Deliverability Glossary
Everything you need to know about email deliverability
A
A record
This is a type of DNS record that links a domain name to an IP address. In simple terms, it allows browsers or email tools to know where the website or server associated with a domain is located. For example, it helps direct links in an email to the correct server. In the context of email marketing, A records are useful for displaying reliable links in messages, which improves deliverability. They are not configured in your email sending tool, but in the DNS settings of your web host.
B
Blacklist
A blocklist is a list used to identify email senders that are considered suspicious or unwanted. If your IP address or domain name is on this list, your emails may be blocked (bounces) or end up in spam. These lists are used by email services (such as Gmail or Microsoft) to protect their users. Being on a block list can harm your deliverability. It is therefore important to send high-quality emails to avoid being added to these lists.
BIMI
This technology allows you to display your official brand logo directly in the inbox, next to your emails. For this to work, you must prove that your domain is secure and that your emails are properly authenticated (via SPF, DKIM, and DMARC). You must also host and save the logo in a specific format (SVG) and declare it in your domain’s DNS settings. BIMI builds user trust, improves brand recognition, and can support your deliverability. In short: it’s an easy way to show that your emails are legitimate, reliable, and professional.
Blocking
Blocking occurs when an email is prevented from reaching the inbox by the email provider (such as Gmail, Outlook, etc.). This can happen for several reasons: a temporarily blocked IP address, content deemed suspicious, or an unusual volume of mailings. Unlike a bounce, the email is not returned, it is simply blocked at the point of entry. These blocks can affect your deliverability. It is therefore essential to identify the cause and adjust your practices to prevent them from happening again.
Bot (automated robot)
A bot is a computer program that automatically performs actions on the Internet. In the world of email marketing, some malicious bots mass-register for forms using fake email addresses. This attack, called list bombing, can harm your deliverability by filling your contact lists with invalid addresses. This increases hard bounces (invalid addresses) and can damage your domain reputation. To protect your campaigns, it is important to use anti-bot tools such as captchas.
Bounce (Hard Bounce / Soft Bounce)
In email marketing, a bounce means that an email could not be delivered to its recipient. It “bounces” back to the sender. There are two types of bounces:
A hard bounce is a permanent failure, often caused by an invalid or blocked email address.
A soft bounce is a temporary failure, for example if the mailbox is full or the server is unavailable.
Too many bounces damage your reputation as a sender and can impact your deliverability. Regularly cleaning your email list helps to limit these errors.
C
CAPTCHA
A CAPTCHA is a security test used to verify that a user is human, not a robot. It often takes the form of images to identify, distorted letters to copy, or checkboxes to tick. Its purpose is to prevent automated actions that could compromise the security of a website or registration form. In email marketing, it helps protect subscription forms from fraudulent registrations, which helps maintain the quality of mailing lists and improve deliverability.
CAN-SPAM (Controlling the Assault of Non-Solicited Pornography And Marketing Act)
The CAN-SPAM Act is a US regulation governing the sending of commercial emails. It requires companies to include a clear unsubscribe link, not to mislead recipients with false subjects or senders, and to respect the choice of users who no longer wish to receive emails. Enacted in 2003, it aims to limit spam and protect consumers. Complying with CAN-SPAM is essential for sending emails legally.
CAN-SPAM Act
The CAN-SPAM Act is a U.S. regulation governing the sending of commercial emails. It requires companies to comply with certain rules: clearly indicate the sender, do not use misleading titles, include a contact address, and above all, provide an unsubscribe link. Recipients must be able to easily remove themselves from mailing lists. Failure to comply with this law can result in heavy penalties. Following CAN-SPAM is essential for sending legitimate emails and maintaining good deliverability.
CASL (Canada’s Anti-Spam Legislation)
CASL is the Canadian law that regulates the sending of commercial emails. It requires companies to obtain clear consent before sending a message to an individual. Each email must also contain information about the sender and an unsubscribe link. The aim is to protect users from spam. Failure to comply can result in severe penalties. Compliance with CASL is essential for any company that sends emails to Canada.
