Email Marketing Glossary

A method of comparing two versions of an email (e.g. different subject lines) to see which performs better. Half of your subscribers receive version A, the other half version B, and you measure which gets more opens or clicks.

A list maintained by email providers or anti-spam organizations that blocks emails from known spam senders. If your sending IP or domain ends up on a blocklist, your emails may not reach inboxes. Good deliverability practices help you stay off these lists.

The percentage of sent emails that could not be delivered. Bounces are divided into hard bounces (permanent) and soft bounces (temporary). A high bounce rate hurts your sender reputation.

A button or link in your email that encourages the reader to take a specific action, such as "Shop now", "Read more", or "Book a table". Strong CTAs are clear, visible, and action-oriented. Learn more in our guide to better emails.

A US law (Controlling the Assault of Non-Solicited Pornography And Marketing Act) that sets rules for commercial emails. It requires a physical mailing address, a clear unsubscribe option, and honest subject lines.

The percentage of email recipients who clicked on one or more links in your email. Calculated as (clicks / delivered emails) x 100. A good CTR varies by industry but typically ranges from 2-5%. See our click tracking guide for more.

A collection of email addresses and subscriber information stored in your email marketing platform. Good list management means keeping your contacts organized and up to date. Learn how to grow your email list.

The ability of your emails to reach recipients' inboxes rather than being filtered to spam or blocked entirely. Deliverability depends on sender reputation, authentication (SPF, DKIM, DMARC), and content quality. Read our guide to avoiding the spam folder.

An email authentication method that adds a digital signature to your emails, allowing the receiving server to verify they were actually sent by your domain and were not tampered with in transit. See our authentication guide.

An email authentication protocol that builds on SPF and DKIM. It tells receiving mail servers what to do when an email fails authentication checks: do nothing, quarantine it, or reject it. Read about setting up DMARC.

A single email or series of emails sent to a group of subscribers with a specific purpose, such as promoting a sale, sharing news, or welcoming new customers.

A unit used by some email marketing platforms (including Minutemailer) to measure sending volume. One credit typically equals one sent email. Learn more about how credits work.

How often you send emails to your subscribers. Finding the right frequency is key: too many emails can lead to unsubscribes, while too few can cause your audience to forget you. Check our guide on the best time to send newsletters.

A collection of email addresses from people who have given you permission to send them emails. Building a quality email list is the foundation of successful email marketing. Here is how to grow your list.

A pre-designed email layout that you can customize with your own content, images, and branding. Templates save time and help maintain a consistent look across your campaigns.

A metric that measures how actively your subscribers interact with your emails, typically combining opens, clicks, and other actions. Higher engagement signals to email providers that your emails are wanted.

A European Union regulation that governs how personal data (including email addresses) is collected, stored, and used. For email marketing, GDPR requires explicit consent before sending marketing emails to EU residents.

A permanent delivery failure, usually because the email address does not exist or the domain is invalid. Hard bounces should be removed from your list immediately to protect your sender reputation.

An email that uses HTML code to include formatting, images, colors, and layout. Most marketing emails are HTML emails. Compare with plain text email.

The practice of dividing your email list into smaller groups based on shared characteristics, such as location, purchase history, or interests. Segmented emails tend to get higher open and click rates because the content is more relevant.

Placeholder codes in your email template that are automatically replaced with subscriber-specific data when the email is sent. For example, {{first_name}} would be replaced with each recipient's first name.

A regularly sent email to subscribers that shares news, updates, tips, or content. Newsletters are one of the most common forms of email marketing for small businesses. Learn how to start a newsletter.

The percentage of delivered emails that were opened by recipients. Calculated as (unique opens / delivered emails) x 100. Average open rates vary by industry but typically range from 15-25%.

The process by which someone agrees to receive your emails. Single opt-in means they sign up and are immediately added. Double opt-in adds a confirmation step where they must click a link in a verification email. Double opt-in leads to higher quality lists.

Customizing email content for individual subscribers using data like their name, location, or past behavior. Even simple personalization like using a first name in the subject line can improve open rates.

An email without any formatting, images, or HTML. Plain text emails can feel more personal and sometimes achieve better deliverability, but they lack visual design elements.

The short summary text that follows the subject line in an email inbox preview. It gives recipients a second reason to open your email. A well-written preheader can significantly boost open rates.

An email specifically designed to promote a product, service, sale, or event. Promotional emails are marketing messages and require recipient consent.

A targeted email or series of emails sent to inactive subscribers to encourage them to interact with your emails again. Often includes special offers or a simple "Do you still want to hear from us?" message.

An email designed to automatically adjust its layout and formatting to look good on any screen size, from desktop to mobile. With over 60% of emails opened on mobile, responsive design is essential.

A score assigned to your sending domain or IP address by email providers, based on factors like bounce rates, spam complaints, and engagement. A good reputation means your emails are more likely to reach inboxes.

A temporary delivery failure, often caused by a full inbox, a server being temporarily unavailable, or a message being too large. Soft bounces may resolve on their own, but repeated soft bounces to the same address should be investigated.

Software used by email providers to detect and block unwanted or harmful emails. Spam filters analyze content, sender reputation, and authentication to decide whether an email reaches the inbox. Follow our tips to avoid spam filters.

An email authentication method that lets domain owners specify which mail servers are authorized to send emails on their behalf. SPF records are published in your domain's DNS settings. See our authentication guide.

The title of your email that appears in the recipient's inbox. It is the single most important factor in whether someone opens your email. Good subject lines are concise, relevant, and create curiosity.

A person who has opted in to receive your emails. Subscribers are the foundation of your email marketing, and treating them well with relevant, valuable content keeps them engaged.

An email triggered by a specific action, such as a purchase confirmation, password reset, or shipping notification. Transactional emails are not marketing messages and usually do not require marketing consent.

The percentage of recipients who opt out of your email list after receiving an email. Calculated as (unsubscribes / delivered emails) x 100. A rate above 0.5% per email may indicate issues with content relevance or sending frequency.

An approved list of senders whose emails are allowed through spam filters. Asking subscribers to add your email address to their contacts or whitelist improves deliverability.

An email sent to customers who have not engaged or purchased in a while, aimed at re-activating them. Often includes incentives like discounts or reminders of what they are missing. Read about getting repeat customers with email.