Live, byte by byte
See the flow right now: which app is uploading, which is downloading, in real time.
live flow See what flows
See what flows
through your network.
Discover how much every app and interface is using — live, with history kept forever. All on your machine.
observes · never interferes · your data, your machine
Pillars
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Live and historical
Right-now flow and long-term memory, in the same view.
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By app and by interface
Who is using what: every program, every network card, no guessing.
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Your data lives on your machine
Everything stays on your disk. It observes, it never interferes.
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Free and auditable (AGPL-3.0)
Open source code you can read, build, and verify yourself.
Privacy you can verify
We don't ask you to trust us blindly. Every promise has its proof.
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Your data lives on your machine
Everything it measures is stored in a local SQLite database on your disk. Nothing is transmitted.
Where your data lives → -
It observes, it never interferes
CaudalGhost measures traffic and makes it visible. It does not block it, redirect it, or control it.
How it works → -
Open source and auditable (AGPL-3.0)
You can read the code, build it, and verify the binary with its SHA-256 checksum.
Code · coming soon
How it works
You don't know which app is eating your connection, and finding out by hand is a chore. CaudalGhost measures in the kernel, attributes every byte to its program, and keeps it forever — without touching, blocking, or rerouting any of your traffic.
- eBPF Counts every byte in and out, without copying your traffic.
- daemon Attributes traffic to its app and interface, and aggregates it.
- SQLite Stores the history locally. Your data, your machine.
- GUI · CLI · TUI Watch it live or query the history however you prefer.
What you get to see
Clarity about your network, no jargon required: four views that answer "who's using what?"
History, kept forever
Compare today with last week. Every app's usage stays on record.
By app and by interface
Attributes every byte to its program and to the network card that moved it.
Which hosts it talks to
Resolves hosts (DNS) so you can see who each connection is talking to.
What it is, and what it is not
CaudalGhost exists to fill a gap: see — and remember — where your network traffic goes, without anything leaving your machine.
What it is
- An honest meter: it counts every byte and shows it to you.
- A memory of your usage: history per app and interface, kept forever.
- Local and yours: everything lives on your machine, open source (AGPL-3.0).
What it is not
- It's not a firewall: it doesn't block or control traffic — it only measures it and makes it visible.
- It's not just a snapshot: it keeps the history forever, on your machine.
- It's not a cloud service: no accounts, no telemetry: everything lives on your machine.
philosophy
Nine principles
CaudalGhost isn't a pile of loose features — it's a stance on how a network should be measured, with respect for your machine and your data. These nine pieces define it.
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Focused on your machine
It measures the machine it runs on — desktop or server — and only that one.
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Per app and per host
Every byte, tied to its program and to the server or local machine it talks to.
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Indefinite history
The daily layer is kept for good; memory doesn’t expire.
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Lightweight by design
A watcher that stays out of your machine’s way.
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Never blocks
Purely observational: it measures, it doesn’t interfere.
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Private and local
Your data stays on your machine; nothing phones home.
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Three faces, one source
CLI, TUI, and GUI over the same daemon.
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Frugal inside
Little code, few dependencies, nothing spare.
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Free and auditable
AGPL-3.0, open source top to bottom.
Download CaudalGhost
Two editions, one engine. No email, no account, no sign-up.
Desktop (.deb with GUI)
For your Linux desktop (Kubuntu, CachyOS…).
sudo apt install ./caudalghost_0.7.4-1_amd64.deb We're preparing the first public release — check back soon.
Verify checksum (SHA-256) →Headless server (.deb)
For your server or homelab (bare-metal Ubuntu Server).
sudo apt install ./caudalghost-server_0.7.4-1_amd64.deb We're preparing the first public release — check back soon.
Verify checksum (SHA-256) →Quick questions
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Is it a firewall? Will it block anything?
No. CaudalGhost only measures and displays your traffic. It doesn't block, filter, or redirect anything. It observes, it never interferes.
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Does it need sudo? Is it safe?
The daemon needs to start with privileges (sudo) to read the kernel counters (eBPF). It is open source and auditable; you can see exactly what it does.
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Where does my data live?
In a local SQLite database, on your own disk. Nothing is transmitted to any server. Your data, your machine.
Take back sovereignty over your network.
No clouds, no accounts, no surprises. Just you and your data.
Download CaudalGhost