Catch-all
A catch-all is an email address configured to receive all messages sent to non-existent addresses within the same domain. For example, if someone sends a message to a misspelled address such as test@votredomaine.com, the email will still be redirected to a defined mailbox, such as contact@votredomaine.com. Although convenient for ensuring nothing is missed, a catch-all can hinder deliverability because it prevents invalid addresses from being identified and can encourage the accumulation of spam. It is therefore not recommended for professional marketing mailings
CCPA (California Consumer Privacy Act)
The CCPA is a US law that protects the privacy of California residents. It gives consumers the right to know what personal data is being collected, to request its deletion, and to refuse to allow it to be sold. For companies that send emails, this means greater transparency and strict compliance with consent requirements. Even if you are not based in the United States, the CCPA applies if you target contacts in California. Complying with it builds trust… and your reputation as a sender.
Clipping (Gmail clipping) > Clipping occurs when an email is too long and Gmail hides part of it. This usually happens if the message exceeds 102 KB. In this case, the bottom of the email is cut off and replaced by a “Show entire message” link. This clipping can skew your open statistics, as the tracking pixel at the bottom of the email is not always loaded. To avoid this problem, it is advisable to lighten your emails: clean code, simplified content, and optimized layout.
CNAME (Canonical Name)
A CNAME record is a type of DNS record that allows one domain name to point to another. For example, www.votresite.com can be redirected to yourwebsite.com without having to duplicate the settings. CNAMEs are often used to customize tracking links in emails with your own domain name. This builds trust with recipients and improves deliverability. Changing a CNAME does not directly change the IP address, but follows that of the main linked domain.
Cold emailing > Cold emailing is an email prospecting technique that involves contacting a prospect who does not know you or has not interacted with your brand before. It is often used in B2B to initiate an initial exchange with a potential customer. The goal is to create a personalized contact and spark interest without being intrusive. For cold emailing to be effective and comply with deliverability rules, it must be well-targeted, relevant, and always compliant with data protection laws.
CRM (Customer Relationship Management)
A CRM, or customer relationship management tool, is software that centralizes all information related to your prospects and customers: contact details, communication history, orders, preferences, etc. It allows you to track every interaction, automate certain sales or marketing tasks, and improve collaboration between your teams. With a clear overview, a CRM helps you personalize communications, build customer loyalty, and optimize your campaigns, especially your email campaigns. It is a strategic ally for effectively managing your customer relationships and improving your marketing performance.
D
DDoS (Distributed Denial of Service) attack
A DDoS attack involves saturating a server or website with a very large number of requests from many different sources. The aim is to make it unavailable or very slow, preventing legitimate users from accessing it. A DDoS attack can block sending or receiving servers, disrupting email deliverability. As there are multiple sources, it is difficult to block the attack. This is why it is important to have good technical protections in place to guard against it.
Dedicated IP address
A dedicated IP address is an IP address used solely by your company to send emails. It is not shared with anyone else. This gives you complete control over your sender reputation and optimizes your deliverability. It is the ideal solution if you send a large volume of emails or have specific customization needs. To be effective, a dedicated IP must be properly warmed up before intensive use.
Deliverability
Deliverability refers to an email’s ability to reach the recipient’s inbox without being blocked by spam filters or redirected to junk mail. Good deliverability depends on several factors: the sender’s reputation, the quality of the contact list, the content of the email, and even domain authentication. If your emails don’t reach their destination, even if they are sent correctly, your campaign loses its effectiveness. Working on your deliverability is therefore essential for successful email marketing.
Deliverability rate
The deliverability rate is the percentage of emails sent that actually reached the recipients’ inbox (and not their spam or promotions folder). It is generally calculated as follows: Number of emails delivered ÷ Total number of emails sent × 100. A good deliverability rate indicates that your sending infrastructure, sender reputation, and contact database quality are solid. It is a key performance indicator (KPI) for any email marketing strategy.
