# LuLu vs Radio Silence

Published January 1, 2026 · Updated August 10, 2026

LuLu and Radio Silence are both firewall on a Mac, so the pick depends on workflow. Install LuLu when you want the source and a host rule at no charge. Buy Radio Silence when a quiet whole-app block list is the job. As of October 2026, both install with brew install --cask lulu and brew install --cask radio-silence.

There is no single score. LuLu 4.5.1 is the free open-source tool with prompts and a remote-address rule. Radio Silence 3.4 is the $9 tool that blocks whole apps, skips pop-ups, and shows a real-time connection list. The scores above are the word Unscored on purpose.

## Head to head

| Factor | LuLu | Radio Silence |
| --- | --- | --- |
| Price | Free | Free |
| Open Source | No | No |
| Replaces | Little Snitch ($65) | — |
| Best for | firewall, network, privacy | radio silence |
| Install | brew install --cask lulu | brew install --cask radio-silence |
| Category | Security & Privacy | System Utilities |

## LuLu

Open-source firewall to block unknown outgoing connections

Install: `brew install --cask lulu`

[LuLu on Bundl](https://bundl.run/apps/lulu)

## Radio Silence

Network monitor and firewall

Install: `brew install --cask radio-silence`

[Radio Silence on Bundl](https://bundl.run/apps/radio-silence)

## Features

- **Price and trial.** LuLu costs nothing. Radio Silence is $9 with a trial and a 30-day refund.
- **Source code.** Only LuLu's page states that the firewall is open source.
- **How a block is scoped.** LuLu documents a host or domain field. Radio Silence documents a whole-app block.
- **Prompts.** LuLu asks, unless you turn on Passive mode. Radio Silence is built not to ask.
- **Monitor.** Both show current connections. Neither app describes a multi-month history chart.
- **Current build.** Both vendors publish a current Mac build.

## FAQ

### Is LuLu or Radio Silence free?

LuLu is free and open source. Radio Silence costs $9, with a free trial and a 30-day money-back guarantee.

### Which one asks before a new connection?

LuLu alerts on a new unauthorized outgoing connection. Passive mode can silence those alerts. Radio Silence has no annoying pop-ups: you block apps yourself.

### Can either app block a single domain?

A LuLu rule can name a remote address or domain and a remote port. Radio Silence blocks whole apps, including child processes, and does not describe a per-host allow rule.

### What versions were current on 2026-10-14?

LuLu's download line was v4.5.1 for macOS 10.15 or later, and GitHub marked 4.5.1 Latest on 2026-08-05. Radio Silence's download page listed Version 3.4 for macOS 10.15 and newer, with Tahoe install notes and no calendar date for that build.

### Do the vendors publish memory use?

Neither vendor publishes a memory or CPU figure. Radio Silence calls the app lightweight and claims no performance effect, without a measurement.

## Sources

- [LuLu by Objective-See](https://objective-see.org/products/lulu.html)
- [LuLu releases on GitHub](https://github.com/objective-see/LuLu/releases)
- [Radio Silence homepage](https://radiosilenceapp.com/)
- [Radio Silence download](https://radiosilenceapp.com/download)

## Related

- [Little Snitch vs LuLu](https://bundl.run/compare/little-snitch-vs-lulu)
- [Little Snitch vs Radio Silence](https://bundl.run/compare/little-snitch-vs-radio-silence)

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