Yes! Blokada is an open source project.
There are three modes o operation in Blokada: Libre, Cloud, and Plus.
Libre mode is available on Blokada for Android, and it is free, local on-device fake VPN based adblocking.
Blokada Cloud is our newest, cloud-based adblocking, which is much more reliable and faster. It is currently the only reliable solution for iOS (more here). As maintaining cloud costs money, we ask for a low price subscription for it.
Blokada Plus is an optional, premium feature that is paid. You can still use Blokada without ever enabling Blokada Plus.