Delivery rate
The delivery rate corresponds to the percentage of emails accepted by Internet service providers (ISPs). This means that the messages have not been blocked or rejected, but it does not necessarily guarantee that they will arrive in the inbox: they may also end up in spam. A good delivery rate shows that the technical infrastructure is in place, but it is not enough to assess true deliverability.
DKIM (DomainKeys Identified Mail)
DKIM is an email authentication technology that adds a digital signature to each message sent. This signature allows email services to verify that the email actually comes from the specified domain… and that it has not been modified during transmission. For DKIM to work, a specific entry (TXT record) is added to the domain’s DNS. This is an essential step in protecting your emails from hacking, building recipient trust, and improving your deliverability.
DMARC (Domain-based Message Authentication, Reporting, and Conformance)
DMARC is a security protocol that helps protect a domain name against identity theft. It works in conjunction with SPF and DKIM, two other email authentication systems. With DMARC, you can tell email services what to do if an email appears to be fraudulent: accept it, quarantine it, or reject it. This protocol also allows you to receive reports on unauthorized sending attempts. By enabling DMARC, you improve the deliverability of your campaigns and strengthen trust in your emails.
DNS (Domain Name System)
DNS is a system that links a domain name (such as yourwebsite.com) to its technical address on the Internet. It can be compared to a web phone book. DNS plays a key role in emailing: it allows you to configure important records such as SPF, DKIM, or DMARC, which are used to authenticate your emails. These settings are configured through a DNS provider, such as Cloudflare or GoDaddy. Properly configuring your DNS is essential for securing your emails and improving deliverability.
Domain
A domain is the unique name that identifies a website or email address on the Internet, such as yourcompany.com. In emailing, the domain is used to send messages, display links, or load images. It must be registered with a provider (such as OVH, GoDaddy, etc.) before it can be used. A well-configured domain allows you to authenticate your emails and improve your deliverability. It also represents your brand image to recipients.
Domain authentication
This method allows you to prove that your emails are actually sent by your company. Thanks to this verification, email services (such as Gmail or Outlook) can confirm that the sender address used really belongs to you. This helps protect your brand, limit the risk of phishing, and improve your deliverability. To enable this authentication, protocols such as SPF, DKIM, or DMARC are configured in your domain’s DNS settings.
Domain reputation
Domain reputation is a trust indicator used by email providers to assess the legitimacy and reliability of your domain name. It directly influences email deliverability: a domain with a good reputation will see its messages arrive in the inbox, while a suspicious domain will more often be filtered as spam. This reputation is built up over time based on your sending practices: list quality, complaint rate, sending frequency, open rate, etc. Maintaining your domain reputation is essential for effective email campaigns.
Double opt-in
Double confirmation, also known as double opt-in, is a two-step registration process. After filling out a form, the user receives an email asking them to confirm their address by clicking on a link. This validation proves that the email address is active and that the person really wants to subscribe. This helps build a clean and engaged contact list, which improves deliverability and reduces the risk of spam or bounces.
E
Email engagement
Email engagement refers to how recipients interact with your emails: opens, clicks, replies, or forwards. The more your contacts interact with your messages, the better your sender reputation becomes. Email providers (such as Gmail or Outlook) analyze this engagement to decide whether your emails deserve to arrive in the inbox… or in spam. Good engagement is therefore a key factor in deliverability. It depends mainly on the quality of your content and the targeting of your mailings.
Email header
The header of an email is the visible part at the top of the message, which indicates who sent it, who it is addressed to, and what the subject is. It includes the “From” field, the “To” field, and the subject line. These elements are often the first things the recipient sees before even opening the email. A clear, consistent, and reassuring header builds trust and increases the chances of the email being opened. It also plays an important role in deliverability, as some spam filters analyze this information.
