eul is a free, open-source macOS menu bar app that surfaces real-time CPU, GPU, memory, network, fan, battery, and sensor data in a compact, always-visible overlay.
What is eul?
eul is a lightweight system monitor that lives entirely in your Mac's menu bar, giving you an at-a-glance dashboard of your machine's vital signs without ever opening Activity Monitor or a separate window. Written in SwiftUI, it feels native because it is — there are no Electron dependencies, no background daemons phoning home, and no subscription to manage.
The project is maintained on GitHub by Gao Sun and has attracted a healthy community of contributors. For a free utility, the polish is quietly impressive: the menu bar readout is configurable, the popover panel is crisp on both Retina and non-Retina displays, and the whole thing consumes a negligible slice of the very resources it watches.
What does eul do best?
eul excels at turning a wall of kernel telemetry into a scannable, human-readable snapshot you can check in half a second. Tap the menu bar icon and you get CPU utilisation broken down by core, GPU load, RAM pressure, disk activity, network throughput, fan RPM, and battery cycle count — all laid out in a clean popover without the noise of Activity Monitor's process list.
The CPU temperature readings are especially useful on MacBooks where sustained loads creep up silently. I've caught more than a few runaway background processes by glancing at eul mid-call rather than hunting through a full Activity Monitor session. The network pane is similarly handy when you suspect a sync client is hammering your connection during a video call.
- Per-core CPU breakdown — immediately shows whether a single core is pegged or all cores are loaded
- GPU utilisation — critical on M-series Macs where integrated GPU contention affects everything from Xcode previews to video export
- Memory pressure gauge — shows used, wired, compressed, and free RAM at a glance
- Fan and sensor readouts — surface temperatures and RPMs that Apple's own widgets never expose
- Customisable menu bar items — choose which stats appear inline vs. popover-only to keep clutter down
Is eul free?
Yes — eul is completely free and open-source under the MIT licence. There is no paid tier, no in-app purchase, and no "pro" unlock. You can install it via Homebrew Cask (brew install --cask eul) or download the DMG directly from the GitHub releases page.
Who should use eul?
eul is ideal for developers, video editors, and anyone who runs sustained workloads and wants passive awareness of system health without a dedicated monitoring window eating screen real estate. If you regularly compile large codebases, transcode footage, run local AI models, or keep a dozen browser tabs and Electron apps alive simultaneously, eul acts as a quiet co-pilot that flags thermal and memory pressure before it becomes a performance problem.
It is less suited to users who want historical graphs, alert notifications when thresholds are crossed, or the kind of deep process inspection you get from iStatistica Pro or Timing. For passive at-a-glance monitoring, though, its simplicity is a feature, not a gap.
What are the best eul alternatives?
The menu-bar monitoring space on macOS is well-served. iStatistica Pro is the premium benchmark — it adds historical logging, customisable widgets, and notification alerts for a modest one-time fee. Stats (also open-source, also free) is eul's closest peer and offers a few more chart styles and a slightly denser popover. MenuMeters is the long-time community favourite rebuilt for modern macOS. Apple's own Activity Monitor goes far deeper on process-level detail but requires a full window and provides no persistent ambient readout.
I keep eul installed alongside iStatistica Pro — eul for the minimal menu bar number, iStatistica for the occasional deep dive into historical load graphs before a client call.
How does eul compare to Stats?
Both eul and Stats are free, open-source SwiftUI menu bar monitors with overlapping feature sets. eul's design sensibility leans slightly more minimal — the popover is cleaner and less configurable, which means less time fiddling with preferences and more time actually working. Stats offers more chart-type options and a more granular sensor list on Intel Macs. On Apple Silicon, the difference narrows considerably; both tools surface the same M-series performance and efficiency core data. If you want something you can install and forget, eul wins on simplicity. If you enjoy tuning the display, Stats is worth a look.",
A note on Apple Silicon compatibility
eul runs natively on M1 through M4 chips and correctly reports the unified memory architecture — including the distinction between CPU-side and GPU-side memory pressure — which older monitors built for Intel sometimes misread or omit entirely.
