Email Verification Glossary
Clear definitions for the terms that matter in email verification and deliverability. From SMTP checks and catch-all domains to SPF, DKIM, DMARC, and spam traps, this glossary explains the 40 concepts behind clean lists and reliable inbox placement.
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Email Authentication
Email Authentication
The set of standards mailbox providers use to confirm a sender is genuine
SPF (Sender Policy Framework)
A DNS record that lists which servers are allowed to send for your domain
DKIM (DomainKeys Identified Mail)
A cryptographic signature that proves a message was not altered in transit
DMARC
A policy that tells receivers what to do when SPF or DKIM checks fail
BIMI
A standard that displays your verified brand logo next to authenticated mail
ARC (Authenticated Received Chain)
A header chain that preserves authentication results when mail is forwarded
Return-Path
The hidden address where bounce messages and delivery errors are sent
DNS Validation
Checking a domain's DNS records to confirm it can receive email
Deliverability
Email Deliverability
How reliably your messages reach the inbox instead of spam or rejection
Sender Reputation
The trust score mailbox providers assign to your sending domain and IP
Inbox Placement
The share of sent mail that lands in the inbox rather than the spam folder
Email Blacklist
A database of senders flagged for spam that providers use to block mail
Email Warmup
Gradually ramping up volume on a new domain to build sending trust
Email Throttling
Limiting how fast you send so mailbox providers do not rate-limit you
Greylisting
A spam defense that temporarily defers mail from unknown senders
Feedback Loop
A provider report that tells you which recipients marked you as spam
Seed List
A set of test inboxes used to check where your campaigns land
Verification Concepts
Email Verification
Confirming an address is real and able to receive mail before you send
SMTP Verification
Querying the mail server directly to check if a mailbox exists
Real-time Verification
Checking an address the instant it is entered, such as at signup
Bulk Verification
Validating an entire list of addresses in one batch upload
Validation vs Verification
The difference between checking format and confirming a mailbox is live
Catch-all Domain
A domain that accepts mail to any address, making results hard to confirm
MX Record
The DNS entry that names which servers handle a domain's incoming mail
Email Finder
A tool that locates a person's likely work email from name and company
Email Appending
Matching existing customer records to add missing email addresses
List Health
Email List Hygiene
The ongoing practice of removing invalid and inactive contacts
Bounce Rate
The percentage of sent emails that could not be delivered
Hard Bounce vs Soft Bounce
Permanent delivery failures versus temporary ones you can retry
List Decay
The natural rate at which email addresses on a list go stale each year
Suppression List
Addresses you exclude from sends, such as unsubscribes and bounces
Engagement Scoring
Ranking contacts by opens and clicks to focus on active subscribers
Role-based Email
Shared addresses like info@ or sales@ that often hurt deliverability
Double Opt-in
Requiring subscribers to confirm via email before joining a list
Risk & Compliance
Spam Traps
Hidden addresses used to catch senders with poor list practices
Disposable Email
Temporary addresses that expire and damage list quality
Honeypot Email
A planted address designed to flag bots and scraped lists
CAN-SPAM Act
The US law setting rules for commercial email and opt-outs
GDPR and Email
How EU privacy law governs consent for email marketing
CCPA and Email
How California privacy law affects collecting and using email data
Put It Into Practice
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