Email marketing
Email marketing is a marketing strategy that involves sending bulk emails to a list of qualified contacts with the aim of promoting a product, service, or content. These emails are sent using email marketing software that automates campaigns and tracks key indicators such as open rates, click-through rates, and unsubscribe rates. When used effectively, email marketing remains one of the most profitable channels in digital marketing. However, to ensure that a message actually reaches the inbox, deliverability must be closely monitored.
Email warm-up
Email warm-up is the process of gradually sending an increasing volume of emails from a new IP address or domain. The goal is to build a good reputation as a sender with email providers (ISPs) and prevent your messages from being perceived as spam. Warm-up generally lasts several weeks and follows a specific schedule to get servers used to your activity. When done correctly, it improves deliverability and prepares your campaigns for the long term.
ESP (Email Service Provider)
An ESP is an online tool that allows companies to send emails to a list of contacts. It is used to create campaigns, send them automatically, track results (such as opens or clicks), and manage unsubscribes. An ESP also helps comply with anti-spam rules and improve email deliverability. It is a key element in sending marketing or transactional messages in an efficient, reliable, and professional manner.
G
GDPR (General Data Protection Regulation)
The GDPR is a European law that regulates the protection of personal data. It came into force in 2018 and applies to any company that collects or uses data from individuals located in the European Union, even if the company is based elsewhere. This means that you must obtain clear consent before sending messages and allow users to manage or delete their data. Complying with the GDPR is essential to protect privacy… and to avoid penalties.
Graymail
Graymail is a type of email that the recipient has agreed to receive but no longer reads. For example, a weekly newsletter or promotion that eventually loses its appeal. Even though it’s not spam, some users may report it as such, which can hurt your deliverability.
Too much graymail can lower your open rates and impact your domain reputation. To avoid this, it’s important to send useful messages that are tailored to each contact
H
Hard bounce
A hard bounce is a permanent failure to deliver an email. This usually occurs when the recipient’s email address is invalid, deleted, or misspelled. The email cannot be delivered and never will be, even if you try again. A high rate of hard bounces can damage your reputation as a sender and affect your deliverability. It is therefore essential to regularly clean up your contact list to remove addresses that generate this type of bounce.
Honeypots
A honeypot is an old, real email address that has been abandoned by its user and then reactivated by an email provider in order to detect senders who do not maintain their lists properly. If you continue to send emails to this inactive address, it shows that you are not regularly cleaning up your contact database. As a result, this can negatively impact your deliverability, damage your reputation as a sender, and cause provider filters to flag you as a spammer.
HTML (HyperText Markup Language)
HTML is the language used to structure the content of a web page or email. It allows you to add visual elements such as styled text, images, links, and buttons. In email marketing, HTML is used to create messages that are more attractive than plain text emails. It must be well coded to ensure proper display on all devices, as well as good deliverability, because code that is too heavy or poorly optimized can trigger spam filters
I
Inbox provider
An inbox provider (also known as an email provider) is a service that allows users to send, receive, and store emails. It provides an email address and email storage space that can be accessed via the web, an application, or software. Services such as Gmail, Outlook, and Yahoo are examples of this. These providers play a key role in deliverability: they use spam filters and strict rules to decide which emails arrive in the inbox… or in the junk folder.
IP address (Internet Protocol)
An IP address is a number that identifies a device on the Internet, much like a license plate. In emailing, this number indicates where emails originate. Services such as Gmail and Outlook use it to check whether the sender is trustworthy. If the IP address has a good reputation, messages are more likely to arrive in the inbox. If it is associated with domains/senders reported as spam, emails may be blocked or end up in the junk folder.
IP address reputation
IP address reputation refers to the trust that email providers (such as Gmail or Outlook) place in the IP address used to send your emails. This reputation directly influences deliverability: the better it is, the more likely your messages are to reach the inbox. Conversely, a poor reputation can result in your emails being classified as spam or even blocked altogether. Reputation is determined by several criteria, including complaint rate, bounce rate, sending frequency, and mailing list quality. Maintaining a good reputation is essential to the success of your email campaigns.
