LuLu vs Little Snitch vs FlowSense
Choose LuLu for a free outgoing firewall. Choose Little Snitch for connection alerts with a detailed network monitor. FlowSense adds service names inside app traffic, speed limits for those services and an AI guard.
Facts checked on 3 November 2026.
LuLu or Little Snitch?
LuLu, from Objective-See, is free and open source. It alerts on unknown outgoing connections and lets you allow or block them. Rules can cover a process or a remote endpoint and can expire. Its setup can allow Apple software and already installed apps, so check those choices if you expect prompts for everything.
Little Snitch combines connection alerts with a traffic monitor. It groups traffic by app, domain or country, shows a map and keeps up to twelve months of history. It also offers incoming rules and encrypted DNS.
If all you need is outgoing blocking, start with LuLu. If you want to investigate traffic over time in the same app, Little Snitch is worth comparing. Our full Little Snitch comparison covers its trial and licence terms.
Where FlowSense Fits
A process name does not always answer what a connection is for. A browser can be streaming video, sending a chat message and uploading telemetry at once. FlowSense names 800+ apps and services by reading connection handshakes, without decrypting traffic. Its tree goes application, service, hostname, connection. How the classification engine works.
| You Need | LuLu | Little Snitch | FlowSense |
|---|---|---|---|
| Blocking Targets | Processes and endpoints, free | Apps and destinations, paid with a demo | Classified services and hostnames in Full |
| Traffic Investigation | Connection alerts and rules | Monitor, map and history | Live service tree, charts and Today usage, free |
| Slow a Classified Service | Not listed on its site | Not listed on its site | Full |
| Price | Free | See vendor's order page | $29 once until 9 November 2026, then $49, for one Mac |
With FlowSense Full, you can block or slow a classified service, hostname or category, with schedules and expiry. Warden suggests actions for new connections. Ask mode waits for you; Auto acts on its own and is a Research Preview. MCP connections start read-only; enabling Allow Changes lets an AI app change rules. See all features.
FlowSense does not currently make rules against a Mac executable or process. Choose LuLu or Little Snitch if you need to deny all outgoing traffic from one installed app, including traffic the engine has not classified.
Who Should Stay on LuLu?
Keep LuLu if its rules already do the job, or if free, auditable source code matters most to you. There is no reason to replace a working firewall just to get different charts. You can evaluate FlowSense's free monitoring before deciding whether you need its paid controls.
Check Before Switching
FlowSense is Mac only: Apple silicon and macOS 14 or later. It requires an account even for Free and isn't sold in the EU, the UK, Iceland, Liechtenstein or Norway yet. The 7-day trial unlocks Full; afterwards watching remains free. Pricing and licence details.
Rules do not transfer automatically between these apps. Record the rules you depend on, test one filter change at a time, and check your essential apps before removing your existing setup.
Sources
LuLu and Little Snitch are trademarks of their respective owners. FlowSense is not affiliated with Objective-See or Objective Development.