eul
macOS status monitoring app
eul — Official Website
Quick Take: eul
eul is a triumph of modern Mac app development. It proves that powerful system monitoring doesn't need to be ugly, expensive, or resource-heavy. While it lacks the deep historical logging of iStat Menus and the granular fan control of dedicated tools, it excels at what it promises: a beautiful, native, and lightweight status monitor. For 95% of users, it provides exactly the right amount of information in a package that respects the design of macOS. It is an essential utility for developers and power users alike.
Best For
- •Design-conscious users and developers.
What is eul? — Complete Guide for Mac Users in 2026
In the world of macOS system monitoring tools, eul stands out as a distinctively modern, lightweight, and open-source utility designed specifically for the era of macOS Big Sur and beyond. Created by developer Gao Sun, eul was built from the ground up using Apple's SwiftUI framework, ensuring that its aesthetics smoothly blend with the native macOS interface. Unlike legacy monitoring tools that often rely on outdated codebases or heavy graphical assets, eul uses the efficiency of Swift to deliver real-time data on CPU, memory, battery, disk usage, and network activity without draining system resources itself. As of 2026, eul remains a favorite among purists and developers who prioritize open-source transparency and aesthetic integration. It is fully compatible with the latest Apple Silicon chips (M-series, including M3 and M4) and adapts perfectly to the notch design on modern MacBook Pros. The application differentiates itself by offering a clean, 'Apple-like' experience that feels less like a third-party add-on and more like a built-in feature of the operating system. For users who find iStat Menus too expensive or complex, and who want a free, privacy-respecting alternative that sits quietly in the menu bar or Notification Center, eul is the definitive choice. Its support for desktop widgets and dark mode further cements its utility in modern workflows, making it an essential install for anyone who wants to keep a finger on the pulse of their Mac's performance.
Install with Homebrew
brew install --cask eulDeep Dive: eul's SwiftUI Architecture
eul represents a shift in how macOS menu bar apps are constructed. Traditionally, these apps were built using Objective-C or AppKit, requiring significant boilerplate to handle UI rendering, especially for dark mode compatibility and high-DPI (Retina) displays. eul bypasses this legacy debt by adopting SwiftUI, Apple's declarative UI framework. This choice results in a binary that is remarkably small and a UI that is inherently responsive. Because SwiftUI uses the GPU for rendering, eul's animations and graphs are fluid without taxing the main CPU thread, ensuring that the act of monitoring the system doesn't degrade system performance.
Key Features
Native SwiftUI Design & Dark Mode Support
One of eul's defining characteristics is its underlying architecture built entirely with SwiftUI. This isn't just a technical detail; it translates to a user interface that respects macOS design guidelines more strictly than almost any competitor. In 2026, where macOS interfaces have become increasingly fluid and unified, eul looks perfectly at home. It automatically respects the system's appearance settings, switching smoothly between Light and Dark modes without user intervention. The text rendering, spacing, and iconography align perfectly with the SF Symbols used by Apple, ensuring that when you glance at your status bar, eul looks like it was shipped with the OS. For users sensitive to UI consistency, this feature eliminates the visual jar ring often caused by ported or cross-platform applications.
Granular CPU & GPU Monitoring
eul provides a comprehensive breakdown of processor activity that goes beyond simple percentage bars. It visualizes usage on a per-core basis, which is particularly insightful for users on high-core-count Apple Silicon machines. The monitor separates System and User load, allowing you to identify exactly what is consuming your resources. Additionally, it taps into the system's thermal sensors to display real-time CPU and GPU temperatures. For creative professionals rendering video or 3D assets, seeing the correlation between GPU load and thermal throttling in real-time is invaluable. The interface allows you to toggle between a compact mini-graph in the menu bar or a detailed list view in the dropdown menu, offering flexibility based on screen real estate.
Advanced Battery & Power Analytics
For MacBook users, eul offers a battery monitoring suite that rivals paid dedicated utilities. Beyond the standard percentage remaining, it exposes deep system data including the battery's current condition (health), total cycle count, and design capacity versus actual maximum capacity. In 2026, with aging batteries in older M1/M2 laptops, this feature is critical for determining when a service is needed. Also, eul displays the current power source and amperage draw/charge rates in watts. This allows users to verify if their charger is delivering the expected power delivery (PD) speeds or if a specific cable is bottlenecking the charge time. It creates a complete picture of your portable power hygiene.
Real-Time Network Traffic Monitor
Understanding network throughput is essential for remote work and streaming, and eul puts this data front and center. It tracks real-time upload and download speeds, displaying them directly in the menu bar or within the dropdown panel. Users can view their local IP address and identifying public IP information with a single click—a frequent need for network administrators and developers. The tool supports physical, Wi-Fi, and Thunderbolt bridge interfaces, automatically detecting the active connection. A standout capability is the visual graph of network history, which helps diagnose intermittent connection drops or bandwidth throttling by ISPs during large file transfers or video calls.
