Result Codes TEXT CODE DESCRIPTION OK TO SEND? Valid Verified as a real address Yes (100% Secure) Invalid Verified as not valid (automatically removed) No Accept all (Unverifiable) A domain-wide setting (learn more) Maybe (Not recommended) Mailbox full Recipient inbox full error (automatically removed) No Disposable Temporary email account (automatically removed) No   Valid

What Is a Bounce Email? Hard Bounces vs. Soft Bounces Explained If you do any email marketing, “bounce” is a term you’ll run into fast — and the distinction between hard bounces and soft bounces trips up even experienced marketers. The good news is the difference is simple once it’s laid out clearly. Here’s what

What Is Greylisting? How It Works and Why It Matters Greylisting (also spelled graylisting) is one of the quietest but most effective tools mail servers use to fight spam. If you send email — or verify email lists — it’s worth understanding, because it directly affects both your delivery times and your verification results. Here’s

20 Best Email Testing Tools to Boost Deliverability in 2026 You spend hours writing copy and fine-tuning a template, then hit send and hope for the best. That last step is where campaigns quietly fall apart. An untested email can render badly in Outlook, land in the spam folder, bounce off invalid addresses, or look

What Is Email List Cleaning? Email list cleaning is the process of removing invalid, outdated, and unengaged addresses from your email marketing database. A clean list bounces less, lands in more inboxes, and earns better open and click rates — which is why regular cleaning is one of the simplest ways to protect your email

CSV is a (Comma Separated Value) file format utilized to store tabular data, such as a spreadsheet or database.  What makes a “good” CSV file as opposed to an “evil” one? Okay, I suppose evilness isn’t really a property of CSV files, but if you’ve ever wrestled with a bad one, I think you know

How to Choose the Right Email Verification Service for Your Business An email verification service checks every address in your database to confirm it’s real, deliverable, and safe to send to. Run your list through one and it separates the dead and risky addresses from the active ones, so your campaigns reach actual customers instead

What Is a Role-Based Email Account? A role-based email account is tied to a function or department rather than a specific person. Addresses like sales@, admin@, support@, and info@ are the classic examples — they’re managed by whoever happens to hold that role, and often by several people at once. As you build an email

How to Verify a Hotmail, Outlook, MSN, or ProtonMail Email Address Can you verify a Hotmail, Outlook, MSN, or ProtonMail email address before adding it to a campaign? Yes — but these providers are trickier to check than Gmail, and a lot of verification tools quietly get them wrong. Below is how the process actually