What's a 3D doing in this HTML?

html

email-encoding

best-practices

troubleshooting

byAnton Shumikhin·Aug 20, 2024

The "3D" you're seeing is quoted-printable encoding for the = character. This encoding is commonly used in HTML emails to handle non-ASCII characters.

Example:

<!-- Quote-unquote "3D" storage in HTML email—Encoded -->
style=3D"color: #333;"

<!-- How it looks to us, mere mortals—Decoded -->
style="color: #333;"

Replace =3D with = when dealing with HTML outside of an email context to avoid any side-effects.

Decoding the '3D' Mystery in HTML Emails

The occurrence of "3D" in HTML content, especially in emails, is actually a result of quoted-printable encoding. This encoding method is used for the safe transmission of non-ASCII characters and few special ASCII characters such as '='.

How '3D' Magic Works

These non-ASCII and special characters are converted into a standard ASCII representation. In this scenario, "3D" is the hex value for = in ASCII. This method ensures consistency of data across various email clients.

Choosing the Right Spell for Avoiding '3D'

This "3D" is not a design feature but an important part of maintaining content integrity during email transmission. How you handle these depends on your environment:

For Swift_Mime users, adjusting encoder settings by choosing something like RawContentEncoder can prevent an unintentional "=3D" conversion.
If you're on Laravel and dealing with Google Mail, tweaking some settings can help you dodge the "3D bullet."

The power to prevent "3D" trickeries lies in your hands and your toolset. So, wield them wisely!

The Dos and Don'ts for Dealing with Email Encoding

Just like any recipe, encoding email content also has a list of things to follow and avoid:

Encoding Best Practices

Specify the character set to prevent misconstrued interpretations.
Test across multiple email clients to ensure they are displayed as intended.
Utilize email design tools to minimize encoding issues and implement best practices.

Troubleshooting Tips

If you're spotting unwanted "3D" artifacts in Gmail, consider switching to a different email sending library.
Beware of template pre-processors that can alter encoding before sending.
Keep a tab on email service provider documentation for updates or changes.