Hashtags and channels recommendations to Build in Public?

Not a hashtag, but there's a community https://getmakerlog.com/ . You can log your progress and keep your followers informed that you are "actively working on" the project.

Not an existing site but in Jan I am starting to write about my various side projects on builtinpublic.co.uk (yes built rather then build, the tense never sat well with me as would talk about what has happened, not what is going to hopefully happen). Plus the domain was cheaper this way round!

If none of the other sites mentioned take your fancy you are welcome to join me (it's free if happy to post on the main blog).

Thank you for all the comments here. I marked buildinpublic and getmakerlog.

I heard https://mmntm.build/ for a while ago but I think they're still building it.

I found myself posting valuable content and providing people with knowledge without only promoting myself on Twitter is a good source of traffic.

You should fill out your Twitter profile with links to projects you build and try your best to provide value to the community and not only focus on yourself.

I do tweet with #buildinpublic, #startup #indiehackers hashtags, and other matched to the content I'm writing.

Also check out https://buildinpublic.com/

I'd suggest to be active on Linkedin and facebook groups of entrepreneurs.

You can also join some sub-reddits, build an audience on Product Hunt and Makerlog.