Fluid is a macOS utility that packages any URL into a self-contained, native-feeling desktop application — its own Dock icon, its own App Switcher entry, its own set of preferences — all without shipping a line of Electron.
What is Fluid?
Fluid creates what its developer calls Site Specific Browsers (SSBs): lightweight macOS applications that house a single web service inside a dedicated WebKit shell. Give Fluid a URL and a name, point it at an icon you like, and in under a minute you have a double-clickable app sitting in your Applications folder. Gmail becomes its own thing. Notion becomes its own thing. Figma, Linear, Superhuman — anything you live in all day can graduate from buried browser tab to first-class citizen on your Mac.
I started using Fluid because tab sprawl was making me miserable. My browser windows were each competing for screen space with tools that deserved a dedicated window and a Cmd-Tab slot. The moment I moved Notion and my project tracker into their own Fluid apps, my browser tab count halved overnight and my context-switching cost dropped with it.
What does Fluid do best?
Fluid's real superpower is focus isolation. Each SSB it generates runs as a separate process — no shared cookie jar, no cross-contamination with your browsing session, no "which tab is making that sound?" detective work. Because the shell is pure WebKit, the rendering is fast and memory-efficient compared to spinning up a second Electron-based browser window just to isolate a service.
- Custom Dock icons — drag in any PNG or ICNS file; the community maintains icon packs for hundreds of popular services.
- Separate sessions — log into your personal Gmail in the browser and your work Gmail in a Fluid app simultaneously, with zero conflicts.
- Menu-bar mode — the paid upgrade lets any Fluid app live in the menu bar instead of the Dock, ideal for always-on tools like Slack or a time-tracker.
- Userscripts and userstyles — inject custom JavaScript and CSS into your SSB to adjust the layout or behaviour of any web service without touching a browser extension.
- Whitelist navigation — lock the SSB to its own domain and push every external link back to your default browser automatically.
Is Fluid free?
Fluid is free to download and use for basic SSB creation. A one-time paid upgrade unlocks the premium tier: menu-bar apps, userscript injection, and persistent cookies with advanced whitelist rules. The upgrade price is modest enough that most power-users who spend real hours inside web apps consider it an obvious call — there is no subscription, no annual renewal, just a single purchase that persists across updates.
Who should use Fluid?
Fluid is built for Mac users who live inside one or two specific web services all day and want them to feel like native apps rather than pinned tabs. Think: a freelancer with separate client workspaces in Notion, a support engineer who needs Zendesk to stay always on top, a developer toggling between a GitHub project board and a Linear backlog. If a browser-native PWA already satisfies you, you may not need it — Safari on Ventura and Sonoma can pin a site to the Dock — but if you have ever wished your web tools had a dedicated Spotlight entry and a Cmd-Tab icon that does not vanish when you close the browser, Fluid is the cleaner answer.
Fluid is less suited to people who want a single window hosting ten services at once. For that aggregation pattern, Franz or Rambox bundle multiple services under one roof. Fluid is strictly one site per app; the philosophy is isolation, not aggregation.
How does Fluid compare to Unite and native PWAs?
Unite is the closest direct rival — it also builds SSBs, adds more granular macOS chrome-hiding for a near-native look, and sits at a comparable price. Fluid predates Unite by years and carries a larger community of userscripts and icon sets. Safari's built-in "Add to Dock" feature works for casual use but strips away customisation headroom: no userscript support, limited session isolation, and the shell still reads as a browser under the hood. Chrome's PWA implementation is more capable but anchors you to Chrome's engine and memory overhead. Fluid's WebKit base keeps each SSB lighter, better aligned with macOS privacy controls, and wired into the system keychain without extra configuration.
