How to use hashtags on Mastodon, Bluesky and X (Twitter)
See how hashtags work on Mastodon, Bluesky and X (Twitter), choose one or two readable tags, adapt them per network and check that each tag lists your post.
A hashtag groups your post with others on the same topic, so people who search, open or follow the tag can find your post. To add one, type # and the words without spaces, such as #BirdCount. Pick one or two tags people already use, capitalize each word, and give each network its own set. On Mastodon, only public posts are listed under a tag.
This guide takes one example post from six tags to a short, checked set per network. It doesn’t cover Instagram, TikTok or tools that suggest trending tags.
What a hashtag does on each network
| Network | What the tag does | Who finds the post |
|---|---|---|
| X (Twitter) | Helps the post show in search; the most popular tags often trend | Anyone searching, if your account is public |
| Mastodon | Makes the post findable in search; people can follow a tag | People searching or following the tag, if the post is public |
| Bluesky | Is marked in the post, like links and mentions | Signed-in people who open or search the tag |
X (Twitter)’s hashtag help page says a tag can go anywhere in a post. Mastodon’s posting guide says public posts with a tag you follow show in your Home feed; to follow one, open it and choose “Follow hashtag”. On Bluesky, the app you post from marks each tag in the post’s rich text data.
Write tags people can read
Riverbend Birders, a made-up club in the made-up town of Riverbend, announces its spring bird count. The first draft ends with six lowercase tags: #birdcount #riverbend #birds #nature #spring #weekend.
Fix how each tag is written:
- Capitalize each word: #BirdCount, not #birdcount. Readers and screen readers can then tell the words apart.
- Leave out spaces and punctuation. X (Twitter) says a tag with them won’t work properly, and Mastodon allows only letters, numbers and underscores.
- Don’t use numbers alone. Mastodon doesn’t treat #2026 as a tag.
- Use the tag your readers use in their language rather than translating yours. The multilingual posting guide covers a version for each language.
Choose one or two tags with a purpose
Open a tag before you use it: it may already mean something else. Mastodon’s compose box suggests tags as you type, with how often each is used.
Give each tag a job: one topic tag for the subject, one community tag for people near you. X (Twitter) recommends no more than two tags per post. Cut any tag a reader wouldn’t look for.
The club keeps #BirdCount as its topic tag. #riverbend could be about anything in town, but local birders on Mastodon use #RiverbendBirds, so the club uses that. #birds and #nature are too broad, and #spring and #weekend say when, not what.
Place tags where they help
A tag can sit inside the sentence when it reads as a word: “Join our #BirdCount on Saturday.” Put extra tags at the end in a short row: a long one is hard to follow with a screen reader.
Tags cost characters: #BirdCount uses 10 of the 280 in a standard X (Twitter) post and 10 of the 300 on Bluesky. The character limits guide shows how each network counts.
On Mastodon, only posts set to “Public” are listed under a tag, so don’t choose “Quiet public” or “Followers” for a post you want found.
Adapt tags when you cross-post
A tag people follow on one network may be empty on another, so open each tag on each network. The club finds #RiverbendBirds only on Mastodon. Its final plan:
| Network | Tags | Where they go |
|---|---|---|
| Mastodon | #BirdCount #RiverbendBirds | #BirdCount in the sentence, #RiverbendBirds at the end |
| Bluesky | #BirdCount | In the sentence |
| X (Twitter) | #BirdCount | In the sentence |
| Telegram channel | None | Subscribers already follow the channel |
The cross-posting guide covers mentions, links, media and visibility. In Studio, you write the main text once and add “Custom text” for a network, which that network gets instead. Here the main text carries the Mastodon tags; the other three get custom text.
Check that the tags work after publishing
Open each published post. A working tag shows as a link; if one doesn’t, look for a space, punctuation or numbers alone. On Bluesky, the app you posted from must also mark it. Then open the tag and find your post. On Mastodon, your.server/tags/BirdCount lists posts with the tag; if yours is missing, check that it’s public. On X (Twitter) and Bluesky, search for it; Bluesky shows results once you’re signed in.
For a typo or a wrong tag, the correction guide helps you choose between editing and reposting.
Before your next post, check:
- No more than two tags per network, each with a job.
- A capital for each word, no spaces or punctuation.
- Public visibility where you want the post found.
- Every tag shows as a link, and its page lists your post.
Studio’s counter measures each post against the strictest network you’ve selected, so you see what each tag costs as you write. Studio isn’t available yet, but you can join the waitlist.
