slak 26.6.1

A terminal Slack client built on Textual

slak

A terminal Slack client built on Textual.

Unofficial. Uses Slack's internal browser protocol and may violate Slack's TOS. Not affiliated with Slack Technologies, LLC.

Features

Keyboard-first. Borderless Textual UI — workspace rail, channel sidebar, message pane, compose. The compose box is focused on launch, so you just start typing. Tab cycles focus, Ctrl+P opens the command palette (every action), and F1 shows the full keybinding reference.

Workspaces & navigation

• Multiple workspaces with concurrent live connections; Alt+1…Alt+9 jump, Ctrl+W opens a filterable switcher.
• Ctrl+K fuzzy channel/DM finder — also lists public channels you haven't joined (marked · join) and joins one on selection; Alt+←/Alt+→ walk channel history; Ctrl+B toggles the sidebar, Ctrl+T the thread panel.
• Drag the dividers between the channel list / messages / thread to resize them; the widths are remembered across restarts.
• Cache-first startup: your last context renders instantly while sync runs behind it.

Messaging

• Send, edit (Ctrl+E), and delete messages; reactions (Ctrl+R); threads with a follow-the-cursor reply panel.
• Ctrl+N new-message composer (DM and group DM); @/: mention & emoji autocomplete; Ctrl+O opens link(s) in a message; Space previews image attachments.
• In-channel (Ctrl+F) and workspace-wide (Ctrl+Shift+F) search.
• Typing indicators, both directions.

Sidebar

• Slack-native sections (users.channelSections.list, linked-list order) with a pinned ★ Starred section, or config-glob sections ([sections.<name>]) as a fallback — grouped, collapsible, live-updated on section/star events.
• A ⚑ Threads row opens the threads view (your subscribed threads, newest-reply first). DM and group-DM names are resolved to member display names.

Rendering

• Slack markdown, mentions, custom emoji (inline images on kitty), fenced code blocks (rendered literally on a tinted block), and Block Kit / legacy attachments (headers, sections, fields, context, dividers, controls).
• Inline images for files and attachments — kitty graphics on kitty, ▀ half-blocks on any truecolor terminal.
• Space previews the selected message's image full-screen. Default is an in-terminal preview (works over SSH); set [appearance] image_preview = gui to open it in an external viewer on the local machine instead.
• Colour themes (13 built-in incl. a true-black oled and terminal-following ansi-dark/ansi-light, plus ~/.config/slak/themes/*.toml and [theme] overrides), switched live with Ctrl+Y; the sidebar is auto-kept contrasting (CIELAB).
• Optional user avatars beside messages ([appearance] avatars = on, off by default) — rendered as 4×2 half-blocks in a left gutter.
• Optional coloured author names ([appearance] colored_names = true, off by default) — each author name and @mention tinted by a deterministic hash of the user id.
• Local nicknames — Ctrl+G on a message renames its author just for you (stored by user id in [nicknames]); the nickname shows everywhere that name does.
• Optional author grouping ([appearance] group_within_minutes = N, 0 = off) — consecutive messages from the same author within N minutes drop the repeated name/timestamp header (and avatar), so a back-and-forth reads as a block.
• Private channels show a padlock — the single-width `` glyph when an installed font covers it (Nerd Font / FontAwesome, detected via fontconfig), else a narrow ⚿ fallback (`[appearance] nerd_font = auto|on|off`).

Realtime & integration

• RTM with exponential-backoff reconnection and missed-history backfill.
• Desktop notifications, presence/DND, terminal tab-title unread indicator.
• Opt-in embedded MCP server ([mcp] enabled = true) — an AI client reads your context (slak_get_context) and drafts a reply (slak_set_draft, draft-only). Run the adapter with slak --mcp (pip install 'slak[mcp]').

Underneath: a pluggable SlackClient (browser-cookie auth, with an in-memory fake for offline/dev), a self-healing SQLite cache (WAL + FTS5), and round-trippable TOML config. ~340 tests.

Not yet wired: the sixel image protocol (half-blocks cover non-kitty terminals).

Install

Recommended — pipx installs it isolated and puts slak on your PATH globally:

pipx install slak
pipx install 'slak[mcp]'   # with the optional MCP adapter

Or with pip (ideally in a virtualenv):

pip install slak

Debian / Ubuntu (.deb)

Requires Ubuntu 24.04 (Noble) or newer — slak needs Python ≥ 3.12, which 24.04 is the first Ubuntu LTS to ship (22.04 has 3.10 and is not supported).

A pre-built .deb is attached to each release; it bundles slak + all deps in a private venv under /usr/lib/slak and depends only on python3.12 (apt pulls it automatically):

sudo apt install ./slak_<version>_noble_amd64.deb
slak

To build one yourself (run on the same release you install on — the bundle is tied to that release's Python minor version and CPU architecture):

packaging/build-deb.sh                  # -> dist/slak_<version>_<arch>.deb
sudo apt install ./dist/slak_*.deb

Remove with sudo apt remove slak.

Nix

A flake is provided:

nix run github:Frodotus/slak     # run without installing
nix profile install github:Frodotus/slak
nix develop                       # dev shell with deps + pytest

Either way you get a slak command.

First run

Just run it:

slak

On the first launch (no workspace configured yet) slak opens a short setup wizard that walks you through copying your Slack browser session — an xoxc-… token and the d cookie — from https://app.slack.com via DevTools. Credentials are stored locally and sent only to Slack. After that, slak connects to your workspace automatically.

slak                  # your workspace (runs the setup wizard on first launch)
slak --add-workspace  # run the wizard again to add another workspace
slak --list-workspaces
slak --demo           # explore a seeded demo workspace (no account needed)

(slak with no workspace in a non-interactive shell — CI/cron — prints setup instructions and exits rather than prompting; use --demo there.)

Develop

python3 -m venv .venv && . .venv/bin/activate
pip install -e ".[dev]"

python -m slak --demo               # run against a seeded demo workspace
textual run --dev slak/dev.py       # run with live CSS hot-reload
textual console                      # (separate terminal) stream logs
pytest                               # run the test suite

The look is themeable CSS — edit slak/ui/styles/app.tcss while running under --dev to restyle instantly.

Versioning

Releases use calendar versioning YY.M.N — two-digit year, month (not zero-padded), and the Nth release that month. For example the third release in June 2026 is 26.6.3. scripts/bump_version.py derives the next version from the date and existing tags and writes it to pyproject.toml and slak/version.py.

License

GNU General Public License v3.0 or later.