Built for newsletter and subscription teams

Email Verification for Media & Publishing

A subscriber count is only useful if it is real.

Newsletter signup forms are open to the whole internet, which means they collect bots, typos and throwaway addresses alongside genuine readers. Those addresses inflate the number you report, cost you money on every send, and quietly damage the deliverability of the ones that matter.

Start with 100 free credits View pricing

10M+ verifications · 99.5% accuracy · 4.9/5 rated · No credit card required

What we found in 807,203 verifications · H1 2026

75.9%

Deliverable

10.2%

Invalid

8.7%

Risky

8.1%

Catch-all

80% of the lists we processed were at least 20% unusable. See the full benchmark data

Why publishers verify at the signup form

For a newsletter business, list size is the product metric and deliverability is the delivery mechanism. Unverified signups damage both at once.

Keep bot signups out of the list

Open signup forms attract automated submissions. Real-time verification rejects them before they ever count as a subscriber.

Report numbers you can stand behind

If advertisers or investors are looking at subscriber counts, those counts should reflect people who can actually receive the newsletter.

Stop paying to send to dead addresses

Most ESPs bill on list size or send volume. Every undeliverable address on the list is a line item with no possible return.

Protect the sender reputation the newsletter depends on

High bounce rates push a newsletter from the inbox into promotions and then into spam, taking your engaged readers with it.

Catch typos on paywall and registration flows

A reader who mistypes their address at signup never gets the confirmation, and often never tries again.

Scale with the audience, not with a plan tier

Pay-as-you-go from $4 per 1,000 emails, credits never expire, and a viral week does not force a plan upgrade.

Verify the subscriber before they count as one

Put a verification call in the newsletter signup handler. Invalid and disposable addresses are turned away at the form, so your list and your reported numbers only ever contain real readers.

Rejects disposable domains used to get past a registration wall

Catches the typo before the double opt-in email is sent to nowhere

Works across every brand and property you publish under

Read the API documentation

Node.js

// routes/subscribe.js
const v = await fetch(
  'https://clearbounce.net/api/v1/verify?email=' + email,
  { headers: { 'X-API-Key': process.env.CB_KEY } }
).then(r => r.json());

if (v.result === 'undeliverable' || v.is_disposable) {
  return res.status(422).json({
    message: 'Please enter an address that can receive the newsletter.'
  });
}

await esp.addSubscriber(email);   // only real readers get counted

Find out what your list is really worth

Most publisher lists were built over years, through competitions, content downloads and open signup forms. Verifying the whole file tells you how many of those subscribers can still be reached, which is the number that actually matters.

Connect Mailchimp, Beehiiv-style exports or any CSV from your ESP

See exactly how much of the list is undeliverable, risky or catch-all

Suppress the dead addresses before your next billing cycle

When a publisher needs to verify immediately

Each of these is a point where an unverified list turns into a measurable cost.

Signups jumped and you cannot explain it

A sudden spike is either a successful piece of content or a bot filling your form. Verification results tell you which within minutes.

You are reporting subscriber numbers to advertisers

Rate cards are built on audience size. Numbers that include undeliverable addresses are numbers you would rather not have to defend.

Newsletter open rates are drifting down

A slow decline across every issue usually means the list is decaying rather than the content failing.

Your ESP bill is growing faster than the audience

If you are billed on list size, dead addresses are a direct monthly cost. Cleaning the list shows up on the next invoice.

You are launching a new title or vertical

A fresh sending domain has no reputation to spare, so the first send needs to go to a list that is known to be clean.

A competition or giveaway just closed

Prize-driven signups attract throwaway addresses in volume. Verify before those entries are merged into the main list.

Works with the tools you already send from

Connect your platform and verify the list where it already lives, or use the API and skip the export entirely.

See all integrations

Pay for what you verify, keep what you do not use

Verification demand is rarely flat. It spikes when you migrate, when a season starts, when a list arrives. Pricing that assumes a steady monthly volume charges you for the quiet months too.

Credits never expire. Buy for the spike, use the balance whenever it comes up next.

From $4 per 1,000 emails pay-as-you-go, or save 20% on a subscription if your volume is predictable.

100 free credits on signup, no credit card required.

Start free

100 credits

Enough to verify a real sample of your list and see the result breakdown before you spend anything.

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Questions media and publishing teams ask

Will verification block real readers from subscribing?

Only addresses that come back as undeliverable are rejected, meaning the mailbox does not exist or the domain cannot receive mail. A genuine reader with a working address is never turned away.

Can I verify signups across several brands or titles?

Yes. A single API key and credit balance covers every property you publish, rather than requiring separate accounts per title.

How does this work with double opt-in?

They solve different problems and work well together. Verification stops the confirmation email being sent to an address that cannot receive it in the first place, which is where most double opt-in flows silently fail.

What should I do with catch-all subscribers?

Catch-all domains accept mail for any address, so their status cannot be confirmed by anyone. Most publishers keep them in a lower-frequency segment and watch engagement rather than removing them outright.

How often should a newsletter list be verified?

Verify at the signup form continuously, and re-verify the full list every three to six months. Publisher lists decay quickly because signup forms are open to everyone.

Related reading: Disposable email addresses explained What to do with catch-all addresses

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