join the project
join in the project
join the project is more natural.
@Acer "Join the project" suggests taking a role in a group (e.g. becoming a core contributor) while "Join in the project" suggests merely taking part in a project's activities (e.g. sending a patch).
Most people will use a more specific phrase for the second case (e.g. "participate in", "contribute to", "help out with").
Oh. I made a mistake! I said that I ll join the project in the workplace.
Thanks for letting me know.
@Acer If you're helping with a project at work, I'd consider that taking up a role. Even if you aren't, the meanings are similar enough that nobody would have noticed.
Sorry about the confusion.
