Collaboration

Although most esolangs are created by a single author, sometimes, multiple authors can work on a single esolang. There are many ways people can collaborate.

User edited pages

This is the most common type of collaboration. Someone makes a page on Esolang Wiki, and then declares that 'anyone can edit it', usually with some rules that an editor may follow. Some examples include BFInfinity, UserEdited, Usernames, and User talk:User:Main page/w/wiki/User:NotPrySigneToFry/what.

E-mails

Some people that already know each other might use e-mail to communicate to each other regarding the matter of esolang creation. One example of this is robots.txt.

Git

This is mostly applicable to esolang implementations, they can be developed collaboratively using git, usually hosted on git forges.