Tip4Commit.com doesn't require user registration. Anybody can choose any open source GitHub project and donate any amount of bitcoins to it.
Each donation pays for tips during 30 days. Each commit accepted by project maintainer will be tipped.
We use the following method to calculate the size of the tip:
- <should be spent by time> = <time elapsed since donation> * <donation amount> / <30 days>
- <tip amount> = <should be spent by commit time> - <has been spent by commit time>
If we don't know recipient's Bitcoin address, we send him/her an email with a unique link that allows to specify it. Alternatively developers can sign in via GitHub, but it is not required.