What VerifyFlow Actually Checks

Not just a yes/no. Every address in your list goes through three checks, and every result tells you exactly why it landed where it did.

The three checks

01

Format

Every address is checked against proper email syntax before anything else, catching typos, stray characters, and malformed addresses instantly.

02

Domain & MX records

We confirm the domain after the @ actually exists and is set up to receive mail. No mail server means no delivery, no matter how the address is spelled.

03

Mailbox existence

Where it can be determined without sending an email, we check whether the specific mailbox is live: the difference between "the domain works" and "this address works."

What you get back

You get the same file back (same rows, same columns) with a status added to every address. Addresses come back VALID or INVALID, and invalid addresses carry a specific reason so you know what to do next:

  • Bad format
  • No mail server (MX record missing)
  • Mailbox not found
  • Disposable or throwaway domain
  • Role account (e.g. info@, support@)
  • Catch-all domain (accepts anything)

File handling & limits

Upload a CSV or Excel (.xlsx) file with up to 1,000,000 rows. We auto-detect which column holds the email addresses, so it doesn't need to be first or specifically named.

Large files upload directly into storage rather than through a single request, then get split into small chunks behind the scenes, each verified independently, in parallel. That's what makes a million-row list practical instead of something that times out.

One flat price, no matter the size

£20 covers one list, up to a million rows. No subscription, no account, no per-row pricing that punishes you for having a big list.