Email Terminology Explained
Learn the key terms and concepts in email verification, deliverability, and email marketing. 32 terms to master.
Bounce
When an email cannot be delivered to the recipient's address. Bounces are categorized as "hard" (permanent failure like non-existent address) or "soft" (temporary failure like full inbox).
Bounce Rate
The percentage of emails that fail to deliver to the recipient's inbox. A healthy bounce rate is typically under 2%. Higher rates can damage sender reputation and trigger spam filters.
Disposable Email
A temporary email address created for short-term use, typically expiring after minutes or hours. Services like Guerrilla Mail, 10 Minute Mail, and Mailinator provide these addresses. Disposable emails should be blocked as they have zero long-term value.
DKIM (DomainKeys Identified Mail)
An email authentication method that adds a cryptographic signature to outgoing emails, allowing receiving servers to verify the message hasn't been altered in transit and was sent by an authorized sender.
DMARC (Domain-based Message Authentication)
An email authentication policy that tells receiving servers what to do when SPF or DKIM checks fail. DMARC helps protect your domain from being used in phishing attacks and provides visibility into email authentication failures.
Double Opt-In
A subscription method requiring new subscribers to confirm their email address before being added to your list. The subscriber enters their email, receives a confirmation email, and must click a link to verify. This ensures list quality and consent.
Email Authentication
The collection of protocols (SPF, DKIM, DMARC) used to verify that an email actually came from the claimed sender. Proper authentication is now required by major email providers like Gmail and Yahoo for reliable inbox delivery.
Email Campaign
A coordinated set of email messages sent to achieve a specific goal, such as promotions, newsletters, or re-engagement. Campaign success is measured by open rates, click rates, and conversions.
Email Deliverability
The ability of an email to successfully reach the recipient's inbox rather than being filtered to spam or rejected entirely. Deliverability depends on sender reputation, authentication (SPF, DKIM, DMARC), content quality, and list hygiene.
Email Hygiene
The practice of maintaining a clean email list by removing invalid, inactive, and risky addresses regularly. Good hygiene improves deliverability and protects sender reputation.
Email Validation
Checking an email address for proper syntax, format, and basic structure. Usually the first step in email verification before DNS and SMTP checks.
Email Verification
The complete process of validating whether an email address is real, properly formatted, and can receive messages. Verification typically includes syntax checking, domain/MX validation, SMTP verification, and checks for disposable or role-based addresses.
Email Warm-Up
The process of gradually increasing email sending volume on a new IP address or domain to build sender reputation. Starting with large volumes immediately can trigger spam filters—instead, slowly scale up over weeks while maintaining high engagement.
Safe Sender
An email sender that recipients have explicitly marked as trusted, ensuring their emails bypass spam filters and land in the primary inbox.
Sender Reputation
A score assigned to your sending domain and IP address by email service providers (Gmail, Yahoo, Outlook) that determines whether your emails reach the inbox or spam folder. It's influenced by bounce rates, spam complaints, engagement rates, and authentication.
Sender Score
A numerical measurement (0-100) of your email sending reputation, provided by services like Return Path. Used by ISPs to decide whether to accept or filter your emails.
SMTP Verification
A method of validating email addresses by connecting to the recipient's mail server and simulating the email sending process without actually delivering a message. This is the most accurate way to verify if a mailbox exists and can receive mail.
Soft Bounce
A temporary email delivery failure caused by issues like a full mailbox, server downtime, or message size limits. Soft bounces may become deliverable later, but repeated soft bounces to the same address should be investigated.
Spam Trap
An email address used by ISPs and anti-spam organizations to identify senders with poor list practices. Pristine spam traps are addresses that never opted in, while recycled spam traps are old, abandoned addresses. Hitting spam traps severely damages sender reputation.
SPF (Sender Policy Framework)
An email authentication protocol that specifies which mail servers are authorized to send email on behalf of your domain. SPF helps prevent email spoofing and is checked by receiving servers to verify the sender.
Suppression List
A list of email addresses that should not receive emails. Includes unsubscribes, complainers, hard bounces, and known invalid addresses. Essential for maintaining compliance and sender reputation.
Valid Email
An email address that has proper syntax, belongs to an existing domain with MX records, and has a verified mailbox that can receive messages.
Verification Result
The outcome of an email verification check. Common results include valid, invalid, disposable, role-based, catch-all, and unknown. Each result type requires different handling strategies.
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