CSS inlining involves taking CSS styles and incorporating them directly into the HTML markup of an email, placing styles within the style attribute of individual HTML tags.
Why should I?
CSS inlining is crucial for transactional emails due to the wide variety of email clients used by your users, each with its own way of interpreting and rendering CSS. Email clients vary greatly in their support for CSS, leading to inconsistencies in how emails are displayed if CSS is not inlined.
Without CSS inlining, emails that appear as intended in one client may look entirely different in another, potentially compromising the design and clarity of the communication. Inlining your CSS ensures that emails maintain their intended layout and style across all email clients, providing a consistent and reliable user experience.
What if I don't?
Not implementing CSS inlining in transactional emails can lead to significant issues in how these emails are rendered across different email clients. The styling defined in the head of an HTML document or in external stylesheets might not be applied consistently, or at all, in some email clients. This inconsistency can result in emails that look unprofessional, are difficult to read, or fail to convey the intended message effectively.
The lack of CSS inlining can negatively impact the user experience, potentially harming the reputation of the sender and reducing the effectiveness of communication. Ensuring CSS is inlined is therefore crucial for maintaining the integrity and consistency of transactional emails.
Tools of the trade
- Mailchimp's CSS Inliner : A tool provided by Mailchimp that allows you to quickly try CSS inlining in your browser.
- Premailer : A Ruby gem that converts CSS styles to inline styles, ensuring emails are displayed consistently across various email clients.
- Juice : A node.js library that provides CSS inlining capabilities. It can be used in server-side applications to automatically apply styles inline to HTML documents.
- css_inline : The new kid on the block. A library that supports many languages and platforms. It can also be used client-side.
These tools and libraries are essential for developers and marketers who aim to ensure their transactional emails are rendered correctly across all email platforms. They automate the process of CSS inlining, saving time and reducing the likelihood of rendering issues.
OK, so how can I inline my CSS?
Good news is it's not rocket science. Here are the steps you need to take:
- Select the CSS library that best fits your project's needs.
- Before sending an email to your email provider's API or SMTP server, use the library to convert your CSS to inline styles.
- Test the output across multiple email clients to ensure that the inlined CSS renders as intended. Tools like Email on Acid can provide comprehensive testing across a wide range of clients.
- Monitor the emails you send and review them periodically to ensure that they look as intended. A tool like Midflight can help you generate an inventory of your transactional emails automatically.
Implementing CSS inlining is a key step in ensuring that transactional emails provide a consistent and professional user experience, regardless of the email client used to view the message.