Here’s the direct link to the SmartThings github public repository. This includes many previously published but now deprecated smart apps, such as the big switch, just in case anyone is looking For them.
And here’s the FAQ on using Custom code:
So you’re new to SmartThings, you asked a question, and someone suggested “custom code” as an answer.
Or you were browsing the forums, and you found something that sounded like it would be perfect for what you wanted, but again, “uses custom code.”
What does that mean, how hard is it to do, and what’s the difference between a “SmartApp” and a “Device Type Handler”?
(Note: the official terminology has changed a couple of times. “device type handler,” “device handler,” “DTH,” and “device type” all mean the same thing, and you will find all these terms used in the forums.)
SECTION I: SMARTAPPS AND DEVICE HANDLERS: WHAT THEY ARE
SmartAPPS: Tiny Programs to decide what a specific device should do when, or to collect the information from a specific device
SmartApps, including the various f…
And the official announcement on the SmartThings github repo:
At SmartThings, we understand that not one single person or company can possibly create every solution or scenario. Therefore, since the beginning, we knew we wanted to make our platform open; open for anyone to create solutions and integrate with SmartThings.
As an open platform, we recognize that giving our community developers access to the repository housing our SmartApps and Device Handlers is extremely important. We are pleased to announce that the SmartThings GitHub repository is now public, allowing you to browse the source code in a more familiar environment for developers to build in. Now, with the power of GitHub and SmartThings developers, features like pull requests and version control will enable you to collaborate and build robust and elegant solutions to tailor ho…
If a smartapp has an individual thread in the community-created smartapp section of the forum, it’s best to look there as the author may have additional comments and you can also ask questions.
But if there is no individual thread or you just want to poke around and see everything, you can start from the github link at the top of this post, or use the same link which is in the IDE.