What is a catch-all email?
Why some domains accept every address, how verifiers detect them, and why they can't be confirmed.
GlossaryHard bounce vs soft bounce
Permanent vs temporary failures, the SMTP codes behind each, and what to do with them.
GlossaryRole-based email addresses
info@, sales@, support@: why shared inboxes are flagged risky, and when to email them anyway.
GlossarySpam traps
The three kinds of trap, how lists pick them up, and what verification can and can't do about them.
GlossaryVerification vs validation
Two words for overlapping things. What each usually means, and which checks actually stop bounces.
GlossaryEmail verification statuses
Deliverable, risky, undeliverable and unknown: every result and reason, and what to do with each.
GlossaryEmail bounce codes
A plain-English table of SMTP reply codes and enhanced status codes, and what to do about each.
GlossaryVerify an email without sending
The manual MX lookup and SMTP walkthrough, and why it often fails from a home connection.
GlossaryWhat is SPF?
SPF lists which servers may send mail for your domain. Syntax, an example record and the 10-lookup limit.
GlossaryWhat is DKIM?
DKIM signs each message so receivers can prove it came from your domain. Selectors, keys and a sample record.
GlossaryWhat is DMARC?
DMARC tells receivers what to do when mail fails SPF and DKIM. Policies, alignment and a starter record.
GlossaryWhat is an MX record?
MX records tell the internet which servers receive a domain's mail. Priorities, an example and how verifiers use them.
GlossaryWhat is greylisting?
Greylisting temporarily rejects mail from unknown senders. How it works and how it affects verification.
Email providersIs Gmail a catch-all?
How consumer Gmail (gmail.com) answers an address check and what result to expect.
Email providersIs Google Workspace a catch-all?
Workspace domains are catch-all only when an admin sets a routing rule. What that looks like when verifying.
Email providersIs Microsoft 365 a catch-all?
Authoritative vs internal-relay domains in Exchange Online, and why Microsoft addresses often return unknown.
Email providersIs Outlook.com a catch-all?
Consumer Outlook.com, Hotmail and Live addresses: what is and isn't documented, and the results to expect.
Email providersIs Yahoo Mail a catch-all?
Yahoo Mail addresses and bounce behaviour: what Yahoo documents and what you'll see when verifying.
Email providersIs iCloud Mail a catch-all?
icloud.com addresses vs custom domains on iCloud+, where an owner can switch on catch-all.
Email providersIs Zoho Mail a catch-all?
Zoho Mail domains are catch-all only if the admin sets a catch-all address.
Email providersIs Proton Mail a catch-all?
proton.me addresses vs custom domains on a paid Proton plan with a catch-all address.
DeliverabilityWhat is a DNSBL?
How DNS black hole lists work, what gets a sender listed and how verification keeps you off them.
LearnEmail bounce rate explained
How bounce rate is calculated, what's a good number, and why tools disagree on the formula.
LearnWhat is email verification?
The six checks behind a verification, what the results mean and when to run it.
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