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Email deliverability dictionary
Email deliverability dictionary

Glossary with common terms related to email deliverability

Ilona Srebnicka avatar
Written by Ilona Srebnicka
Updated over a week ago

The following glossary defines basic acronyms and terms used in edrone, as well as in the e-commerce industry.


  • Audience - the group of recipients of a particular message, campaign.

  • Autoresponder - a tool in email marketing that automatically sends predefined emails to recipients at a specific time or in response to specific actions.


  • Blacklist - a collection of email addresses, domains, IP numbers or other identifiers that are considered undesirable or spammy. Organizations create and maintain blacklists to block, flag or restrict access to resources, such as email inboxes or access to servers, for entries on these lists.


  • Campaign (newsletter) - a single, one-off mailing to a predefined group of contacts.

  • CNAME (Canonical Name) - a type of DNS record that is used to create an alias or redirect for a particular domain to another domain address. The CNAME record is used to facilitate access to online resources under different names.

  • CTA (Call-to-Action) - a clear call to action, usually in the form of a button, link or other form, which is intended to prompt the user to take a specific action, such as making a purchase, signing up, downloading a file or simply clicking on a link.

  • CTOR (Click-To-Open Rate) - this is a metric used in email marketing that measures the percentage of clicks on links contained in an email message relative to the number of opens.

  • CTR (Click-Through Rate) - this is a metric used in online marketing that measures the percentage of clicks on an ad, link or interactive element relative to the number of impressions (the number of clicks divided by the number of impressions, multiplied by 100).


  • Data controller - the entity that is responsible for determining the purposes and means of processing personal data. In the context of data protection legislation, such as the European General Data Protection Regulation (GDPR), the term "controller" is of key importance. When using external services, the controller is also obliged to select data processors with attention to their ability to meet data protection requirements.

  • Data Operator - refers to an entity that processes personal data on behalf of a data controller. In the context of data protection legislation, such as the GDPR, the term is used to describe the role of an entity that performs the specific work of processing personal data, but does not decide on the purposes and means of that processing.

  • Dedicated IP - a unique IP address assigned to one sender or one company to send its emails. Unlike shared IPs, which are used by many different senders, dedicated IPs are only assigned to one entity.

  • Deliverability - the effective delivery of emails to inboxes without rejections, delays or being placed in the spam folder.

  • DKIM (Domain Keys Identified Mail) - an email authentication standard that helps verify that a particular email is from the actual sender, and it has not been forged in transit and no one is impersonating the sender.

  • DMARC (Domain-based Message Authentication, Reporting, and Conformance) - an email security standard that helps protect against email forgery and phishing. It establishes a domain authentication policy, providing email senders and recipients with greater security, and enables reporting of attempted fraud.

  • DNS (Domain Name System) - a hierarchical system that converts human-readable domain names, such as, into IP addresses, which are numerical identifiers used by computers to find and connect to each other on the network. DNS acts as a directory that helps browsers and other applications find the actual servers hosting websites or services associated with specific domain names.

  • Double opt-in (also referred to as 'confirmed opt-in' or 'double confirmation') - a type of process for obtaining consent from a user to subscribe to a service, receive marketing communications or use a particular service by confirming twice. In the context of an e-mail subscription, a person enters their e-mail address e.g. in a subscription form, e.g. by clicking a button, and then receives a message with a button or link and a request for a second confirmation. Only after the second confirmation the subscriber is added to the list.


  • ESP (email service provider) - a service or platform that can send commercial and transactional emails on your behalf.


  • Product feed - a list of products and information about them, generated directly from the platform in the form of a dynamic link in XML format

  • From - is a field in the e-mail header that indicates the e-mail address of the sender. The recipient of the email sees this address as information of who the author or sender of the email is.


  • Hard bounce - occurs when an email cannot be delivered for a persistent reason, e.g. the email address is invalid, does not exist, has been deactivated or the recipient's domain is blocked.

