A font stack is a list of fallback fonts used when a recipient’s device cannot load the first available font. Act-On’s composers use curated font stacks to preserve the look and structure of your design, even when a specific font isn’t supported on a device.
Each stack is built with visually compatible fonts - matched by shape and size - ensuring that your layout remains consistent and readable across browsers, devices, and email clients.
Quick Reference (Advanced Users) - Click to Expand
- A font stack defines how text should render if the primary font fails to load.
- Fallbacks ensure your design remains readable and consistent across devices.
- Act-On font stacks are chosen to match style, spacing, and weight as closely as possible.
- Use any font stack safely — each is optimized for broad compatibility.
Try it like this: Choose a Google-style font such as Open Sans or Montserrat for modern layouts. If the recipient’s device doesn't support the lead font, the fallback fonts in the stack will preserve spacing and style.
Why Font Stacks Matter
Not all devices support every font. Some email clients block web fonts entirely, while others substitute fonts unexpectedly. Font stacks ensure:
- Consistent branding when the primary font isn't available
- Reliable readability across devices and operating systems
- Stable layouts that don’t shift due to font substitutions
Available Font Stacks
These are the complete font stacks available in Act-On. Fonts earlier in the stack are preferred; later fonts act as backups.
- Andale Mono > monospace
- Arial Black > Helvetica Neue > Helvetica > sans-serif
- Arial Narrow > Helvetica Neue > Helvetica > sans-serif
- Bitter > Georgia > Times > Times New Roman > serif
- Book Antiqua > Book Antique > Georgia > serif
- Calibri > Helvetica > Arial > sans-serif
- Cambria > Geroria > Times > serif
- Century Gothic > CenturyGothic > AppleGothic > sans-serif
- Comic Sans MS > cursive > sans-serif
- Copperplate > cursive > serif
- Droid Serif > Georgia > Times > Times New Roman > serif
- Impact > Arial Black > cursive > sans-serif
- Lato > Tahoma > Verdana > Segoe > sans-serif
- Lucida Console > monospace
- Montserrat > Trebuchet MS > Lucida Grande > Lucida Sans Unicode > Lucida Sans > sans-serif
- Open Sans > Helvetica Neue > Helvetica > Arial > sans-serif
- Palatino Linotype > Palatino > Book Antiqua > Baskerville > Georgia > serif
- Roboto > Tahoma > Verdana > Segoe > sans-serif
- Source Sans Pro > Tahoma > Verdana > Segoe > sans-serif
- Symbol > cursive > sans-serif
- Terminal > monospace
- Ubuntu > Tahoma > Verdana > Segoe > sans-serif
- Webdings > sans-serif
- Windings > sans-serif
Best Practices
- Choose stacks that match your brand tone. Modern brands often use Montserrat, Open Sans, Lato, or Roboto.
- Favor widely supported fonts for long paragraphs. Serif fonts like Georgia or sans-serif fonts like Arial produce reliable results across email clients.
- Avoid highly stylized fonts for long-form content - they may render inconsistently.
- Test your design in multiple email clients using Preview and test sends.