ISP (Internet Service Provider)
An ISP is a company that provides its customers with Internet access at home or at the office. In addition to the connection, some ISPs also offer an email service with an email address (for example: nom@fai.com). However, these mailboxes are often more limited than those offered by specialized email providers. ISPs also manage their own spam filters, which can affect the deliverability of your emails if you contact addresses hosted by them.
K
KPI
In email deliverability, a KPI (key performance indicator) allows you to track the quality of email sending and receiving. These indicators measure essential data such as delivery rate, inbox placement rate, number of hard bounces, and spam complaints. These KPIs help you assess the reputation of your domain or IP, identify technical issues, and adjust your sending practices to maximize inbox delivery. Regularly analyzing these indicators is crucial to maintaining good deliverability.
L
List cleaning
Email list cleaning involves regularly cleaning your contact database to keep only valid and active addresses. This means removing emails that no longer work (hard bounces), those that never respond to campaigns, or people who have unsubscribed. This improves deliverability because it reduces unnecessary mailings and limits the risk of spam. A clean list allows you to send emails to recipients who are genuinely interested, which enhances the sender’s reputation.
List-Unsubscribe
List-Unsubscribe is a technical header added to an email that allows providers such as Gmail or Outlook to display a visible unsubscribe button directly in the email interface. This link can point to an email address or a dedicated URL, or even combine the two. It makes it easier to manage unsubscriptions, improves the user experience, and contributes to better deliverability. By simplifying the process of leaving the list, you reduce the risk of spam complaints. Most ESPs (Email Service Providers) add it automatically, but it is essential to check that it has been set up correctly.
M
Mail Builder
A mail builder is a tool or software that allows you to create personalized emails without the need for coding. Thanks to an intuitive interface, often drag-and-drop, it allows you to easily design the layout, add images, text, buttons, or even dynamic blocks. Using an email builder guarantees a professional result that is consistent with your visual identity and optimized for reading on all devices (mobile, tablet, computer). An email that is well constructed with an email builder also complies with best technical practices, which improves the deliverability of your campaigns.
Mailing list
A mailing list is a collection of email addresses belonging to contacts who have agreed to receive your communications. It can be segmented according to various criteria, such as subscription to a service, interest in an offer, or membership of a target group. Effective management of your mailing list is essential for improving email deliverability, avoiding spam complaints, and optimizing open and click-through rates. In email marketing, a clean, engaged, and well-structured list is a key lever for establishing a relationship of trust with your recipients.
MBP (Mailbox Provider)
MBP stands for Mailbox Provider. This term refers to services that allow users to receive, send, and store their emails. Gmail, Outlook, and other online email services are examples of this. MBPs play a key role in email deliverability, as they apply spam filters and decide whether a message ends up in the inbox, in spam, or nowhere at all. Understanding how they work will help you optimize your campaigns.
MMT (Message Transfer Agent)
An MMT, or Message Transfer Agent, is software responsible for routing emails from one server to another. Its role is to transmit each email message from the sender to the recipient’s server, in accordance with messaging protocols (such as SMTP). The MTA acts as an essential technical intermediary in the email chain. It directly influences email deliverability, as a well-executed transfer ensures that the message arrives at the right place, without being blocked or encountering technical errors.
Multipart
A multipart email contains two versions of the same message: one in HTML (with formatting, images, links) and one in plain text. This format allows email services to automatically display the version best suited to the recipient’s device. In the absence of a text version, some providers (such as Microsoft or Gmail) may penalize deliverability or classify the email as spam. Multipart is therefore essential to avoid spam and ensure optimal readability on all devices, including connected objects such as smartwatches.
