{"id":84111,"date":"2025-02-27T16:49:27","date_gmt":"2025-02-27T16:49:27","guid":{"rendered":"https:\/\/mailrelay.com\/glosario\/sender\/"},"modified":"2026-09-26T07:28:42","modified_gmt":"2026-09-26T07:28:42","slug":"sender","status":"publish","type":"glossary","link":"https:\/\/mailrelay.com\/en\/glossary\/sender\/","title":{"rendered":"Sender"},"content":{"rendered":"\n

The sender is the person, company or organization that sends a message: a letter, a package or an email. Its opposite is the recipient<\/a>, the person who receives it.<\/p>\n\n\n\n

It sounds like a simple idea. But in email marketing it decides much more than it seems. It affects whether people open your email, whether they trust it and even whether it reaches the inbox<\/a>.<\/p>\n\n\n\n

What is a sender?<\/h2>\n\n\n\n

In plain terms, it’s someone who sends something to someone else. The word comes from the verb to send<\/em>, and common synonyms include dispatcher, shipper and, in communication theory, transmitter.<\/p>\n\n\n\n

So the concept always answers the same question: who is sending this? It doesn’t matter whether we’re talking about a postcard, a courier parcel or a newsletter.<\/p>\n\n\n\n

Who is the sender of a letter or a package?<\/h2>\n\n\n\n

In postal mail, it’s the person who ships the item, and their details appear in the return address. That includes their name, street address, city, postal code and, when needed, the country.<\/p>\n\n\n\n

In the United States and the United Kingdom, the return address usually goes in the top-left corner of the front of the envelope, although some people write it on the back. On parcels it appears on the shipping label, next to the recipient’s details. Its purpose is practical: if the item can’t be delivered, it goes back to that address.<\/p>\n\n\n\n

\"Where<\/figure>\n\n\n\n

The sender of an email<\/h2>\n\n\n\n

In an email, it’s the first thing you see in your inbox, in the “From” field. It has two parts: a display name (for example, “Laura from Mailrelay”) and the email address<\/a> the message comes from.<\/p>\n\n\n\n

Behind the scenes, though, an email carries several headers related to who sent it. They are defined by the Internet Message Format<\/a> standard, and it’s worth knowing them:<\/p>\n\n\n\n

Header<\/th>What it shows<\/th>Example<\/th><\/tr><\/thead>
From<\/td>The author of the message; what the recipient sees<\/td>Laura from Mailrelay<\/td><\/tr>
Sender<\/td>Who technically sends it, if different from the author<\/td>mailings@mailrelay.com<\/td><\/tr>
Reply-To<\/td>The address that receives replies<\/td>support@yourcompany.com<\/td><\/tr>
Return-Path<\/td>The address that receives bounces<\/td>bounces@yourcompany.com<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

The Return-Path<\/a> is usually hidden, although mailbox providers use it to check authentication. And Reply-To is handy when you want to send from one address and receive replies at another.<\/p>\n\n\n\n

\"The<\/figure>\n\n\n\n

Sender vs. recipient: what’s the difference?<\/h2>\n\n\n\n

The sender sends and the recipient receives, as simple as that.<\/p>\n\n\n\n

An email has only one author, but it can have many recipients: those in the “To” field and those in CC and BCC<\/a>. In an email marketing campaign, every subscriber on your list is a recipient, while your brand signs every send.<\/p>\n\n\n\n

Why the sender matters so much in email marketing<\/h2>\n\n\n\n

Before reading the subject line, many people check who is writing to them. If they recognize the name, they open. If they don’t, they ignore it or mark it as spam. That’s why the “From” name affects your open rate<\/a> as much as the email subject line<\/a> itself.<\/p>\n\n\n\n

On top of that, Gmail, Outlook and Yahoo judge every send based on sender reputation<\/a>. That reputation depends on complaints, bounces, volume and, above all, on whether the domain is properly authenticated.<\/p>\n\n\n\n

Since February 2024, Gmail and Yahoo require every company that sends email to authenticate it with SPF<\/a> or DKIM<\/a>. If you send more than 5,000 emails a day to their users, you also need DMARC<\/a>. Add to that a one-click unsubscribe link and a spam rate below 0.3%. Microsoft has applied similar rules to Outlook.com since May 2025. You’ll find the details in our guide to bulk sender requirements<\/a>.<\/p>\n\n\n\n

Authentication also protects your customers. Without it, anyone could impersonate your brand through spoofing<\/a> and launch phishing<\/a> campaigns in your name.<\/p>\n\n\n\n

Send from your own domain and reach the inbox<\/p>

Mailrelay guides you through authenticating your domain with SPF, DKIM and DMARC and confirming your senders in minutes.<\/p>Create a free account<\/a><\/div>\n\n\n\n

How to choose and set up a good sender<\/h2>\n\n\n\n

A good sender is recognizable at a glance and gets past mailbox provider filters. These are the keys:<\/p>\n\n\n\n