Why people search for a self-hosted Slack alternative
The motivation is almost always one of three things: data ownership, cost at scale, or resource consumption on end-user machines. These sound related, but they call for very different solutions.
Data ownership and compliance teams want message history stored on infrastructure they control, under retention policies they set, subject to jurisdictions they choose. No amount of tweaking a desktop client addresses this — you need to move off Slack's servers entirely.
Cost at scale teams are paying per seat on a SaaS plan and want to eliminate that line item. Again, this is a server-side problem.
Resource consumption teams are fine with Slack's servers and Slack's feature set, but find that the official Electron-based desktop app consumes an uncomfortable amount of RAM and CPU across a fleet of developer machines. This is a client-side problem, and replacing the client is all that is required.
Being clear about which category you are in is the most useful thing you can do before evaluating any tool.
Full server replacements: the landscape
If genuine data sovereignty is the goal, you are looking at platforms that run their own backend. The mature options in 2026 are well known:
| Platform | Protocol / backend | Self-host complexity | Slack feature parity |
|---|---|---|---|
| Mattermost | Proprietary (Go backend) | Medium — Docker or Kubernetes, PostgreSQL required | High for messaging; some enterprise features are paid |
| Rocket.Chat | Proprietary (Node.js + MongoDB) | Medium-high — resource-hungry at scale | High; video, threads, marketplace |
| Zulip | Proprietary (Python/Django) | Medium — well-documented installer | Different UX model (topics-first); good for async teams |
| Matrix / Element | Open federated protocol | Medium — Synapse or Dendrite server required | Lower out of the box; bridges to Slack exist but add complexity |
Each of these projects is legitimate and actively maintained. The honest caveat is that self-hosting any of them requires ongoing operational work: upgrades, backups, monitoring, and occasional incident response. For a small team without dedicated infrastructure staff, that cost can exceed what a Slack subscription would have cost.
There is also the migration problem. Moving years of Slack message history, integrations, bots, and workflows to a new platform is a significant project. Slack does provide a data export for paid plans, but import tooling on the receiving end varies considerably in quality.
When you do not need to replace the server at all
If your team is staying on Slack but the official desktop app is the pain point, a full server migration is solving the wrong problem.
The official Slack app is built on Electron — a bundled Chromium browser packaged as a desktop application. It works, and it supports every Slack feature, but it carries the memory and CPU overhead of a browser engine whether you need it or not. On machines with constrained RAM, or on Linux distributions where the app's integration with the system is poor, this overhead is noticeable.
This is the gap that msga fills. msga (Make Slack Great Again) is a native desktop client for Slack, written in C++ and Qt6 — the same framework used by Telegram Desktop. It connects to the standard Slack backend, so your workspace, history, channels, and permissions are all unchanged. The difference is purely in how the client is implemented: no bundled browser engine, no Electron overhead.
The practical result is that msga starts in under a second, idles near zero CPU usage, and uses a fraction of the memory the official app requires — in the range of 60–100 MB versus the 1–2 GB or more the official client can reach over a working day.
What msga is and is not
Honesty matters here. msga is open source under the GPL-3.0 license and is in active development. It is not a drop-in replacement for every Slack feature you might rely on.
It handles core messaging — reading and writing messages across channels and direct messages — and does so with a fast, native feel on Linux, macOS, and Windows. Some of the more complex Slack features (certain workflow automations, richer app integrations, video calls) are on the roadmap but are not all present in current builds. If your team's workflow depends heavily on Slack's third-party app ecosystem or its Huddles feature, check the GitHub repository to see the current state before committing.
For developer-heavy teams where the primary use case is text communication — which describes a large share of Slack's actual user base — msga covers the daily workflow well.
Choosing the right path
A practical decision framework:
- You need message data stored on your own servers → evaluate Mattermost, Zulip, or Matrix and budget time for the migration.
- You need to reduce per-seat SaaS cost → same path, or explore whether Slack's own tier changes would help first.
- You need a lighter, faster desktop experience without migrating your workspace → try msga. It is free, GPL-licensed, and requires no changes to your Slack configuration.
- You are on Linux and the official Snap or Flatpak build of Slack feels sluggish → msga is a particularly strong fit; native Qt6 integration with the system compositor means better performance and fewer packaging quirks.
These paths are not mutually exclusive. A team can run Mattermost for internal communication while some members use msga as a client for an external-facing Slack workspace. The tools serve different layers of the stack.
The open-source angle
msga being GPL-3.0 matters beyond licensing formality. It means you can audit the code to confirm it is not doing anything unexpected with your Slack credentials or message content. For teams in regulated industries where even the client software needs to be reviewable, that is a concrete benefit the official closed-source app cannot offer.
It also means the project can be forked, patched, or extended by anyone. If a feature is missing and important to your team, contributing upstream or maintaining a fork is a real option — not just a theoretical one.
If the self-hosted Slack alternative you actually need is a lighter, auditable, native client rather than a full server replacement, msga is worth a look. Download it from /#download and compare the resource usage yourself.