N
Newsletter
A newsletter is an email sent regularly to a list of contacts who have agreed to receive it. It contains useful or interesting information, such as news, promotions, advice, or updates related to a company, product, or service. In email marketing, newsletters are a key tool for maintaining relationships with subscribers, driving traffic to a website, and strengthening customer loyalty. To be effective, it must be relevant, well-structured, and comply with best practices for email deliverability.
O
Open rate
The open rate measures how many people opened your email after receiving it. It depends mainly on the subject line and the sender’s name. A good open rate indicates that your messages are attracting attention and sparking curiosity. It is a key performance indicator (KPI) for tracking subscriber engagement and optimizing your email marketing strategy.
Opt-in
Opt-in refers to the explicit consent given by a person to receive emails from a company. It is a key step in email marketing and an essential prerequisite for complying with the GDPR (General Data Protection Regulation). This voluntary agreement ensures that your contacts actually want to receive your messages, which improves deliverability and reduces spam complaints. Opt-in can be obtained via a registration form, a checkbox, or a double opt-in, thereby enhancing the quality of your database.
Opt-out
Opt-out refers to the action by which a person chooses to no longer receive emails from a sender. This is usually done by clicking on an unsubscribe link at the bottom of the message. To comply with laws such as CAN-SPAM, this request must be processed quickly, often within 10 days. Providing a clear and easy-to-use opt-out option is essential for respecting user privacy, avoiding spam complaints, and maintaining good deliverability.
P
Permission pass
A permission pass is a one-time email sent to inactive contacts asking if they still want to receive your messages. It is intended for people who signed up in the past but are no longer showing engagement. The goal is to confirm their consent: if the recipient clicks to remain subscribed, they remain on your list; otherwise, they are removed. This practice helps keep your list clean, maintain your deliverability, and comply with email marketing best practices.
Phishing
Phishing is a form of email fraud that aims to trick users into revealing sensitive personal information, such as passwords, bank details, or login credentials. The email often imitates a trusted company (bank, well-known platform, customer service, etc.) and redirects to a fake website designed to trap the victim. Phishing harms user security, but also the reputation of the domains being impersonated, which can impact the deliverability of legitimate emails.
R
Ramping (power-up)
Ramping, or power-up, is a key step in email warming. It involves gradually increasing the volume of emails sent from a new IP address or a new infrastructure, whether dedicated or shared. This process helps build a good sender reputation with email providers. A well-managed ramp-up limits the risk of blocking or being classified as spam, and promotes sustainable deliverability. Sending too many emails too quickly can, on the contrary, damage your reputation.
Responsive
Responsive design is a web design technique that allows a website to automatically adapt to all types of screens: computers, tablets, or smartphones. The content, images, and layout are reorganized according to the screen size to ensure smooth reading and comfortable navigation. In email marketing, responsive design is essential to ensure that your campaigns are readable and engaging, regardless of the device used by the recipient. It is an indispensable practice for improving user experience and conversion rates.
Routing
Email routing refers to the technical process by which an email is sent from a sending server to the recipient’s inbox. It encompasses all stages of an email message’s journey, including passing through servers, security checks (SPF, DKIM, DMARC), and spam filtering. Good routing ensures that emails are delivered quickly and to the right place, ideally in the main tab or inbox. It therefore plays a key role in email deliverability, especially for high-volume marketing and transactional campaigns.
S
Seed List
A seed list is a list of email addresses voluntarily added to your mailings to test the deliverability of your marketing campaigns. These addresses, often internal or neutral, allow you to check where your emails actually end up: main inbox, promotions tab, or spam folder. Seed list management involves analyzing the results of these tests to correct potential deliverability issues before sending out a mass mailing. It is an essential tool for ensuring that your messages reach their target audience and for refining your email marketing practices.
Segmentation
Segmentation involves dividing your contact list into subgroups based on specific criteria: interests, purchasing behavior, location, age, engagement, etc. This allows you to send campaigns that are more targeted, more relevant, and better suited to each profile. Good segmentation improves open and click-through rates, reduces unsubscribes, and enhances deliverability. In email marketing, it’s best to talk to the right person… at the right time, with the right message.