  • Hosting - a service provided by hosting companies, which involves providing the server resources and infrastructure needed to store data and allow access to it via the Internet. A hosting service allows companies, organizations and individuals to host their websites, applications, databases, media files and other resources online so that they can be accessed by users on the web.

  • Hygienization - practice of maintaining the cleanliness and quality of a subscriber list. This process involves removing inactive, invalid or non-existent email addresses from the subscriber list, which helps to maintain a high quality email database. Subscriber list hygiene is a key part of ensuring email deliverability.


  • IP - a unique sequence of numbers (separated by dots) that identifies a device or server on the Internet.

  • IP warming - the process of gradually increasing the volume of emails sent from a newly activated IP address in order to build and maintain a good reputation for that address in the eyes of email service providers. This is particularly important for new senders or those starting to use new IP addresses to send large numbers of emails.

  • ISP (Internet Service Provider) - an internet service provider, it provides the infrastructure that allows users to connect to the internet, upload and download data, use email, browse the web, and other online services.


  • Landing page - a specially designed website that a user arrives at after clicking on a link, advertisement, or other form of entry. The purpose of an LP is usually to draw the user's attention to a specific goal, such as buying a product, signing up for a newsletter, downloading a file, taking a survey or performing another action.


  • Mailing database - also known as a mailing list or subscriber list, is a collection of email addresses and sometimes other contact information of people who have agreed to receive emails from a particular sender. Mailing databases are used for email marketing activities, i.e. sending targeted messages to promote products, services, inform about news or maintain customer relationships.

  • Marketing consent - the voluntary and unambiguous consent given by a person or entity to receive marketing communications such as emails, text messages, calls, pushes etc. from a specific sender. This consent is a key element of privacy and data protection compliance, especially in the context of regulations such as GDPR (the Data Protection Regulation) in the European Union.

  • Marketing message - a message or information sent to promote products, services or a brand. Its purpose is to attract the attention of potential customers, build brand awareness and customer relationships, and encourage specific actions such as purchasing a product, using a service, subscribing to a newsletter or participating in a promotion.

  • MX (Mail Exchange) - a type of DNS record that points to the mail server responsible for receiving emails for a specific domain. The MX record is crucial in the process of routing email traffic across the internet.


  • Newsletter - is a form of electronic communication, usually in the form of an email, regularly sent to subscribers to provide information, news, promotions or other content, as well as to keep in touch with recipients, build relationships, promote products or services and news.


  • Opt-in - the process of obtaining consent from a user before adding them to a subscriber list or sending them marketing communications. In the context of marketing, opt-in means that a person has voluntarily agreed to receive certain information, offers or communications from a particular sender. This is compliance with the principle of voluntariness in terms of privacy and the processing of personal data.

  • OR (open rate) - an indicator that measures the percentage of people who have opened (i.e. read) specific emails in relation to the total number of delivered emails. It is an important indicator in analyzing the effectiveness of an email marketing campaign and allows us to assess how well recipients are responding to the messages sent.


  • Phishing - a form of cyber-attack in which an attacker impersonates a trusted source, such as a financial institution, company or website, in order to deceive users and obtain sensitive information from them, such as passwords, financial data or personal information. Phishing attacks most commonly use email, but can also involve other forms of communication such as text messages (SMS), instant messaging or social media.


  • Reputation (of domain/IP) - a measure that assesses how positively or negatively e-mails originating from a specific domain or IP address of the sender are received. It is a key factor affecting email deliverability, i.e. the ability of messages to reach inboxes.

  • Return_path - an email header that specifies the email address to which the email system should send return notifications (bounces) regarding delivery errors. This address is usually hidden from message recipients and is used to communicate delivery problems, such as incorrect email addresses, full mailboxes, or other obstacles preventing the message from being delivered to the recipient.


  • Scenario (automation) - a tool in the edrone system used to send automatic messages after specific actions by website users.

