Hello,
Since September 1st, my Viessmann app has stopped working. When configuring it, the following error message appears:
Does anything need to be changed?
Hi all,
Quick status from me (Pelle, maintainer of the Viessmann ViCare app for Homey Pro).
Status: I havenât had time for this project since December 2024 as Iâve had to focus on other priorities. Thanks for your patience. Thanks for your patience.
Polling: The app polls every 2 minutes to stay within the free API limits.
Thanks: Big thanks to @Sam_Coussens for flagging the upcoming Viessmann API/IAM domain change. Iâll submit an updated version before the old domain stops working. 
If you canât log in / âinvalid redirect URIâ error:
Please double-check your Viessmann developer client setup and Homey app settings:
-
Go to app.developer.viessmann.com â Your clients
-
Ensure you have a client (e.g. Name: Homey)
-
reCAPTCHA: Disabled
-
Redirect URI: https://callback.athom.com/oauth2/callback
-
In Homey â App Settings for the Viessmann app: paste the Viessmann Client ID and save.
After saving, try adding the device again in Homey.
Feature requests / help wanted: Lots of great ideas have come in. If you have time and knowledge to help build new features, please contact me â Iâm happy to help you get started. The source code is on GitHub.
You can DM me here or email pelle@forint.se.
Thanks again for your support, and sorry for the recent silence.
/Pelle
1 Like
Hi Pelle,
Thank you for your information. I had to create a new client in the Developer Portal and reconfigured the app. I was then able to add my heating system as a new device. Everythingâs working again now.
I hope someone can help with further development. It would be great if the individual Viessmann components of the heating system (radiator thermostats, climate sensors) could be integrated into Homey as separate devices.
It would be ideal if you could control the temperature of a radiator thermostat on a Homey dashboard. Maybe that will work someday?
Thank you for your support!
Hey @Pelle_Rosengren
Veissmann has now changed their endpoints, so the application has stopped working. At least for me.
Best regards
Gustaf
Hi @Gustaf_Berg, updated version is available for download (if not automatically updated). Viessmann ViCare | Homey
2 Likes
Thanks. Works again!
1 Like
Hi, Iâm absolutely thrilled with this app 
Thank you 
However, Iâm missing a program for my Vitodens 200-W in the operating mode selection.
On the other hand, the âForced Reducedâ command is missing in operating mode.
Hello, is there an overview of the settings available in âOperation modeâ? I see âdhwAndHeatingâ there. What are the others called?
I followed the steps. I get the callback, but on the âNew Devices Foundâ page i am getting only âUnknown errorâ. The device is a Vitodens gas boiler, added in ViCare.
Any idea what could be wrong?
Hello, is there an overview of the settings available in âOperation modeâ? I see âdhwAndHeatingâ there. What are the others called?