Sender Score
The Sender Score is an indicator that assesses the sending reputation of your IP address. It is calculated on a scale of 1 to 100 and reflects the trust that email providers (such as Gmail, Outlook, etc.) place in your emails. The higher your score, the more likely your messages are to reach the inbox rather than the spam folder. This score is influenced by several factors: complaint rate, bounce rate, sending volume, and presence on blacklists. Maintaining a good Sender Score is essential for optimal deliverability.
Sending address (email)
The sending address is the email address that sends the message. It is the address that the recipient sees in the “From” field when they receive an email. For example: contact@votreentreprise.com. It helps to know where the email is coming from and to recognize the sender. If this address seems strange or changes too often, spam filters may block your messages. To ensure your messages arrive in the inbox, it is important to use a clear, reliable sending address linked to your professional domain name and/or your brand/website.
Server
A server is a computer configured to provide resources or services to other devices called clients, often via a network such as the Internet. In the context of emailing, the server hosts and transmits emails, manages secure connections, and applies the protocols (SMTP, IMAP, POP) necessary to route messages to their recipients. It is essential to the proper functioning of electronic communication and email deliverability. A reliable and well-configured server reduces the risk of transmission errors or blocking by spam filters.
Shared IP address
A shared IP address is an address shared by several email senders. This means that your email campaigns are sent from the same IP address as other companies. The advantage? You benefit from the collective reputation if others send emails responsibly. But if another user engages in bad practices, it can affect your deliverability. This type of IP is often used by ESPs (email service providers) for small businesses or moderate volumes of emails.
SMTP
SMTP, which stands for Simple Mail Transfer Protocol, is the standard protocol used to send emails over the Internet. It acts as a digital postman, handling the transmission of your messages from your email software to the recipients’ mail servers. SMTP is essential to the proper functioning of the sending chain, particularly for email marketing campaigns or transactional emails. Correct SMTP configuration directly contributes to better deliverability, as it allows emails to be sent in an authenticated and secure manner, thereby reducing the risk of spam.
Soft bounce
A soft bounce refers to a temporary failure in the delivery of an email. This can occur if the recipient’s inbox is full, if their server is temporarily unavailable, or if the message is too large. Unlike a hard bounce, the email address is not necessarily invalid, but the message could not be delivered at that time. If soft bounces occur repeatedly, they can affect your deliverability rate. It is therefore important to monitor these addresses and clean them up if necessary.
SPF (Sender Policy Framework)
SPF is an email authentication protocol that verifies that the server used to send an email is authorized by the sender’s domain. In practical terms, it is a record added to your domain’s DNS that lists the IP addresses authorized to send emails on your behalf. This helps prevent identity theft (spoofing) and strengthens the trust of email providers. A well-configured SPF is essential for improving deliverability and protecting your sender reputation.
Spam filters
Spam filters are automatic systems used by email services to block suspicious or unwanted emails. They analyze each message according to several criteria: sender, subject, content, links, attachments, etc. If the email is deemed risky (spam, phishing, virus, etc.), it is placed in the junk mail folder or blocked before reaching the inbox. These filters protect users from online threats, but can also mistakenly block legitimate messages. Understanding how they work helps improve deliverability.
Spam word
A spam word is a word or phrase often associated with unwanted emails and detected as such by spam filters. These keywords, such as “free,” “100% guaranteed,” or “urgent,” can trigger alerts and penalize the deliverability of your emails. The more spam words a message contains, the more likely it is to end up in the spam folder, even if it is legitimate. To preserve your domain’s reputation and improve your open rates, it is essential to write your emails in a natural, clear manner without overly promotional language.
Spamtrap
A spamtrap is a trap email address used by email providers to identify negligent or malicious senders. It does not correspond to any real user and has never requested to receive emails. If you send a message to a spamtrap, it means that you are using a poorly maintained list or one that has been collected without consent. As a result, your domain or IP address may be penalized or even blacklisted, which seriously affects your deliverability. Properly cleaning your database helps avoid this risk.
