Overview

Fonts are an essential part of your brand identity. They help your emails look and feel consistent with your website, app, and other brand materials. However, unlike on your website, not every email app shows your custom fonts.

Custom fonts are brand-specific typefaces that are not pre-installed on devices. You use them to bring consistency between your emails and other brand materials, such as your website or app. For example, Gotham, Lato, Open Sans, and Proxima Nova, or any other typeface outlined in your brand guidelines.

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Note

When you include a custom font in an email, the email app must download it when the message is opened. If the app does not support custom fonts, it falls back to a default or safe font.

Safe Fonts: The Built-In Defaults

Safe fonts are the typefaces that already exist on almost every computer and phone. Because they are built in, every inbox can display them without downloading anything. You can use safe fonts to appear consistently across different devices and email clients.

These fonts are universally recognized across Windows, Mac OS, iOS, and Android, ensuring your emails remain readable.

Fallback Font Stacks

When you define fonts in email, you do not set just one font, instead put a stack of options. This way, if one font is not available, the inbox automatically tries the next one in line.

font-family: "Arial", "Helvetica", sans-serif;

The working order is as below:

• Inbox will first try Arial.
• If Arial isn’t available, it tries Helvetica.
• If neither is available, it falls back to the generic sans-serif family (e.g., Roboto on Android, Segoe UI on Windows, or San Francisco on Apple)

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Note

The last keyword (sans-serif, serif, or monospace) is not a specific font, it’s a safety net. This ensures your email always renders in a similar style, even if the exact fonts aren’t supported.

Default Case

Custom Font Support Across Email Clients

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Important Edge Cases

• Gmail may ignore fallbacks and use its own fonts (Roboto/Google Sans).
• Outlook for Windows often overrides everything and falls back to Times New Roman or Calibri.
• Samsung Email supports custom fonts only when the account is not Microsoft-based (e.g., Outlook/Hotmail/Live).

Best Practices for Using Custom Fonts in Email

To make the most of custom fonts in email campaigns, you need to balance brand consistency with readability across different inboxes. Always design with safe fonts in mind, since custom fonts act as a bonus rather than a guarantee. Your emails should still look professional even if they display in Arial or Times New Roman.

1. Ensure to set a proper fallback stack to ensure consistency. For example:

font-family: "FancyBrand", "Helvetica", "Arial", sans-serif;

If FancyBrand doesn’t load, the email will display Helvetica. If Helvetica isn’t available, it switches to Arial, and finally defaults to the closest sans-serif font.

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Note

Keep your design clean with just one or two fonts for faster loading and consistent style, and confidently test your emails with tools like Litmus or Email on Acid to see how they appear across 90+ devices and apps.

2. Use custom fonts strategically; they work best for headlines, hero sections, or special brand elements. For body text and critical information, stick to safe fonts so your message remains clear and accessible everywhere.
3. Think of custom fonts as seasoning, not the main dish. They enhance your design but shouldn’t be the only element you rely on. Always review and approve the fallback look (often Arial, Georgia, or Times New Roman) before campaigns go live. If brand consistency is essential, you may use images for headlines, but keep in mind that images do not resize as smoothly as text and reduce accessibility.

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Points to Remember

• By default, our system applies a predefined font and fallback fonts to ensure consistent rendering.
• If you want to override these defaults, you can upload your fonts through the Brand Kit and set a custom fallback font. Your selected fallback font will be applied and displayed in the email when configured.
• Custom fonts are your special brand typefaces, while safe fonts like Arial, Georgia, Times New Roman, and Verdana act as universal backups that display everywhere.
• Support for custom fonts is mixed; Apple and Mac apps typically render them correctly, while Gmail, Yahoo, and Outlook on Windows do not.
• The best approach to ensuring consistency is to set smart fallback stacks, test thoroughly across devices, and ensure that your emails look polished no matter where they are opened.