Everything you need to know about Quassel IRC, the free open-source always-on IRC client with a core-client architecture, before you install it.
Quassel IRC is a free and open-source IRC client introduced in 2008 that solves a long-standing IRC problem: staying connected and not missing messages when you close your laptop or switch devices. It does this through a core-and-client architecture, where a persistent core process maintains your IRC network connections and stores chat history in a PostgreSQL or SQLite database, while separate graphical clients built with the Qt framework connect to that core whenever you want to read or send messages.
Because the core keeps running independently, Quassel behaves similarly to pairing a terminal multiplexer with a text-based IRC client, but with a full graphical interface and native apps for Linux, macOS, and Windows, along with community-maintained mobile clients for Android and iOS. The project is maintained entirely by volunteer contributors under the GPL and has no commercial entity, pricing, or company behind it.
Quassel supports simultaneous connections to multiple IRC networks from a single core, SSL-encrypted connections between the core and any attached clients, and flexible multi-identity management so users can present different nicknames or away messages on different networks. Chat history is retained in the core's database, meaning conversations that happened while no client was connected are still available once you reconnect.
Additional conveniences include command aliases for frequently used IRC commands, proxy support for connecting through restricted networks, and a native, customizable Qt-based interface. The core-client split also means a single core installation can serve multiple client devices, so a user can pick up the same synchronized conversation on a desktop client and a mobile client without losing scrollback or state.
Quassel IRC is entirely free. It is distributed under the GNU General Public License version 2 and version 3, which means the source code is open, redistribution and modification are permitted under the license terms, and there is no cost to download, install, or use the software.
There are no premium tiers, subscriptions, or paid add-ons. Running Quassel does typically require hosting the core process somewhere that stays online, such as a personal server, always-on desktop, or virtual private server, which may carry hosting costs, but those costs are unrelated to the Quassel software itself, which remains free regardless of deployment.
Yes. Quassel IRC is completely free and released under the GNU General Public License versions 2 and 3, with no paid tiers or subscriptions.
Quassel has native clients for Linux, macOS, and Windows, plus community-maintained mobile clients Quasseldroid for Android and iQuassel for iOS.
Quassel splits into a persistent core that maintains IRC connections and stores history, and separate clients that can connect or disconnect from that core at any time without losing chat state.
Yes, community-maintained mobile clients exist: Quasseldroid for Android and iQuassel for iOS, both of which connect to a Quassel core.
Quassel is an active open-source project with a volunteer maintainer team, though its release cadence has slowed, with version 0.14.0 released in January 2022 as the most recent major version.
Quassel is released under the GNU General Public License, dual-licensed as GPL-2.0-only or GPL-3.0-only.
Unlike single-process clients such as HexChat, Quassel separates a persistent core from the client interface, so your IRC connection and history survive even when no client is attached, without needing separate bouncer software.
Yes, Quassel requires running the core component somewhere that stays online, such as a personal server, NAS, or VPS, in addition to installing a client to connect to it.