Fan Speed & Thermal Management
While Apple Silicon runs cool, thermal management remains a priority for sustained performance, and absolutely critical for Intel-based legacy Macs still in use. eul interfaces with the System Management Controller (SMC) to read fan speeds (RPM). It displays the current speed against the minimum and maximum operational limits of the specific hardware fans. This feature gives users immediate feedback on the auditory environment—letting you know if your fans are ramping up before you even hear them. It pairs this data with sensor readings from various thermal zones (CPU Proximity, GPU, Battery, Memory), helping users understand *why* the fans are spinning up, whether it's a compile job or a blocked vent.
Bluetooth Peripheral Battery Tracking
Managing the battery life of peripherals is often a friction point in the macOS experience, requiring users to dive into System Settings or obscure menus. eul centralizes this by pulling battery levels for connected Bluetooth devices directly into its status panel. This supports Apple's ecosystem—Magic Mouse, Magic Keyboard, Magic Trackpad, and AirPods—as well as select third-party devices. By having a quick-glance percentage for your mouse or keyboard, you can prevent the frustration of a dead peripheral during a meeting. The integration is lightweight and updates dynamically as devices connect and disconnect, removing the need for separate battery monitor apps.
Who Should Use eul?
1The Full-Stack Developer
Meet Alex, a developer running Docker containers and compiling large React Native apps on a MacBook Pro. For Alex, system resources are a budget that needs balancing. Using eul, Alex configures the menu bar to show only CPU load averages and RAM pressure. When a build starts to crawl, a quick glance at eul's dropdown reveals if a Docker container has hung and is consuming 100% of a specific core, or if memory swap usage has spiked, indicating a need to close Chrome tabs. The network monitor is equally crucial, confirming that npm packages are actually downloading during a stall. eul allows Alex to diagnose bottlenecks instantly without breaking flow to open Activity Monitor.
2The Mobile Professional
Sarah is a freelance writer and consultant who works almost exclusively from coffee shops and airport lounges. She relies on her MacBook Air's battery to last a full 10-hour day. She uses eul primarily for its power analytics. By keeping the wattage draw visible in her menu bar, she can instantly see how much power her current workflow consumes. If she sees the draw spike from 5W to 15W, she checks eul to find a rogue background process or a heavy browser tab. She also uses the network widget to verify that the airport Wi-Fi is stable before attempting to upload large PDF proofs. For Sarah, eul is a survival tool for battery anxiety.
3The Minimalist Designer
Liam is a UI designer who prides himself on a clean, distraction-free workspace. He despises the cluttered, colorful icons of traditional status bar apps. He chooses eul because of its native SwiftUI rendering and monochrome icon set that blends perfectly with his dark mode setup. He disables the menu bar text for most metrics, relying instead on eul's notification center widgets. When he needs to check his RAM usage while running Photoshop and Illustrator simultaneously, he simply swipes left on his trackpad to peek at the eul widgets, then swipes back to work. This setup keeps his screen real estate dedicated purely to pixels, not metrics.
4The Legacy Mac Enthusiast
Elena manages a small fleet of older Intel-based iMacs for a non-profit. These machines are prone to overheating and thermal throttling. Elena installs eul on every machine to monitor fan speeds and thermal sensors. The app allows her to quickly identify which machines need physical cleaning (dust in vents) by correlating high idle temperatures with maxed-out fan speeds. When a user complains of slowness, she checks eul to see if the CPU is throttling due to heat. The open-source nature of eul means she can deploy it across all machines without worrying about licensing fees, extending the useful life of the organization's hardware.
How to Install eul on Mac
Getting eul up and running is straightforward. Since it is open-source software, you have the flexibility to install it via a package manager or a direct download. Here is the most efficient method for 2026.
Install via Homebrew (Recommended)
The easiest way to install and maintain eul is via Homebrew. Open your Terminal app (Command + Space, type 'Terminal') and paste the following command: `brew install --cask eul`. This handles the download and places the app in your Applications folder automatically.
Launch and Grant Permissions
Open eul from your Applications folder. On the first launch, macOS may ask for permission to access certain hardware stats. You may simply click 'Open'. Unlike some competitors, eul requires minimal permissions, but ensures you allow it if prompted for network or location (for Wi-Fi SSID) access.
Configure Component Visibility
Upon launching, you will see a row of new icons in your menu bar. Right-click on any eul item or open the app settings (Preferences) to toggle which components (CPU, Battery, Fan, etc.) you want visible. You can drag and drop them to rearrange the order.
Enable Launch at Login
To ensure monitoring is always active, go to the eul Preferences menu (cmd + ,), navigate to the General tab, and check the box for 'Launch at login'. This ensures your stats are ready the moment your Mac boots up.
Pro Tips
- • If you prefer not to use Homebrew, you can download the latest release directly from the GitHub releases page and drag the .app file into your Applications folder.
- • For accurate network SSID reading on macOS Sequoia and later, you must grant 'Location Services' permission to eul in System Settings.
- • If you are on an older Intel Mac, ensure you install the helper tool if prompted to read fan speeds effectively.
- • Use the 'Update' feature within the app or run `brew upgrade --cask eul` periodically to get new features.
- • eul is also available on the App Store, though some features are disabled due to SMC call restrictions and the version may be outdated.
