What is a Device Handler / Device Type Handler / DTH

[JDRoberts]

The custom code FAQ will give you the quick overview ( this is a clickable link)

[OBSOLETE] FAQ: An Overview of Using Custom Code in SmartThings (SmartThings Classic, Groovy Code)

The original FAQ information in this thread refers to the original smartthings architecture, which was in place through the end of 2022 and a little beyond. Custom code was written in the groovy programming language and ran in the smartthings cloud. As of May 2023, you can no longer add new Groovy DTH‘s or smartapps to your smartthings account. So if you came here because of a link in an old forum thread, or on another site, I’m afraid the Groovy information is no longer usable. All of this was replaced by a new architecture. Cloud to cloud integrations use the smartthings API. Hub connected devices, mostly Zigbee and zwave, now use “Edge Drivers,” written in the LUA programming language. Here’s the official announcement on those: The process for using a custom Edge Driver in the new …

After that you’ll find all the details in the developer documentation. Click on “community” at the top of this page and it will take you to the first page of the forum. Then click on “developer documentation” in the upper right.