Types
Sentence case: Capitalize the first word of the text element, as well as any proper nouns.
Title case: Capitalize every word in the text, except:
- Articles (a, an, the), unless they appear as the first word in a sentence
- Coordinating conjunctions (and, or)
- Prepositions (for, by, from), except the first or last word in a sentence
- Infinitives (to, in, an)
To check if you're using title case correctly, put your text into Capitalize My Title using the AP setting.
Guidelines
For desktop browsers, Android browsers, and websites:
Default to sentence case to support scanning and strike a friendlier tone. Sentence case headlines and buttons.
While sentence case is the default, there are a few exceptions:
|
Type |
Casing |
|
Acronyms |
All caps (URL, etc.) |
|
Android snackbars |
All caps (UNDO, DELETE) |
|
Brands and products |
Title case proprietary names (Mozilla, Firefox, etc.) |
|
Context menus within operating systems |
Title case |
|
Feature names |
Casing will depend on the feature. (See the word list). We don’t capitalize features such as “new tab,” “shortcuts,” or “passwords,” because they’re not proprietary. |
|
Global Operating System menu bar (desktop) |
Title case |
|
Tab audio state |
All caps (PLAYING, MUTE TAB, MUTED) |
For the Firefox iOS browser:
Apple’s Human Interface Guidelines leave it up to the individual app to choose the casing approach that’s right for your product. The Firefox iOS browsers use title case in many text elements, largely to align with iOS patterns and also based on some historical decisions.
The following elements use sentence case:
- Body copy
- Text links
- Headlines on first run onboarding.* This is a brand-forward moment, and our brand leans informal. The headlines here are short, complete sentences, so title case makes them feel jumpy. Using sentence case aligns with what users see in the app store before onboarding and matches the desktop and Android first-run experiences.
The following elements use title case:
- Menus: App menu, edit menus, context menus, share sheet menus, settings labels
- Buttons, both System and Firefox-generated
- Bottom sheet titles*
- Headlines on homepage*
- Settings labels
- Messages*: if the title is a sentence fragment, use title case and no ending punctuation. If the title is a complete sentence, use sentence case plus ending punctuation. This applies to:
- Alerts
- Contextual Feature Recommendations (CFRs) headlines
- Information card headlines
- Error Card titles
- Empty state titles
- Toasts*
- Notification titles are an exception in that these are always title case, even if a complete sentence.
The following elements use all caps: Section labels in Settings
*2025 clarification or change