NetMeter

A small, quiet network usage monitor for the macOS menu bar.
Live rate, any time range, per-app usage — and how much of your data plan is gone.

Website · Install · Features · Screenshots · Configuration · CLI · Uninstall · Changelog

Project entry points

• The website runs the real panel UI in the browser on made-up traffic (site/).

• Download a release or use the Homebrew tap.

• netmeter-core contains sampling, persisted state, formatting, and statistics.

• The desktop crate connects the menu-bar app, per-app sampling, and CLI.

• Signing notes explain the current macOS distribution setup.

The core and desktop shell are separate, so the measurement/reporting code can be read independently of the UI. Installation, screenshots, and measurement behavior are documented below.

Why another one of these

Stats and iStat Menus already show network traffic. Two things are different here:

• It is built around a data cap. Set your plan's size and reset day, and the panel is about how much of it is gone and when it renews — with notifications as you cross the thresholds you picked.
• It needs no privileges. No Accessibility permission, no root, no kernel extension, no network filter. It reads the same per-interface counters Activity Monitor does, and nettop for per-app numbers.

Features

Live rate	Download and upload in the panel, updated every second
Any time range	1H / 6H / 12H / 24H / 7D / 30D / Today / Cycle, an explicit From–To picker, or drag across the graph to zoom
Per app	The busiest processes since launch, or per-interface totals for the selected range
Data cap	Progress against your plan, a reset day, and threshold notifications
Menu bar	A quiet activity glyph, or the live rate, or the cycle total — your choice
Looks how you like	Light or dark, or follow the system, with a panel opacity slider
Starts with you	Optional launch at login, so the totals have no gaps
Private	A SQLite file on your machine. No accounts, nothing uploaded

Install

Homebrew:

brew tap omerdikyol/netmeter
brew trust omerdikyol/netmeter   # Homebrew 7 asks for third-party taps to be trusted
brew install --cask netmeter

Or download NetMeter-macos-universal.dmg from Releases, open it, and drag NetMeter into Applications. There is a .zip too, if you prefer.

Releases are signed with a Developer ID certificate and notarized by Apple, so the app opens normally — no Gatekeeper workaround. Builds up to and including 0.1.0 were unsigned: if you have one of those, right-click it and choose Open. SIGNING.md covers how the signing works.

From source:

git clone https://github.com/omerdikyol/netmeter
cd netmeter
cargo build --release
packaging/macos/bundle.sh
open dist/NetMeter.app

Requirements: macOS 13 or newer, Apple silicon or Intel. Building needs Rust 1.80+.

Using it

NetMeter sits in the menu bar as a small activity glyph so it stays out of the way. Left-click it for the panel; right-click for a short menu with Settings and Quit.

The panel is four things: the live rate, the graph with its range control, today's and this cycle's totals, and the usage list. The gear in the footer opens settings.

If the icon does not appear

Menu bar managers such as Ice or Bartender hide new items by default — they are moved off-screen until you reveal them. If NetMeter is running but you cannot see it, open that manager and move NetMeter to the always-visible section.

Screenshots

Choosing a time range	Settings

Configuration

Everything is settable in the panel, but it is just a TOML file, created on first run. netmeter config prints the paths and the current contents.

[general]
sample_interval_ms = 1000
launch_at_login = false
menu_bar = "icon"      # icon | rate | total
unit = "auto"          # auto | binary | decimal

[appearance]
theme = "system"       # system | light | dark
opacity = 0.72

[plan]
enabled = true
cap_bytes = 50000000000
cycle = "monthly"      # weekly | monthly
reset_day = 15
warn_at = [0.8, 1.0]

History is a SQLite file beside it, pruned to 90 days. Note that NetMeter only samples while it is running, so the totals cover that time — the panel says since when.

The command line

The same engine, without the tray:

netmeter status                             # per-interface counters right now
netmeter report --range today               # usage today
netmeter report --range cycle               # usage this billing cycle
netmeter report --from 2026-09-01 --to 2026-10-01
netmeter report --iface en6 --json          # one interface, machine readable
netmeter sample --interval 1                # live rate in the terminal

report and sample are read-only: they never touch the stored history.

How it works

• No bundled browser. The tray is native (tray-icon + tao); the panel is drawn by the system webview, so nothing like Chromium ships with the app.
• Counters, not guesses. Per-interface bytes come from sysinfo (getifaddrs on macOS). Interface counters restart on reboot or link flap, so a value that goes backwards is treated as a reset — NetMeter never reports a negative or inflated delta.
• Per-app usage is nettop sampled every few seconds and diffed, so those numbers count only what happened while NetMeter was running.
• Small. One binary plus the system webview. No background service, no helper, no login item unless you ask for one.

Uninstall

brew uninstall --cask netmeter            # add --zap to remove your history too

Or just drag NetMeter.app to the Trash. Configuration and history live in ~/Library/Application Support/dev.omerdikyol.netmeter.

macOS only, for now

The panel renders through wry, which needs a GTK event loop on Linux that this app does not set up yet, and Windows has never been exercised. Rather than claim three platforms and ship one, this release says macOS and means it. crates/netmeter-core — sampling, storage, statistics, configuration — is platform-neutral and would be the base for other front ends.

Development

The panel can be shown without clicking the tray icon, which is handy while working on the UI:

NETMETER_PREVIEW_PANEL=1 cargo run                 # open the panel on launch
NETMETER_PREVIEW_PANEL=1 NETMETER_PREVIEW_DELAY_MS=4000 cargo run
                                                   # ...a few seconds later
NETMETER_PREVIEW_SHEET=1 cargo run                 # with the range picker open
NETMETER_PREVIEW_SETTINGS=1 cargo run              # on the settings screen
NETMETER_KEEP_OPEN=1 cargo run                     # never dismiss on focus loss
NETMETER_DEMO=1 cargo run                          # draw invented data, not yours

NETMETER_DEMO is what the screenshots in this README were taken with: it makes the panel ignore the real state and draw a fixed, made-up dataset, and squares its corners at full opacity so a capture contains nothing but panel pixels.

crates/netmeter-core   sampling, storage, stats, config (no UI; unit tested)
crates/netmeter        tray app, panel host, per-app sampler, CLI
ui/index.html          the panel itself (HTML/CSS/JS, no build step)
packaging/macos        Info.plist, bundle, signing and icon scripts
packaging/homebrew     the cask; copy it to the homebrew-netmeter tap on release

Contributions are welcome. cargo test and cargo clippy --all-targets -- -D warnings should both be clean before a pull request.

Roadmap

• Sampling, storage and reporting core, with a CLI
• Menu bar app and the panel
• Per-interface and per-app views, any time range
• Data cap, reset cycle and threshold notifications
• Universal packaging, Homebrew cask and a generated icon
• Signed and notarized releases
• Linux and Windows front ends

License

Dual-licensed under either of MIT or Apache-2.0, at your option.

The bundled JetBrains Mono font (used only when the menu bar shows a number) is under the SIL Open Font License 1.1 — see assets/fonts/OFL.txt.