GuidesList hygiene
Keep a contact ID in your verification file
A simple export makes it easier to return each result to the right contact without exposing your whole CRM.
·1 min read
Blog
Practical notes on email verification, deliverability and list hygiene, from the team that runs MailOK.
APIGuides
Before you connect an email verification API
Plan for unresolved checks, failed requests and changing addresses before putting verification into production.
·1 min read
VerificationTechnical
Why the last few addresses can take longer
A verification job can slow down near the end because some receiving servers need more time or give no clear answer.
·1 min read
PrivacyGuides
Before you upload your contact list
Send only what the check needs, and get specific answers about retention, deletion and reuse.
·1 min read
Verification
Before you guess someone’s email address
A plausible naming pattern and a positive server response do not establish who will receive your message.
·1 min read
Deliverability
The addresses work. Why is the email going to spam?
Check authentication, recipient expectations and delivery reports before paying to clean the list again.
·1 min read
List hygieneDeliverability
Before you email that old list
A dormant list needs a review of addresses, subscription history and whether the message still makes sense.
·1 min read
SignupsList hygiene
Ask before you fix an email typo
A useful suggestion can save a signup. An automatic correction can send mail to the wrong person.
·1 min read
List hygieneDeliverability
Before you remove everyone who never opens
Open tracking can mislead you. Review other activity before deciding a subscriber has gone quiet.
·1 min read
Deliverability
A working address can still be a spam trap
Why verification cannot certify a list as trap-free, and what to change when trap problems appear.
·1 min read
List hygieneSignups
Should you block disposable email addresses?
Decide based on what the account needs, and distinguish temporary inboxes from lasting privacy aliases.
·1 min read
VerificationTechnical
What an SMTP check actually tells you
A server response provides evidence about delivery, but it cannot confirm everything about a mailbox.
·1 min read
APIGuides
Check the address while the person can still fix it
Catch obvious mistakes at signup, allow for inconclusive checks, and confirm inbox access separately.
·1 min read
List hygiene
Keep the invoice going to accounts@
A role address describes a purpose. It does not, by itself, tell you to remove the contact.
·1 min read
VerificationDeliverability
What a catch-all result leaves unanswered
The server accepts the address. That still may not tell you whether the intended mailbox exists.
·1 min read
List hygieneGuides
You inherited a mailing list. Start here.
Check its source, preserve exclusions, verify the addresses, and put the results back where they will be used.
·2 min read
DeliverabilityBounces
Read the bounce reason before you clean the list
A bad address, a temporary delay and a policy block need different fixes.
·1 min read
PricingVerification
Why unknown results are free
An unresolved check should remain unresolved, and MailOK does not charge for that result.
·1 min read
VerificationGuides
Valid, invalid, risky, unknown: what to do next
Read verification results as evidence about an address, with the reason and check date attached.
·1 min read
Product
What you can use MailOK for
Check a contact list before a send, or check new addresses as they enter your product.
·1 min read
Check a list before your next campaign
Upload a CSV or Excel file and get a verdict on every address. 100 free credits, no card needed.
Start for free