The MailSure blog
Email verification, deliverability and clean lists
Practical guides for marketers and developers who want their email to reach real people.
The Black Friday email checklist: get your list ready
Peak-season sending magnifies list problems. A short checklist to run in the weeks before Black Friday so your best campaign days reach the inbox.
How to protect your free trial from abuse
Free trials attract people who sign up over and over. Practical ways to keep the offer generous for real users and unattractive to abusers.
CSV preparation tips before you verify a big list
A few minutes in a spreadsheet makes bulk verification smoother and cheaper. Common file problems and how to fix them.
Why a regex is not enough for email validation
A regular expression can check the shape of an address, and that is all. Here is what it misses, and what to do instead.
Understanding your results: valid, risky, invalid and unknown
What each Mailsure status means, what the score and reasons tell you, and what to do with every kind of result.
Email verification for e-commerce stores
Order confirmations, abandoned-cart emails and receipts all depend on a working address. Here is where verification pays off in a shop.
Sunset policies: when to stop emailing inactive subscribers
Subscribers who never open drag down your engagement and reputation. A sunset policy retires them kindly and protects your deliverability.
Email verification and privacy laws: POPIA, GDPR and what to keep in mind
Verifying addresses involves processing personal data. A plain-language overview of the points to consider. This is general information, not legal advice.
Verifying Gmail, Outlook and other big mailbox providers
Gmail and Hotmail/Outlook tell a verifier whether a mailbox exists. Company domains on Microsoft 365 and Google Workspace vary, and Yahoo and iCloud are cautious. Here is how each behaves.
How SMTP mailbox verification works (and its limits)
A verifier can ask a mail server whether a mailbox exists without sending an email. Here is the conversation, and why it isn't always conclusive.
What is sender reputation and how do you protect it?
Mailbox providers decide where your email lands based on your track record. Here is what goes into your reputation and how to build it.
How often should you clean your email list?
Lists decay constantly. Here is how to decide on a cleaning schedule based on how you collect and send, instead of guessing.
How to stop fake signups on your SaaS
Fake accounts waste your resources and distort your metrics. A layered approach works better than any single trick.
Real-time vs bulk email verification: which do you need?
Real-time checks stop bad addresses at the door. Bulk checks clean the list you already have. Most businesses need both, in different proportions.
How to add email validation to your signup form
A practical walkthrough of calling the Mailsure API from your server, handling each result and keeping the form friendly.
Double opt-in vs single opt-in: which should you use?
Double opt-in confirms every address is real and consented. Single opt-in is smoother. Here is the trade-off and a middle path.
How to warm up a new sending domain or IP
Mailbox providers don't trust unknown senders. Warming up means building volume gradually so they learn you are legitimate.
Gmail and Yahoo's bulk sender rules: what you need to do
Since 2024, Gmail and Yahoo require authentication, easy unsubscribes and low spam complaints from bulk senders. A practical checklist.
SPF, DKIM and DMARC in plain English
Three DNS records decide whether your email is trusted. What each one does, and how to check yours, without the jargon.
How MX records work (and why we check them)
MX records tell the world which servers accept mail for a domain. Checking them is the first real test of whether an address can receive email.
Typos in email addresses: the silent signup killer
A mistyped address means a lost customer who never knows why they didn't get your email. Here is how common typos are and how to catch them.
What are spam traps and how do they get onto your list?
Spam traps are addresses that exist to catch careless senders. Here are the types, how they end up on a list and how to stay clear of them.
Catch-all domains explained
A catch-all domain accepts mail for any address, real or not. That makes verification harder and these addresses riskier. Here is how to deal with them.
Role-based email addresses (info@, sales@): should you email them?
Role addresses reach a team, not a person. They are legitimate, but they behave differently from personal addresses. Here is how to handle them.
Disposable email addresses: what they are and how to block them
Throwaway inboxes let people sign up without giving you a real contact. Here is why they matter and how to deal with them sensibly.
How to clean your email list, step by step
A practical, ordered process for cleaning an email list: back up, deduplicate, verify, segment and keep it clean afterwards.
What is a good email bounce rate?
How bounce rate is calculated, what level is worth worrying about, and the quickest ways to bring it down.
How email bounces work: hard vs soft bounces
A bounce is a rejection notice from the receiving server. Hard and soft bounces mean very different things, and you should treat them differently.
Email validation vs email verification: is there a difference?
The two terms are used interchangeably, but there is a useful distinction. Here is how to think about it and which one you actually need.
What is email verification and why does it matter?
Email verification checks whether an address is real and can receive mail, before you send to it. Here is what it covers and what it can't do.