Regex for Hashtag
Matches a social media hashtag like #OpenAI.
^#[A-Za-z0-9_]+$
Proof it works
| Sample | Should match | Result |
|---|---|---|
#OpenAI |
yes | pass |
#travel_2026 |
yes | pass |
# |
no | pass |
no-hash |
no | pass |
# space |
no | pass |