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

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 wall of...
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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 Mailjet by Sinch, 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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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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Understanding the Gmail automated unsubscribe feature
Ah, email, the final communication frontier. From the early days of AOL to today’s large amount...
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Unsubscribe link: Why you need to include it in all your marketing emails
We’ve spoken many times about building a contact list as one of the main steps in your email marketing strategy...
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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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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...
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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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Sender score and email reputation: What are they and how to improve them
Everyone likes good scores, whether they be in sports, video games, or academics...
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Spam traps: What are they and how to avoid them
When it comes to online mail, spam traps can be the bane of many companies’ existence...
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What is phishing?
Even though technical security measures are improving constantly, phishing remains one of...
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