How to use Markdown in Slack — and why it's weird (mrkdwn)
Slack supports markdown-style formatting but with its own dialect called mrkdwn: single-asterisk bold, no headings, and a hidden setting you should know about.
How to use Markdown in Slack (and why it's weird)
Slack does markdown. Sort of. Slack actually speaks its own dialect (literally called mrkdwn in their docs, vowels sold separately) and knowing where it differs will save you some mangled messages.
The syntax
| You type | You get |
|---|---|
*bold* | bold (single asterisks!) |
_italic_ | italic |
~strikethrough~ | |
`inline code` | inline code |
``` | code block (no syntax highlighting) |
> quote | block quote |
- item or 1. item | lists |
First: check your settings
Slack has a setting that changes everything: Preferences → Advanced → "Format messages with markup". Switched on, your typed characters format on send, markdown-style. Switched off (the default for many), Slack gives you a WYSIWYG toolbar and intercepts some markdown as you type. If you live in markdown, turn it on and Slack becomes much less annoying.
The dialect traps
- Single-asterisk bold – same trap as WhatsApp. Paste standard
**bold**into Slack and you get stray asterisks. - No headings.
# Big pointjust prints the hash. Convention: a bold line instead. - No markdown links.
[text](url)doesn't work in chat; paste URLs bare, or use the WYSIWYG link button. (Bots and apps can send<url|text>– angle brackets, because why not.) - Code blocks don't highlight. Fine for snippets, sad for anything long.
Copying in and out
Pasting rendered rich text into Slack mostly converts okay. Pasting raw markdown gets you the bold trap and literal # characters. The fix, as ever, is asking an AI to convert ("make this Slack-friendly"), or keeping your canonical text in real markdown and translating at the edge.
That last bit is the actual lesson here: keep the source of truth in plain, standard markdown you own, and treat each app's dialect as an output format. Your docs shouldn't live in Slack anyway; Slack is where things go to scroll away. A markdown knowledge base is where they should live.
More apps and their accents: markdown everywhere 🌍
