Bulk email verification

Verify a list. No email platform required.

Drop a CSV, paste a list, or use one of our extensions. mailfloss returns a clean file in minutes — and you pay only for what you verify. No subscription, no integration, no setup.

Credits never expirePer-email pricingSame engine as our subscription

Upload list

CSV · 12,847 rows

Drag a CSV here

or paste a list · CSV, TSV, XLS, XLSX, TXT

Pick how you want to verify

Four ways. Zero ESP integration.

Upload a CSV

Drag and drop a file of any size. mailfloss processes it in minutes and returns a cleaned file with verification results per row.

Copy & paste

Paste 1 to 100,000 addresses directly into the mailfloss dashboard. Results stream back as we work — watch them tick in real-time.

Google Sheets

Install our Sheets add-on. Verify any email cell in place — the result shows up in the next column. No exports, no re-imports.

Airtable

Same idea, inside Airtable. Add a verification field to any base and watch the rows clean themselves.

How CSV upload works

Drop a file. Get a cleaner one back.

Watch a sample list of 12,847 addresses get verified in real-time. Same engine that powers every other mailfloss product, exposed as a one-time job.

Upload list

CSV · 12,847 rows

Drag a CSV here

or paste a list · CSV, TSV, XLS, XLSX, TXT

What you get back

A clean file. And the receipts.

Every row in your CSV gets a verification result, a status, and a reason. Re-import only the addresses you trust.

76%

Valid

Real, deliverable inboxes. Keep these.

Typo corrected

mailfloss fixed the domain in place. Keep these.

Risky / catch-all

Deliverable but uncertain. Decide per-row.

Invalid

Bounced or malformed. Don’t send to these.

Disposable / role

Mailinator, role accounts, etc. Skip.

Plus every other column you uploaded — free.

If your CSV has name, company, country, or any other columns, mailfloss returns them untouched alongside the verification results. No re-merging, no row mismatch, no extra cost.

List-verify FAQ

Common questions.

No. Prepaid credits work without a subscription. Upload a list, pay for the credits you use, done. If you later decide you want continuous cleanup, you can connect your email platform and switch to a subscription anytime.

Building something?

mailfloss has a developer side, too.

Not cleaning a one-off list? These run the same verification engine — wired into your code or your signup forms.

Verification API & webhooks

Single + bulk REST endpoints, plus webhooks that fire the moment an address is verified, fixed, or removed.

Read the API docs

JS form widget

Drop a snippet on any opt-in form to block typos, fakes, and disposables before the form submits.

How the widget works

No code? No problem.

Automate it with Zapier.

Connect mailfloss to 6,000+ apps and verify every email as it moves through your stack — no developer required. Build it once in Zapier and let it run in the background.

Verify lead-ad emails

When a Facebook or LinkedIn Lead Ad comes in, verify the address before it reaches your CRM or your sales team.

Clean your CRM on create

New Pipedrive or Salesforce contact? Verify it the moment it lands, then tag or drop the bad ones automatically.

Guard billing & support

Filter invalid and disposable addresses before they hit Stripe, Intercom, or your helpdesk.

Connect via Zapier

Ready when you are

Stop paying to email a leaky list.

Connect your email platform in 30 seconds. mailfloss starts catching typos and cleaning your list on autopilot.

Free 7-day trialEasy setupMoney-back guarantee