You copy a well-structured ChatGPT response, paste it into Slack, and the formatting is a mess. Double asterisks appear instead of bold text. Hash marks litter the message. Tables are unreadable.
The reason? Slack doesn't use markdown. It uses something called mrkdwn, and the two formats are frustratingly different.
Markdown vs mrkdwn: the key differences
Standard markdown (used by ChatGPT, Claude, Gemini, and most AI tools):
- Bold:
**text**(double asterisks) - Italic:
*text*(single asterisks) - Strikethrough:
~~text~~(double tildes) - Links:
[text](url) - Headings:
# text
Slack's mrkdwn:
- Bold:
*text*(single asterisks) - Italic:
_text_(underscores) - Strikethrough:
~text~(single tilde) - Links:
<url|text> - Headings: not supported at all
When you paste markdown into Slack, the double asterisks for bold don't render (Slack expects single asterisks). The [text](url) link format is ignored. And headings? Slack simply doesn't have them.
What breaks specifically
Bold text
ChatGPT writes **important**. Slack expects *important*. Result: you see literal double asterisks.
Headings
ChatGPT writes ## Section Title. Slack has no heading concept. Result: you see ## Section Title as plain text.
Tables
ChatGPT writes pipe-separated tables. Slack has no table support. Result: a jumble of pipe characters and dashes.
Links
ChatGPT writes [Click here](https://example.com). Slack expects <https://example.com|Click here>. Result: the link syntax is displayed literally.
The fix: convert to mrkdwn first
Unmarkdown™ translates standard markdown to Slack's mrkdwn format before you paste:
- Copy the ChatGPT response
- Paste into unmarkdown.com/for-slack
- Click "Slack" in the destination bar
- Paste into Slack
The conversion handles all the syntax differences:
| Element | Markdown | Slack mrkdwn |
|---|---|---|
| Bold | **text** | *text* |
| Italic | *text* | _text_ |
| Strikethrough | ~~text~~ | ~text~ |
| Code (inline) | `code` | `code` |
| Code blocks | Triple backticks | Triple backticks |
| Links | [text](url) | <url|text> |
| Headings | # text | *text* (bold fallback) |
| Blockquotes | > text | > text |
What about tables in Slack?
Slack simply cannot render tables. No formatting trick or syntax conversion changes this. When Unmarkdown™ encounters a markdown table, it formats the data as clean, readable plain text that makes sense in a Slack message.
It's not as pretty as a table, but it's readable. This is the best anyone can do within Slack's limitations.
What about code blocks?
Code blocks are one of the few things that work similarly in both markdown and mrkdwn. Both use triple backticks. Slack renders them with a gray background and monospace font.
One difference: Slack ignores language labels after the opening backticks. So while ChatGPT writes ```python, Slack just shows a generic code block. No syntax highlighting.
Tips for better Slack messages from AI output
- Keep it concise. Long AI responses overwhelm Slack channels. Consider summarizing before pasting.
- Break up long responses. Send key sections as separate messages with bold headers.
- Use threads. Paste detailed AI output in a thread reply, not the main channel.
- Skip the tables. If the AI response has comparison tables, consider reformatting as bullet lists for Slack.
Other destinations
If Slack's limitations are too restrictive for your content:
- Google Docs supports headings, tables, and full rich text
- Word gets native heading styles and proper table formatting
- Email supports tables, blockquotes, and full formatting
- OneNote handles all 6 heading levels and styled tables
Related reading
- Markdown vs Slack mrkdwn: What's the Difference?
- Obsidian to Slack: How to Share Notes in Slack Channels
- The AI Formatting Problem Nobody Talks About (And How to Fix It)
- 5 Things That Break When You Paste AI Output (And How to Fix Each One)
- From Meeting Transcript to Polished Summary: A Complete Workflow
