Why Markdown breaks in Slack
Slack's formatting looks like Markdown but isn't. Slack's own developer docs say its mrkdwn syntax is "inspired by markdown, but uses different rules". In Slack, one asterisk on each side means bold, so the double asterisks in a ChatGPT or Claude answer aren't Slack's bold markup, and Markdown's single-asterisk italic comes out bold. Slack's message markup has no headings either, so the pound signs stay in the message. You don't have to retype any of it.
What the Slack formatter changes
| Format | You paste | Message box | Slack API (mrkdwn) |
|---|---|---|---|
| Bold | **text** | *text* | *text* |
| Italic | *text* | _text_ | _text_ |
| Strikethrough | ~~text~~ | ~text~ | ~text~ |
| Heading | # Title | *Title* | *Title* |
| Link | [text](link) | [text](link) | <link|text> |
| Bulleted list | - item | • item | • item |
| Table | rows of pipes | aligned columns in a code block | aligned columns in a code block |
| Code and quotes | backticks and > | unchanged | unchanged |
| Special characters | & < > | unchanged | & < > |
Message box or Slack API: which one you need
Pick Slack message box if you're pasting into Slack yourself. Pick Slack API (mrkdwn) if a bot or a script posts the text for you. Not sure? Choose the message box.
Turn on markup in Slack once
Slack's message box has a formatting toolbar by default. To type formatting codes like *bold* instead, turn on its markup setting:
- On desktop, click your profile picture in the sidebar.
- Select Preferences, then select Advanced.
- Under Input Options, check Format messages with markup.
With it on, Slack formats the message when you send it, not while you type, so the box shows the asterisks until you hit Enter. That's normal.
How to make a table in Slack
Slack's message markup has no table syntax, and neither does mrkdwn text. What works is a code block (text between three backticks). The formatter puts your table in one and adds spaces so the columns line up. Inside a cell, bold is dropped and a link keeps only its text.
Markdown
In Slack
How this Slack formatter works
It runs in your browser, and nothing you paste is uploaded.
Images become their plain link, without the description. Footnotes and HTML tags stay as plain text. When one format sits inside another, like a link inside bold text, Slack decides how it looks.
FAQ
How do I start a new line in Slack without sending the message?
Press Shift and Enter together. If you'd rather have Enter start a new line, Slack lets you change that in your preferences.
How do I make a list in Slack?
In the message box, type an asterisk and a space to start a bulleted list, or "1." and a space to start a numbered one. With "Format messages with markup" turned on, Slack doesn't format lists for you, so type the • yourself or paste the list into the formatter above.
Want a custom emoji for the same channel? The free Slack emoji maker turns an image or a short word into one, sized for Slack and Microsoft Teams.
Have Dash post the update for you
If you're pasting the same weekly update into Slack every Friday, hand it to Dash, our AI teammate in Slack and Microsoft Teams. Dash pulls the numbers from your tools into reports like the cash update above, posts them where you choose, already formatted, and asks a person before it changes anything.