The General Data Protection Regulation (GDPR) requires developers to provide a way for people to request that their data be deleted

Badges doesn't record any user information on its servers in clear. The data used by the application and by the server are end-to-end encrypted from device to device with cryptographic keys stored encrypted whithin the phone or within the application sandbox of your icloud instance

By erasing the application on all your iOS and macOS devices, your cryptographic keys are erased and the 128bits encrypted data remaining in your devices and in the servers can never be recovered. The unrecoverable encrypted data stored on the servers are purged after several weeks