Can I email…

Can I email… is an open-source Jekyll website that publishes email client support tables for HTML and CSS features, built to answer the recurring question 'can I email this CSS property or HTML element?'. The project stores feature data in _features files and generates compatibility tables at caniemail.com, plus an embed-friendly version at embed.caniemail.com via a separate _config.embed.yml configuration. It is maintained on GitHub by user hteumeuleu, released under the MIT License, and sponsored by Resend, an email API service.

What is Can I email…?

Can I email… is an open-source Jekyll site that provides support tables for HTML and CSS features in email clients. The project takes feature definitions stored in _features data files and renders them as searchable compatibility tables on the public website. It runs on GitHub Pages with a homemade theme, uses Sass for CSS compilation, and includes a separate embed build configured through _config.embed.yml.

Key Features

• Email client support tables — Data-driven reference showing which HTML and CSS features work across major email clients.
• Jekyll + GitHub Pages — Static site generation with a homemade theme; runs as a GitHub Pages site, making it easy to host and version.
• Sass CSS compilation — Styles are written in Sass files under _sass and compiled into one CSS file in assets/css/.
• Embed build — A separate embed version of the site is produced with bundle exec jekyll serve --config _config.embed.yml.
• Test files — Includes HTML test files in the tests folder for verifying HTML and CSS feature support.
• News posts — The _posts folder contains latest news entries so the site can announce updates.
• MIT license — Free to reuse and modify for any purpose, with attribution.

Who is it for?

• Email developers — Use the support tables to check whether a specific CSS property works in the clients your subscribers use before you code a campaign.
• Email marketers — Plan campaign layouts that avoid unsupported CSS features, reducing rendering issues in Outlook, Gmail, and Apple Mail.
• Email tooling vendors — Reference the feature data and test files to inform your own email rendering and testing tools.

What can you do with Can I email…?

• Email developers: quickly look up support for flexbox, media queries, or other modern CSS features in email clients.
• Email designers: compare client differences in HTML element rendering by reading the generated tables.
• Contributors: clone the repository, add new feature data, write test files, and submit pull requests to improve coverage.

How does Can I email… work?

The site runs locally by cloning the repository, running bundle install to install Jekyll and dependencies, and starting a local server with bundle exec jekyll serve. For the embed version, use bundle exec jekyll serve --config _config.embed.yml. The static site is then deployable to GitHub Pages.

FAQ

Is Can I email… free?

Yes. The source code is published under the MIT License, so it is free to use, modify, and distribute for personal or commercial projects.

How do I run it locally?

Clone the GitHub repository, run bundle install, then bundle exec jekyll serve. Open http://localhost:4000 in your browser.

How do I add a new HTML or CSS feature?

Create a feature data file in the _features directory and optionally add a corresponding HTML test in the tests folder. The site rebuilds automatically when Jekyll serves locally.