Rosterr uses a Roblox Open Cloud API key to read your group's members and ranks. (This is a different key from a Rosterr game API key.)
Create it
Open the Roblox Creator Hub and go to Credentials (Open Cloud API keys).
Choose Create API key.
Give it a name, for example "Rosterr".
Make it a user key, not a group key.
Add the Groups API system, with the permission group:read, and choose your group.
Choose an expiry that suits you. If the key expires, Rosterr stops reading your group until you replace it.
Save and copy the key.
Give it to Rosterr
When creating a workspace: paste it in step 2 and choose Test key.
Later: Settings > Roblox & ranking > Roblox Open Cloud API Key.
If you want Rosterr to rank people in Roblox
The key also needs the group permissions that allow promotions, demotions and rank changes. See "Connect a ranking service for promotions and demotions (Open Cloud or RankGun)". Without them, logbook entries are recorded but ranks do not change in Roblox.
Keep it safe
Treat it like a password. Rosterr stores it encrypted. If it leaks, delete it in the Creator Hub and make a new one.
Troubleshooting
"Test key" fails. Check it is a user key, the Groups permission is group:read, your group is chosen, and it has not expired.
Members do not appear after a sync. The key may not cover your group.
Ranking fails. The key may lack the ranking permissions. Check the Roblox group's own rules too.
Related articles
How do I create a workspace for my Roblox group?
Connect a ranking service for promotions and demotions (Open Cloud or RankGun)
