We're excited to announce React Email 4.0, featuring:

• Linter
• Spam Score
• Compatibility Checker
• Responsive Preview
• New Components

Update today and check the upgrade instructions below.

npm i react-email@latest

React Email now has 422,541 weekly downloads on npm, that is a 56% increase since the last major release 5 months ago.

We also have 15,509 stars on GitHub and would like to thank all the 154 contributors who made this possible.

Linter

The new Linter tool will analyze every link in your email to see if it's valid or not.

• If the links are valid and returning a 200 response status
• If the links are secure and using HTTPS instead of HTTP

It will also try to load every image in your email and recommend tips to improve it.

• If the images are optimized and no bigger than 1 MB
• If the images are accessible and contain alt text

Spam Score

The Spam Score will look at your email content and use a robust scoring framework to determine if the email is likely to be spam.

It's powered by SpamAssassin, the #1 open source anti-spam platform.

Here are some of the checks it performs:

• If the email has common spam words related to pharmaceuticals, scams, or lottery.
• If the email has an unusually high number of URLs in the email body.

Compatibility Checker

The new Compatibility Checker will see how well the HTML/CSS is supported across popular mail clients like Outlook, Apple Mail, and more.

It's powered by Can I Email, an open source repository of features and their compatibility for each email client.

There are hundreds of checks available, but here are some of the most common ones:

• If the HTML contains <svg> which is not supported by Gmail
• If the CSS contains display: flex which is not supported by Outlook

Responsive Preview

React Email now comes with a Responsive Preview, so you can see how your email will look like on different device sizes.

There are presets for mobile and desktop, and you can also customize the width/height of the preview.

New Components

We've added 8 new components that you can copy and paste into your emails.

They include Bento Grids, Pricing Tables, Feature Lists, Ratings, and more.

Upgrade instructions

Update your react-email package to 4.0.x.

You can also check if you have any missing dependencies for your emails to be bundled.

Conclusion

If you want to know all the details about this release, check the React Email Changelog.

If you have any problems upgrading, feel free to share on GitHub or X.