The Salesforce Mobile App runs the same metadata as desktop Lightning Experience but with a different rendering layer and a different set of available components.
Key differences:
- Layout: mobile uses Compact Layouts to control which fields show in highlight views (the top of a record on a phone). Compact Layouts are smaller and prioritise the most-needed fields.
- Page composition: Lightning Record Pages can be built specifically for Phone form factor in Lightning App Builder. You can hide entire components, swap layouts, and reorder tabs for phone vs desktop.
- Action buttons: the Mobile and Lightning Actions section of the page layout (or the Actions component on a Lightning Record Page) determines which Quick Actions appear in the mobile UI. Some standard buttons (e.g., complex workflows) are desktop-only.
- Custom UI: most Lightning Web Components work on mobile, but some
aura:componentfeatures and certain third-party components don't render properly. You always test custom UI on actual mobile devices. - Offline: mobile has limited offline support via the Briefcase feature and Mobile Configurations, but the offline experience is much narrower than desktop.
- Notifications: push notifications work on the mobile app via Notification Builder and Connected App push settings — desktop uses email or in-app notifications instead.
- Performance: mobile is often the constraint — pages with heavy related lists or unbulkified flows feel fine on desktop and crawl on a phone.
A common mistake: admins build the Lightning Record Page for desktop, never check the phone form factor, and discover users see a chaotic stack of every component as a single column. Always preview the Phone form factor in App Builder before assigning.