Mailjet blog
Deliverability
Everything you need to start building connections that matter.

What is the Gmail automated unsubscribe feature?
Ah, email, the final communication frontier. From the early days of AOL to today’s large-scale email-related services, clients, and more, it has undoubtedly changed our lives and evolved over the years. One of those email actors leading the way when it comes to...
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What do marketers need to know about email deliverability?
What does the term “email deliverability” mean to you? The truth is...there’s a lot more to it than simply getting messages delivered. If you think of email deliverability as the best practices you follow to avoid the spam folder and blocklists, you’re getting closer. But...
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How to avoid email spam filters
So, you're sick and tired of hearing about your beautiful emails landing in spam? We're glad you checked in. If you’re responsible for your organization’s email campaigns, you’re probably constantly thinking about how to avoid spam filters, spam words, and always...
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Unsubscribe link: Why it’s critical for your email marketing campaigns
We’ve spoken many times about building a contact list as one of the main steps in your email marketing strategy. We have also often repeated how important it is for you to have a clean list. In fact, you’re probably a bit tired of hearing all about it by now. We get it. But...
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Gmail Promotions tab: A guide to optimize email delivery
The Gmail Promotions tab’s hot debut in 2013 caused mixed reactions. Some marketing pundits predicted that it marked the end of email marketing as we know it. Others were less dramatic and just stated that it would have a negative impact on the opens and clicks of...
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Email file sizes: How big is too big?
Bigger isn’t always better for email marketers – especially when it comes to email file sizes. Trying to stuff large images or send big HTML files can hurt your email engagement and deliverability. So how big is too big for email file sizes? Is it time you put your email...
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Single vs. double opt-in: Which one should you use?
If you’ve been using single opt-ins for a while, the idea of double opt-ins may seem a little daunting. You’re effectively doubling the number of steps a user takes before their added to your lists. And this can be a little scary for most email marketers whose KPIs are...
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Email headers: What they are & how to read them
Hands up if you’ve heard someone talk about email headers, but have no idea what they are. Or even worse, maybe your technical team asked you to send them the full header of your email, and you’re frantically looking for it everywhere. In this post, we’re going to tell...
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DKIM setup: How to create, configure, and set up DKIM in 3 easy steps
You didn’t become an email marketer because you wanted to dive into complicated code all day. Ugh. And when you hear all these weird sounding acronyms like DKIM, SPF, and DMARC, your first instinct is probably to run for the hills. But then, when you encounter...
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Buying email lists doesn’t guarantee improved results
When your business is just starting out, you want to feel as if you’re doing all you can to grow your customer base. Stories like Harry's gathering 100,000 email signups in one week are inspiring, but they can pressure you to frantically check how to grow a contact list...
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Noreply email address: Best practices for your email strategy
Have you ever tried to contact a brand to get them to stop sending you emails, only to get back an automated reply that says your email failed to be delivered? If you have, you’ve met the villain of our story: the noreply email address. Noreply addresses are the brick...
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Email spoofing: How brand impersonation really works
Celebrity impressions are hilarious. Who doesn’t love a good Sean Connery or Marlon Brando impersonation? But when bad actors impersonate your brand through email spoofing, it’s no laughing matter. Because email is such a personal and trusted...
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Email list cleaning: Complete your chores before playtime
If we take a trip down memory lane (some of our lanes might be longer than others), we might remember our parents telling us if we didn't tidy our bedroom or help clean the dishes, we couldn't play with friends or go to a movie. Let's face it, none of us wanted to...
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Deliverability tips to avoid the spam folder this holiday season
The holiday season is almost upon us, which means marketers – especially those in retail – will soon start to increase their sending frequencies and will also widen their nets to reach out to as many contacts as possible. At Sinch Mailjet, we expect to see very high...
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What is the return-path and why do you need to customize it?
Have you ever heard of a return-path? If you haven’t, maybe you are missing one thing that you...
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8 ways to avoid ISP Blocklist
The Internet Service Provider (ISP) blocklist is probably your worst nightmare. Ending up on the blocklist is like having your domain name and IP address kicked out of the club, dropped from the mail server, and locked behind a firewall. (Plus, they threw away the...
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How to handle SPF and the 4 steps to create an SPF record
Do you find dealing with email spammers feels like playing a game of Whac-A-Mole? When you whack one, two more pop up in its place. With spammers, when you find a way of...
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Email throttling: An optimization guide
Have you ever started an email campaign, only to receive error codes time and time again? The doomed “message not sent because of server error”? It may not seem harmful, but...
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What is IP reputation and are there ways to improve it?
You know the old expression, “you’re only as good as your word”? In today’s complex marketing climate, Internet Service Providers (ISPs) judge your trustworthiness as harshly...
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IP address explained & basics you should know
The internet is an essential part of modern digital life. Humans use it for almost everything, from shopping to dating to appointments. Every time you use the internet, you use an IP...
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All you need to know about transactional email
Whether you're a small business, a non-profit, or a fast-growing startup, transactional emails play a critical role in shaping your customers' experience and perception. All you...
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Sunset policies in your email program
Email deliverability rules have changed. It’s not a numbers game anymore where more email addresses equal more potential customers. In fact, new laws actually penalize you for sending too many emails that go unopened. Enter the need for an email sunset policy...
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Improving your sender reputation to boost email deliverability
Deliverability. That's what’s at the center of any successful email marketer's focus...
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What’s cool about COIL
In terms of opt-in options, you probably think you’ve got them down. But we’re here to...
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