Does Slack support Markdown tables?

I want to send a Markdown table to Slack with its postMessage API, but I got raw content in Slack instead of a rendered table. Does Slack support Markdown tables? Ir is there any other way to present tabular data in Slack? I know Slack doesn't support HTML.

I tried chat.postMessage and files.upload, also formatting text with fixed column length but it looks kind of ugly, so I am figuring out a way to make it look better.

Here is my HTTP request code, content-type is JSON:

url :
body :
{ "channel": "RKAID4I", "text": " | Tables | Are | Cool |
|---------- |:-------------: |------: |
| col 1 is | left-aligned | $1600 |
| col 2 is | centered | $12 |
| col 3 is | right-aligned | $1 |"
}

I was expect table like format, but the actual output is exactly as what I sent. Is it because my Markdown message is wrong or Slack simply doesn't support Markdown tables?

2 Answers

No, in fact, Slack doesn't support Markdown in messages¹ at all. It uses its own similar-at-a-glance format called mrkdwn which has some notable differences with Markdown:

• In Markdown, both * and _ are used for emphasis
• In Markdown, both ** and __ are used for bold
• In mrkdwn * is used for bold and _ is used for emphasis
• Markdown has no syntax for strikethrough (though some implementations have added it, e.g. in GFM which uses ~~) but mrkdwn uses ~ for strikethrough
• Link syntax is very different
• mrkdwn doesn't support headings
• Probably more

Don't expect arbitrary Markdown² to work in Slack messages.

¹Slack does support Markdown in posts which can be created using the files.upload API endpoint setting filetype to post.

²Note that tables aren't supported in regular Markdown either. Like strikethrough, some implementations have added these.

Slack does not support rendering of tables so this markup will not work.

You have two alternatives:

• You can use fields, which will be rendered as 2 columns on most devices. See fields in layout blocks.
• You can convert your table into an image (outside Slack) and
  attach the image to your message.