Configuration Tips
Declutter with Single-Line Text
By default, eul might show icons and two lines of text (e.g., download and upload speed). In the preferences, look for the 'Text Display' options. Switching to single-line mode or icon-only mode saves massive amounts of horizontal space in the menu bar, which is vital for MacBook users with a camera notch that limits available space.
Optimize Refresh Rates
In the General settings, you can adjust the refresh interval. While '1 second' looks cool, it consumes more battery. For a laptop on the go, set the refresh rate to 3 or 5 seconds. This provides a reasonable overview of system health without the monitoring tool itself becoming a battery drainer.
Customize the Widget Stack
eul supports macOS Notification Center widgets. Instead of crowding your menu bar, disable the less critical monitors (like Disk usage or Bluetooth) from the menu bar and add them as Small or Medium widgets in your Notification Center. This keeps them accessible via a swipe but hidden during deep work.
Language and Unit Localization
Ensure you set your preferred temperature unit (Celsius vs Fahrenheit) immediately in the settings to match your mental model. Additionally, eul has excellent community localization; if English isn't your primary language, check the Language dropdown—it supports over 20 languages thanks to community contributions.
Alternatives to eul
While eul is fantastic, the Mac ecosystem is rich with monitoring tools. Here is how it stacks up against the heavy hitters.
iStat Menus
iStat Menus is the gold standard for Mac monitoring, offering deeper history graphs, weather integration, and extreme customizability. However, it is a paid commercial product. Choose iStat Menus if you want historical data logging (charts going back 30 days) and weather forecasts. Choose eul if you want a free, open-source, lightweight alternative that covers the 90% of features most users actually need without the cost.
Stats (by exelban)
Stats is eul's closest rival—another open-source, Swift-based monitor. Stats generally offers slightly more granular control over sensors and arguably more frequent updates than eul. The choice often comes down to aesthetic preference; eul feels more like a native SwiftUI demo, while Stats feels a bit more dense and data-heavy. If eul feels too simple, try Stats. If Stats feels too cluttered, stick with eul.
Activity Monitor (Native)
The built-in Apple Activity Monitor is powerful but requires opening a separate window. It is a diagnostic tool, not a status monitor. eul replaces the need to keep Activity Monitor open for casual checking. Use Activity Monitor for deep process killing and energy impact analysis, but use eul for the constant, glanceable situational awareness that Apple's native tool lacks.
Pricing
eul is completely free to use. It is licensed under the MIT License. There are no in-app purchases, no subscriptions, and no locked 'Pro' features. The developer, Gao Sun, accepts donations via Ko-fi or GitHub Sponsors, but payment is entirely optional and does not affect functionality.
Pros
- ✓Native SwiftUI interface blends perfectly with macOS.
- ✓Completely free and open-source (MIT License).
- ✓Lightweight resource footprint compared to Electron apps.
- ✓Supports Big Sur+ Notification Center widgets.
- ✓Comprehensive battery health and cycle count data.
- ✓Dark mode and localization support out of the box.
Cons
- ✗Less historical data retention than iStat Menus.
- ✗Fan control is monitoring-only (cannot manually set speeds).
- ✗Update frequency can be sporadic depending on maintainer availability.
- ✗Menu bar spacing can sometimes be tricky on notched MacBooks.
Community & Ecosystem
eul thrives on GitHub, where a community of developers contributes translations, bug fixes, and feature requests. Because it is written in Swift and SwiftUI, it serves as a learning resource for many aspiring Mac developers. The project has garnered thousands of stars on GitHub, indicating a healthy user base. Issues are generally tracked publicly, and while it is largely a solo-developer project, the open nature allows forks and community patches to keep it alive even if the main development slows down.
Video Tutorials
Getting Started with eul
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Frequently Asked Questions about eul
Our Verdict
eul is a triumph of modern Mac app development. It proves that powerful system monitoring doesn't need to be ugly, expensive, or resource-heavy. While it lacks the deep historical logging of iStat Menus and the granular fan control of dedicated tools, it excels at what it promises: a beautiful, native, and lightweight status monitor. For 95% of users, it provides exactly the right amount of information in a package that respects the design of macOS. It is an essential utility for developers and power users alike.
About the Author
Productivity & Workflow Analyst
Related Technologies & Concepts
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Sources & References
Key Verified Facts
- eul is built using Apple's SwiftUI framework.[cite-github-repo]
- The application is released under the MIT License.[cite-license]
- eul supports macOS Big Sur widgets and newer.[cite-features]
- It provides battery cycle count and health data.[cite-battery]
- It is available for installation via Homebrew Cask using 'brew install --cask eul'.[cite-install]
- 1Homebrew - The Missing Package Manager for macOS
Accessed May 6, 2026
- 2eul GitHub Repository
Accessed May 6, 2026
- 3eul MIT License
Accessed May 6, 2026
- 4eul README - Features and Requirements
Accessed May 6, 2026
- 5eul Battery Monitoring Feature
Accessed May 6, 2026
- 6eul Installation Instructions
Accessed May 6, 2026