Subdomain
A subdomain is an extension of a main domain, placed before it. For example, in email.yoursite.com, email is the subdomain. In email marketing, subdomains are often used to distinguish marketing or transactional emails from the main domain. This allows you to separate sending reputations, better organize your email infrastructure, and limit the impact in the event of a deliverability issue. Properly managing your subdomains helps maintain a good sender reputation.
T
The TINS (This Is Not Spam) action
TINS is an action taken by the recipient of an email when they click on “This message is not spam.” This tells their email provider (such as Gmail or Outlook) that your emails are legitimate and that they want to receive them. This action helps improve your domain reputation and increases your chances of landing in the inbox in the future. TINS is a strong positive signal for deliverability, as it shows that your messages are expected and appreciated.
Tracking Pixel
A tracking pixel is a small invisible image (usually 1×1 pixel) embedded in an email or web page. When a recipient opens the email, the pixel loads, allowing the message to be tracked and data such as the time, approximate location, or type of device used to be collected. It is a key tool for measuring the performance of an email campaign, particularly the open rate. Unlike cookies, it does not require user interaction, but its use must comply with applicable privacy rules.
Transactional email
A transactional email is an automatic message sent to a recipient following a specific action they have taken. Examples include order confirmations, acknowledgments of receipt, password reset links, and shipping notifications. These emails are not intended for promotional purposes, but to provide personalized information to the user. Crucial to the customer experience, transactional emails must arrive quickly and avoid the spam folder, hence the importance of managing their deliverability effectively.
TXT record
A TXT record is a type of entry in a domain’s DNS that allows free text to be stored. In emailing, it is mainly used to configure authentication protocols such as SPF, DKIM, or DMARC. These records help email providers verify that emails sent are authorized by the domain. Properly configuring your TXT records is essential to protect your identity, combat spam, and improve the deliverability of your campaigns.
U
Unsubscribe
Unsubscribing refers to the action of a user who chooses to no longer receive your emails. By clicking on the unsubscribe link in your message, they voluntarily remove themselves from your mailing list. This signal must be taken into account, as a high unsubscribe rate may indicate a lack of relevance in your campaigns. It is better to have an unsubscription than a spam complaint: it is a useful indicator for adjusting your content and improving your deliverability.
URL (Uniform Resource Locator)
A URL is the complete address of a web page or online resource. It allows a browser or email recipient to access a website, image, unsubscribe link, etc. A URL consists of a protocol (such as https://) and a domain name (such as www.mailsoar.com). In the context of email marketing, visible and reliable URLs are essential for gaining the trust of recipients and avoiding spam filters, especially when it comes to clickable links.
W
Web host
A web host is a service provider that provides server space to store website files, including tools related to sending emails. Thanks to the web host, your website and email campaigns are accessible online 24 hours a day. In addition to storage, the web host often provides data security, technical maintenance, and sometimes even DNS management, which is essential for email authentication. A reliable web host indirectly contributes to better deliverability by ensuring the stability and reputation of your domain.
Webmail
Webmail is an email service that can be accessed directly from a web browser. It allows you to send, receive, and view emails without installing any software, simply by logging into an online interface. Gmail, Outlook.com, and Yahoo Mail are examples of webmail services. Unlike locally installed email clients, webmail runs on a remote server. It is a widely used tool for managing emails from any connected device, making it an important channel to consider when optimizing the deliverability of email campaigns.
Whitelist
A list of email addresses, domains, or IP addresses that are considered trustworthy. When a domain is on this list, its emails are allowed to pass through spam filters more easily and arrive in the inbox. This is the opposite of a blacklist. In terms of deliverability, being on a security filter’s allowlist can significantly improve your delivery rates. This system allows you to trust certain senders… and block everything else by default.