Cascade Chat – A Hackable IRCv3 Client for macOS, Windows, and Linux

Hello HN! I'm Matt and today I'd like to show you Cascade Chat.

One of my earliest internet experiences was with mIRC. I always admired its straightforward, pleasant UI and the way it wove a hackable core into the code. The way you could build on the visual and API layers of the underlying IRC client to me was fascinating software machinery. It was truly a client that you could build on top of.

As my career has progressed, I moved away from Windows and adopted Linux as my daily driver. That was where I found HexChat, the closest thing I could find to mIRC many years later. While I really enjoyed HexChat, it wasn't quite what mIRC offered. I eventually found myself on macOS with no clear analogue to either. That's why I built Cascade Chat.

Cascade is a modern IRCv3 client. It supports persistent local history with full-text search, network management, replies, typing indicators, link previews, pinned messages, native notifications, SASL authentication, server-time, chathistory, account and away tracking, and the ratified IRCv3 capability set.

I also wanted Cascade to be hackable, so I built in two fundamentally different layers:

- Scripting powered by Go scripts for personal automation, event handlers, and timers. Scripts run in-process with no access to the standard library, filesystem, or network. - Plugins that communicate over JSON-RPC and can be written in any language as external processes.

Stack-wise, it's a Go application built on top of Wails v3, which leverages the OS's native WebView to render modern web tech frontends as desktop applications. The result is an Electron-like experience without packaging a separate Chromium runtime.

Full disclosure, since this is HN: I built Cascade using agentic engineering. I made the product and UX decisions, designed the architecture and code interfaces, and I reviewed and dogfooded the resulting work. Coding agents implemented much of the space between those decisions.

To further ensure consistent quality, I built gates around that process rather than treating generated code as finished. I focused on unit and integration tests, full-stack end-to-end tests against a real IRCv3 server (Ergo), automated release candidates, and regular dogfooding of the prerelease channel.

Cascade is open source under the BSD 3-Clause license. Prebuilt packages are available for macOS, Windows, and Linux. The current builds are unsigned, so macOS and Windows require a first-run confirmation step that I've documented in the README.

I'd love to know if you'd make Cascade your daily IRC client, and if not, what that'd take! Feedback and PRs welcome.