I’m trying to set up homebridge with the smartthigns plugin. I have the smartapp installed using the old IDE. The instructions say to use the SmartThings Classic app but that is no longer available in the Apple app store… Is there any way to get the App URL, App ID, and App Token without the classic app?
help! 
In the Automations section, click on the + in the upper right of the screen, select Add Routine, then tap on the Discover tab near the top, scroll down to find custom smartapps such as homebridge to set up
Do you still need to enable developer mode first?
Not sure anymore. The OP will let us know if it does not show up
Just be aware that smartthings is in the middle of a major architecture change, and the Samsung-hosted free groovy cloud will be going away soon, along with everything that runs there, which includes the groovy smartapp that makes the current homebridge integration work.
So far I haven’t heard of anybody who’s going to write a replacement. A few people are planning to do smartthings to home assistant and then home assistant to homebridge, but that’s a lot of work.
And it doesn’t sound like matter is going to help much in this specific situation because when smartthings announced their plan for matter it’s one way: they’ll be able to bring mattercompliant devices into the smart things app, but they are not intending to have a smartthings hub act as a matter bridge, so smartthings-connected devices won’t show up in HomeKit that way. 
So just something to be aware of before you spend a lot of time and effort on it.
See the following discussion thread. (The topic title is a clickable link)
And in case you missed it, here’s the official announcement on the planned architecture change:
Yeah I know. Hopefully, someone will come up with a solution. Wouldn’t it be nice if if Samsung added Homekit support to smartthings…
Anyway, I got it all installed and working. Thanks to everyone for their help!
I see this marked as solved, but I have the same question as the OP and I do not see this listed when I follow the instructions. Under SmartApps I see “Severe Weather Alert”, “Enhanced Auto Lock Door”, “Ready for Rain”, “Smart Lighting”, “Color Coordinator”, “Keep me Cozy”, “Thermostat Mode Director”, “Smart Windows”, “Speaker Companion”, “Door Knocker”, and “SmartSense by Idah Farm Bureau”.
Nothing like described in “scroll down to find custom smartapps such as homebridge to set up”
There is really no use in installing this version of homebridge integration as all groovy code and IDE will cease by the end of this year.
Instead, you may want to check out installing the following plugin in homebridge. It requires you to set up a Personal Access Token.
Or look at other options such as Home Assistant: