What is CaudalGhost
CaudalGhost shows you how much network traffic each application and interface on your Linux machine is using: live, second by second, with history saved along the way. Everything happens right on your machine.
What it solves for you
Section titled “What it solves for you”- Clarity: see which app is eating your bandwidth right now.
- Memory: history never expires (no automatic purge yet); look back weeks or months.
- Detail: breakdowns by application, by interface, and by remote server (hostname).
- Peace of mind: your data stays on your machine. It observes — it never interferes.
What it’s NOT
Section titled “What it’s NOT”- Not a firewall. It doesn’t block, cut, or control traffic. It only measures it and makes it visible.
- Not just a snapshot of the moment: CaudalGhost keeps a history, which never expires (no automatic purge yet).
- Not a cloud service: no accounts, no telemetry — everything lives on your machine.
How it works, in one line
Section titled “How it works, in one line”eBPF measures traffic per app and interface → the daemon (running with privileges, sudo, solely to read from the kernel) logs it in SQLite → you query it through three faces: the GUI (caudalghost-gui), the CLI (caudalghost), or the full-screen live dashboard in your terminal (caudalghost live).
The technical “how” lives in the guides below; what matters is that it measures, it doesn’t interfere, and nothing it logs ever leaves your machine.
The nine principles
Section titled “The nine principles”CaudalGhost isn’t a list of loose features: it’s a stance on how a network should be measured. Nine principles define it:
- Focused on your machine — it measures the machine it runs on — desktop or server — and only that one.
- Per app and per host — every byte, tied to its program and to the server or local machine it talks to.
- Indefinite history — the daily layer is kept for good; memory doesn’t expire (no automatic purge yet).
- Lightweight by design — a watcher that stays out of your machine’s way.
- Never blocks — purely observational: it measures, it doesn’t interfere.
- Private and local — your data stays on your machine; nothing phones home.
- Three faces, one source — CLI, TUI, and GUI over the same daemon.
- Frugal inside — little code, few dependencies, nothing spare.
- Free and auditable — AGPL-3.0, open source top to bottom.
License
Section titled “License”CaudalGhost is free software under AGPL-3.0. The code is auditable; see Contributing and license.