slackfxa small chat client and command line, from fxslack

A chat client for Windows that is one process instead of seven, with a command line in the same program that reads your workspace for you and asks a person before it changes anything. Both act as you, through an app you create in your own workspace.

Download for Windows Source and documentation
slackfx showing the release channel of an invented workspace: a message with reactions and a thread, a code line, a build attachment, a file and a mention
The window, on an invented workspace. slackfx --demo opens the same one without a login.

What it does

A client that stays small

slackfx lives in the tray. Open its window when you want to read or write, close it and the memory goes back. Measured in October 2026: about 200 MB with the window open, about 40 MB a couple of minutes after it was closed, where the official app held about a gigabyte.

Messages as they arrive

New messages show within a second over a live socket connection, with a notification for a direct message, a group chat or an @-mention. Channels, group chats and direct messages are in one list with a filter, and unread ones are marked.

A command line for scripts and agents

slackfx followed by a verb reads channels, threads and search results, and exports a whole channel with its files. It is made to be driven by AI coding agents, so the output is plain and every verb has --help.

Writes need a person

Every change goes through the running client: slackfx send, edit, delete, react, mark, scheduling, and anything sent with raw. A window shows exactly what is about to happen and waits for F2. If the client is not running, the change is refused. Reads are free.

Set it up

  1. At api.slack.com/apps create an app from a manifest, using the manifest in the repository. It asks for user-token scopes only.
  2. Install the app to your workspace and copy its User OAuth Token (xoxp-). Generate an app-level token with connections:write (xapp-) for live messages.
  3. Save them in %USERPROFILE%\fxslack\slackfx\app-config.json: 
    { "user_token": "xoxp-...", "app_token": "xapp-..." }
  4. Run slackfx auth --app, then slackfx whoami, then start slackfx with no arguments for the tray and the window.

Install

Download slackfx.exe from the latest release and run it. It needs Java 25 or later. The exe fetches its program file from the same release and checks it against a checksum built into it, and is both the client and the command line. The client checks for a newer release when it starts and every 24 hours, and asks before it updates; slackfx update does it from a terminal.