  • Segmentation - the process of dividing recipients into smaller, defined segments/groups. The purpose of segmentation is to better adapt the offer to the needs, preferences and characteristics of different customer groups. It is important in creating marketing strategies and allows focusing activities on specific groups of recipients.

  • Sender - in the context of email marketing and electronic communications, refers to the person, company or organization that sends an email message to recipients. The sender is identified by the 'From' field in the e-mail header, which contains the e-mail address or name of the sender.

  • Sender domain /sending domain - the domain that is used to send the email. This domain is identified with the sender's email address in the 'From:' field of the message. It is an important element in ensuring the security and authentication of an email message. It can be a subdomain, it is not always the same as the shop domain e.g. shop domain:, sender domain:

  • Shared IP - refers to an IP address used by several different senders to send e-mails.

  • Single opt-in - a type of process for obtaining consent from a user to subscribe to a service or receive marketing communications by means of a single and unambiguous confirmation. In the case of an email subscription, this means that the person wishing to join the subscriber list provides their email address, confirms, e.g. by clicking the sign-up button on a form, and is automatically added to the list without the need for additional verification or confirmation.

  • SMTP (Simple Mail Transfer Protocol) - the mail server responsible for sending emails from one email system to another. The SMTP protocol is used to transfer e-mails between different mail servers or between a mail client and a mail server.

  • Soft bounce - blocking of message delivery due to a temporary cause, e.g. a full inbox or temporary failure of the recipient's server.

  • Spam - unsolicited bulk correspondence, in the form of uninvited emails. Spam messages are usually sent to large numbers of recipients without their consent and usually contain advertisements, promotional content or links to websites.

  • Spam Assassin - an open-source spam filter system that is used to identify and flag emails as spam. It is a popular tool used by many organizations, email service providers, and system administrators to effectively reduce the number of unwanted messages in user’s inboxes.

  • Spam bounce - appears when an email message is returned to the sender as 'bounced' (incorrect) due to it being considered spam by the recipient's system. This means that the message was not delivered to the recipient's mailbox.

  • Spam trap - an email trap address, which is used to identify senders who send unsolicited or illegal emails and do not follow security standards or email sending ethics.

  • SPF (Sender Policy Framework) - an email authentication standard that helps verify that a specific mail server is authorized to send email on behalf of a domain. SPF adds a layer of security, helping to combat practices such as spoofing and phishing.

  • Spoofing - a technique in which a person or system impersonates another person, organization, device or server to achieve a specific goal. Spoofing can occur in a variety of contexts, but in the context of IT security and email communications, we most commonly talk about two types of spoofing: email spoofing (the sender forges an email address so that it appears that the message is coming from another person or organization) and IP spoofing (the attacker forges an IP address to hide the real address and confuse communication systems).


  • Transactional message - a type of message sent automatically in response to a specific user action or to a user transaction on a website or application. Transactional messages are intended to convey important information to the user regarding the action taken.

  • TXT (Text) - a type of DNS record that stores any text. It is mainly used to store information related to a particular domain. TXT records have a variety of uses, including confirming the identity of a domain, providing security information, service configuration or even storing general information.


  • Unsubscribe (from database) - a change in the status of a user from subscribed to unsubscribed, caused by the recipient's decision not to wish to receive marketing communications from a particular sender. It is a clear expression of a wish to be removed from a subscriber list, database or mailing list.

  • UTM (Unified Threat Management) - a system for tagging web links using special parameters to monitor the effectiveness of online marketing campaigns. UTM parameters are added to the URL, making it possible to track where visitors come from, what actions they take on the site and which campaigns or traffic sources generate conversions.


  • Whitelist - a list that includes email addresses, domains or IP numbers that are considered trusted and allowed. In the context of email marketing or email deliverability, the creation of a whitelist means that specific email addresses or domains are included in safe lists, increasing the chances of an email being delivered directly to the inbox rather than to the spam folder.

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