sending to bad data, which drags down your sender score and pushes future mail toward spam. By removing non-existent mailboxes, dead domains, and disposable addresses before you send, MailRook Email Validation keeps your bounce rate low and your reputation intact.
MailRook Email Validation runs multi-level checks: syntax, domain and MX existence, SMTP mailbox verification, catch-all detection, disposable/throwaway detection, and role-account identification (info@, sales@). It also detects enterprise email security gateways so you can treat those prospects differently.
Yes. MailRook Email Validation detects 10 enterprise secure email gateways (SEGs) — including Proofpoint, Mimecast, and Barracuda — via MX analysis, and returns a protection level for every address. See the dedicated secure email gateway detection page for the full list and how to use it.
List cleaning is tuned for marketing lists and bulk hygiene. Cold email verification is streamlined for outreach: it leads with deliverability and the signals that matter before a cold send — mailbox existence, catch-all risk, role accounts, and gateway protection — so SDRs and agencies can prioritise who is actually worth contacting.
Yes. Every account gets 100 free checks per day — no credit card required — so you can verify prospects and test the API before scaling up.

Send to Real Inboxes Today

Verify your outreach list before the next send. 100 free checks per day, no credit card required.