Markdown bold
Wrap text in two asterisks to make it bold. Two underscores do the same thing, and both are equally correct, though asterisks are the safer habit.
**bold text**
__also bold__bold text
also bold
***bold and italic***
**bold with _italic_ inside**bold and italic
bold with italic inside
What usually goes wrong
- No spaces inside the markers.
** bold **renders as literal asterisks, because a marker followed by a space is not treated as an opener. - Underscores do not work inside a word.
snake__case__herestays as it is, on purpose, so that code-like words survive. Asterisks do work there. - Bold in a heading is redundant on nearly every platform: headings are already bold.
Where it behaves differently
| Platform | Behaviour |
|---|---|
| GitHub, Obsidian, Notion | Both ** and __ work everywhere. |
| Discord | Both work. ***text*** gives bold italic. |
| Slack | Slack is different: bold is a single asterisk, *bold*. |
Questions
Asterisks or underscores for bold?
Asterisks. They behave the same in every renderer and they work inside words, where underscores deliberately do not.