I’m currently working on a service that includes an API, website, and iOS client and have been using an app called Workspaces to efficiently switch between each of those projects.
Workspaces allows you to associate a number of resources (files & folders, websites, emails, etc.) with a project. You can specify which resources are opened automatically when you start working on a project, and the rest are quickly available via the menubar.
For example, starting my API project opens Terminal (at the project’s directory), my Xcode project, and a Paw document for testing the API. I can visit the repo’s Project page (or any of the other resources) from the menubar whenever I need to.
I’ve been very impressed by the app so far and look forward to seeing what the developer adds in future versions.