The pros and cons of MJML (Updated for 2026)

While email marketing still remains one of the most effective ways to reach customers, designing HTML emails that look great on all devices and browsers can be a daunting task. Fortunately, in the last few years, MJML has swooped in and changed the game. MJML is a markup language that makes it easy to design beautiful, responsive emails. It’s simple to learn, easy to use, and it’s quickly becoming one of the top go-to tools for email marketing. But if you’re still weighing the usefulness of MJML, here are some pros and cons to help you decide if it’s the right markup language for you.

Pros of using MJML

1. It’s easy to get started with MJML

The idea of learning a new markup language may seem somewhat intimidating or at least time-consuming, especially for those who have never tried coding, but MJML is designed for rapid adoption . In fact, it’s so easy that developers can likely pick it up in under an hour as a total beginner or in even less time if you’re already familiar with HTML. This is because MJML uses very simple syntax and the documentation isn’t overly technical, making it straightforward for those who just want to start coding their first email right away. For example, if you want to create a button in MJML, you would use the <mj-button> tag and defining its style via attributes.  You can even generate social media icons when you use the <mj-social> and <mj-social-element> tags. If you’re interested in a step-by-step tutorial on building a complete email in MJML, check out one of our previous blog posts.

2. Significant time savings

MJML being easy to use goes hand in hand with the language being a huge time saver. Coding emails with HTML can unfortunately involve a lot of complications, and using HTML alone to code emails will require extra work for styling and responsiveness. Since external CSS and JavaScript don’t work in most clients, you may find yourself writing a lot of HTML code just to create something simple—if you’ve ever tried to code an email with just HTML, you already know how crazy nesting tables can get. Naturally, the more code you have, the more likely things are to get a little messy, which leaves the door open for silly mistakes to be made. MJML abstracts this complexity into a streamlined syntax. By handling the heavy lifting of responsive breakpoints and client-specific fallbacks automatically, MJML allows developers to focus on content and design rather than troubleshooting rendering quirks for legacy inboxes. 

3. Excellent documentation

Nothing is worse than trying to learn a new markup language without the proper tools or guide. Fortunately, Mailjet, the creator of MJML, went to great lengths to ensure the most important aspects of coding are covered, such as component attributes, rendering behavior, and responsive breakpoints. On the official MJML website, you can find a detailed guide on how to create basic email elements, like sections, buttons, and images, as well as community components. You can also leverage community-contributed components to add advanced functionality to your emails. These contributions offer pre-built solutions for elements like QR codes and data charts, saving you the time of building them from scratch.  We also explain many of the MJML components in-depth in our MJML cheatsheet.

4. MJML is open source

This means that MJML has been specifically designed to be accessed, modified, and distributed by anyone for any purpose. This collaborative model allows people from all over to use their expertise and creativity to consistently improve MJML, helping both new and experienced users benefit. MJML has a standard collection of components, but as mentioned previously, users can create their own components and share them with the wider community. You’ll find step-by-step instructions here on how to make your own custom components when you’re ready.

5. There are multiple ways to use MJML

When it comes to coding with MJML, you aren’t locked into a single platform. Whether you’re a fan of visual editors or a terminal power user, there is a workflow that fits your style.

Here are the most effective ways to use MJML today:

• The online editor (MJML live): Perfect for quick prototypes or beginners. You can code directly in your browser with a side-by-side preview (no installation required).

• The VS Code extension: This is the "pro-choice" for most developers. It offers a lightning-fast live preview, syntax highlighting, and the ability to send test emails via Nodemailer or Mailjet without leaving your editor.

• Node.js & NPM: If you’re comfortable with the command line, installing MJML via npm allows you to bake email compilation directly into your development workflow or CI/CD pipeline.

• The desktop app: If you prefer a dedicated workspace away from your browser or IDE, the desktop app provides a clean, focused environment with a built-in preview.

• Gulp & modern bundlers: For complex projects, MJML integrates seamlessly with Gulp, Webpack, or Vite. This is ideal if you're using custom components or need to automate the rendering of hundreds of templates at once.

Check out the MJML community page for more useful tools, libraries, and plugins.

6. Automatic Outlook fallbacks (VML)

While the "New Outlook" transition is well underway, legacy versions of Outlook (2007-2019) still rely on the Microsoft Word rendering engine. Coding buttons with rounded corners or background images for these versions normally requires VML (Vector Markup Language).

MJML writes the VML for you. When you use <mj-button>, it automatically generates the hidden "ghost code" needed to make that button work in legacy Outlook.

7. Standardized breakpoints

In standard HTML, you have to manually define when an email "stacks" (moves from two columns to one) using media queries. This can lead to inconsistency across different campaigns.

MJML uses a standardized mobile breakpoint (usually 480px). This ensures that every email your team sends behaves exactly the same way on mobile, creating a consistent brand experience without manual testing for every single layout.

8. Minification and deliverability

Large HTML files are not just a design problem; they are a deliverability problem. Some spam filters flag excessively large files, and Gmail famously clips emails over 102KB.

The MJML engine includes a "minify" option. This strips out unnecessary whitespace and comments from the final HTML, helping you stay under the clipping limit and improving your chances of hitting the primary inbox.

9. Ease of collaboration

Because MJML code is much shorter than the compiled HTML it produces (often 1/5th the size), it is significantly easier to review in version control systems like GitHub or GitLab.

A team member can look at a "pull request" of MJML code and actually understand the changes. Reviewing a 2,000-line HTML file full of nested tables is nearly impossible, but reviewing 100 lines of MJML is simple.

10. Seamless API integration

For companies sending dynamic or transactional emails (like receipts or password resets), MJML offers an API.

Instead of storing messy HTML templates in your database, you can store clean MJML. Your system can send that MJML to the API and receive fresh, inbox-ready HTML in real-time. This makes it much easier to update your brand’s look across all automated emails at once.

Cons of using MJML

1. File weight constraints 

MJML generates a lot of code to ensure compatibility. In 2026, with richer media and more interactive elements, it is very easy to exceed Gmail’s 102KB clipping limit. If your design is overly complex, the compiled HTML might be "too safe," causing your email to get cut off in the inbox.

2. Not "Full" HTML

MJML is not a 1:1 replacement for HTML. It is a proprietary language. While it's easy to learn, your developers still have to learn the specific nuances of MJML tags. If you want to do something highly custom—like complex CSS animations or advanced interactive "hover-to-reveal" states—you often have to use <mj-raw>, which can defeat the purpose of using the framework.

3. Rigid layouts

MJML is built on a gutter-and-column grid system. If your designer provides a "broken grid" or an organic, overlapping layout, MJML can be frustratingly rigid. Modern utility-first frameworks (like Maizzle) offer more freedom for these "web-style" designs.

4. Learning requirements

Although it is easy to learn, MJML is still a proprietary abstraction.

Skills learned in MJML aren't 100% transferable to general web development. A developer might become an expert in MJML but still struggle to understand why an email is breaking in a specific client because the underlying HTML is hidden from them.

The verdict

In 2026, MJML remains the "Old Reliable" of the email world.

It is perfect for:

• Teams that need to ship high volumes of emails quickly.

• B2B companies that still see high traffic from legacy Outlook clients.

• Developers who want a "set it and forget it" responsive solution.

However, if you are building highly bespoke, lightweight, or "app-like" interactive emails, you might find MJML’s training wheels a bit too restrictive.

Summary of benefits