Markdown for Slack: Formatting Messages Like a Pro

Slack uses what they call "mrkdwn" (yes, without the vowels). It's inspired by Markdown but differs in several key ways. Here's the complete syntax:

Bold

Use single asterisks — not double like standard Markdown:

*This is bold in Slack*

Standard Markdown: **bold**  ← Doesn't work in Slack
Slack's way:       *bold*    ← This is bold

Italic

Use underscores:

_This is italic in Slack_

Strikethrough

Same as standard Markdown — tildes:

~This is strikethrough in Slack~

Note: Slack uses single tildes (~text~), while standard Markdown uses double (~~text~~).

Code formatting is one area where Slack aligns closely with standard Markdown:

Inline Code

Use `npm install` to add the package.

This renders in a monospace font with a subtle background — great for commands, file names, and technical terms.

Code Blocks

```
function hello() {
  console.log("Hello from Slack!");
}
```

Unlike Discord, Slack does not support syntax highlighting in code blocks. Adding a language name after the backticks (like ```javascript) has no effect — the code won't be color-coded. It'll display as plain monospace text.

Quote text using the > character, same as standard Markdown:

> This is a blockquote in Slack.
> It shows with a gray left border.

Slack renders blockquotes with a subtle gray left border. They're great for quoting previous messages, highlighting key points, or calling out important information.

Slack supports basic lists, though the formatting is more limited than standard Markdown:

• Bullet point (type • or use - )
• Another point
• Third point

1. Numbered item
2. Second item
3. Third item

Slack will render dashes (-) and bullets (•) as unordered lists and numbered sequences as ordered lists. Nested lists are supported but can be finicky — use indentation with spaces.

Slack automatically converts URLs into clickable links. But if you want custom link text, use Slack's angle bracket syntax:

Standard Markdown (doesn't work in Slack):
[Click here](https://example.com)

Slack's syntax:
<https://example.com|Click here>

The pipe character (|) separates the URL from the display text. This is one of the most unintuitive differences from standard Markdown — the URL comes first, not the text.

Several standard Markdown features are missing from Slack:

• Headers — No # header syntax. Use bold text to simulate section titles.
• Tables — Not supported. Use code blocks for tabular data.
• Images — Can't embed images with Markdown. Upload them directly or share URLs.
• Horizontal rules — No --- dividers.
• Syntax highlighting — Code blocks are monochrome.
• Spoiler tags — No equivalent of Discord's ||spoiler|| syntax.
• Standard Markdown links — [text](url) doesn't work. Use <url|text>.

Feature        Standard Markdown    Slack mrkdwn
─────────────  ──────────────────   ──────────────
Bold           **text**             *text*
Italic         *text* or _text_     _text_
Strikethrough  ~~text~~             ~text~
Inline code    `code`               `code`
Code block     ```code```            ```code```
Blockquote     > text               > text
Link           [text](url)          <url|text>
Headers        # Header             ✗ not supported
Tables         | col | col |        ✗ not supported

• Use threads liberally. Format the main message cleanly, then add details in the thread. This keeps channels scannable.
• Bold your TL;DR. Start important messages with a bold summary: *TL;DR: We're shipping v2 on Friday.*
• Use code blocks for data. When sharing JSON, logs, config snippets, or tabular data, wrap them in triple backticks for readability.
• Quote when replying. Use > to quote the specific part of a message you're responding to — it adds clarity.
• Use emoji reactions instead of "thanks" messages. A 👍 or ✅ react is cleaner than a standalone message that clutters the channel.
• Break up long messages with blank lines between paragraphs and bold section headers. Walls of text get skipped.

If you're building Slack bots or Workflow Builder automations, you'll use the same mrkdwn syntax in your API payloads. The text field in Slack's chat.postMessage API accepts mrkdwn by default:

{
  "channel": "C1234567890",
  "text": "*Deployment complete* :rocket:\nVersion `v2.1.0` is live.\n> All health checks passing."
}

For richer formatting in bot messages, consider using Slack's Block Kit — a JSON-based layout system that supports sections, dividers, images, buttons, and more. Block Kit gives you formatting capabilities far beyond what mrkdwn alone provides.

If you write content in standard Markdown and need to share it on Slack, you'll need to convert the formatting. The main changes:

1. Replace **bold** with *bold*
2. Keep _italic_ (same in both)
3. Replace ~~strike~~ with ~strike~
4. Replace [text](url) with <url|text>
5. Remove headers — replace with bold text

MarkdownFTW includes a Slack export mode that handles these conversions automatically — write standard Markdown and copy the Slack-formatted version directly.