The short answer
Slack is slow because it is an Electron application. Electron bundles a full Chromium web browser and a Node.js runtime into every desktop app that uses it. When you open Slack, your computer is essentially booting a browser, loading a complex web application inside that browser, and then keeping all of it resident in memory for as long as Slack is running. That architectural choice explains why Slack can consume well over a gigabyte of RAM even when you have not typed a single message.
This is not a temporary outage or a server problem on Slack's end. It is the baseline cost of running the official client on any desktop.
What Electron actually does to your machine
Electron applications carry their overhead in a few distinct ways.
Memory usage. A Chromium renderer process has a significant baseline cost before any application logic runs. Slack layers its entire workspace UI — channels, threads, search, calls, app integrations — on top of that. The combined result is a memory footprint that competes with running a full browser with several tabs open, all day, every day.
CPU at idle. Electron apps commonly poll the DOM, run background JavaScript timers, and re-render parts of the UI even when you are not interacting with them. That steady background work keeps at least one CPU core partially busy and contributes to fan spin and battery drain on laptops.
Startup time. Launching Slack means initialising a Chromium instance, loading the JavaScript bundle, authenticating, and then rendering the workspace. On a mid-range machine this can take several seconds — noticeably longer than a native application doing equivalent work.
None of this is unique to Slack. Many popular desktop apps share the same architecture and the same tradeoffs. The difference is that a communication tool sits in the background all day, so even modest idle overhead accumulates into a real productivity and battery cost.
Is it a Slack outage or is it always this slow?
Before blaming Electron, it is worth ruling out a genuine service disruption. Slack publishes a real-time status page at status.slack.com. If message sending is failing, files are not uploading, or notifications are not arriving, a platform incident could be the cause. Those are transient and resolve on their own.
But if Slack feels generally heavy — takes a long time to appear after you click its icon, makes your system fan spin up, or shows high memory usage in Activity Monitor or Task Manager — that is the Electron baseline, not a temporary incident. Restarting Slack may give brief relief as memory is freed and caches are cleared, but the overhead returns as the session continues.
How a native client changes the picture
A native desktop client — one written in a compiled systems language against the operating system's own rendering primitives — does not carry a bundled browser. It starts faster because the operating system can load a smaller binary and begin work immediately. It idles closer to zero CPU because there is no JavaScript event loop running in the background. Its memory footprint is a fraction of what Electron requires, because it only allocates memory for the data it actually needs to display.
This is the reason msga exists. msga (Make Slack Great Again) is a free, open-source Slack client written in C++ with Qt6 — the same framework used by Telegram Desktop. It connects to Slack's APIs natively, without wrapping a browser around them.
| Characteristic | Official Slack (Electron) | msga (native C++/Qt6) |
|---|---|---|
| Runtime basis | Bundled Chromium + Node.js | Compiled C++, Qt6 framework |
| RAM at idle | 1 GB or more (typical) | Roughly 60–100 MB |
| CPU at idle | Noticeable background activity | Near 0 % |
| Startup time | Several seconds | Under one second |
| Platforms | Linux, macOS, Windows | Linux, macOS, Windows |
| License | Proprietary | GPL-3.0 (open source) |
What to expect from msga today
msga is in active development, and it is honest about that. Core messaging — reading and sending messages across channels and direct messages — works. The aim is a client that covers everyday communication without the resource cost of Electron.
Some of Slack's more advanced features (certain workflow automations, in-app calls, every third-party integration) are still on the roadmap. If your workflow depends heavily on those, it is worth checking the project's GitHub page to see the current state before switching fully. Many users find it practical to run msga for the bulk of their day and fall back to the browser-based Slack only for the edge cases that are not yet supported.
The practical takeaway
Slack feels slow today for the same reason it felt slow last year: running a communication app inside a browser has a cost that accumulates across every minute of your working day. A genuine service outage is worth checking, but if the slowness is structural, no amount of waiting or restarting will eliminate it.
A native client built for the task is the structural fix. msga is available for Linux, macOS, and Windows at no cost, with source code published under GPL-3.0. If the memory and CPU overhead of the official client is affecting your daily work, it is worth trying.