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 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.
For the .md file that arrives in Mail
A markdown file on a phone is the worst case: no editor, no preview, and a share sheet full of apps that want to import it into a library. The iPhone and iPad app opens it where it landed, renders it, and lets you edit and save it back.
Soon on theApp StoreDigital Sandbox, who are building it →
For iPhone and iPad.