Proton AG

Proton AG is the developer behind two entries in the TopDown APK catalog, both VPN apps. The Android edition of Proton VPN has over 100 million installs and a 4.7 rating on Google Play. The Windows edition is listed separately under the same name.

Both apps are released under open source licenses. The Android version uses GPL-3.0-only, while the Windows entry is listed as GPL-3.0. The Android listing was updated on October 27, 2026, and the Windows listing on October 19, 2026. The developer's website is protonvpn.com.