This isn't an open source project like Anubis and apparently you have to pay $50 for advanced features:

> POWBlock is shareware. Good shareware we hope, because we only gate the optional "enterprise-level" super-nerd stuff behind a paid license and give 100% of the main features for free. But for that reason the source code is closed and private. That being said, we're not scared of code reviews. If you're a bona fide security researcher willing to sign an NDA and publicly vouch for what you find, we can let you look at it.

> Reach out to us and/or drop some crypto. A license key is a flat 50 US dollars. If you buy as an individual operator, the key is valid for your lifetime for as many copies as you want, any where you want, just as long as you are the sole owner/renter of the physical servers you deploy on. Corporate/government entities need 1 license key for each US State and/or non-US country they plan to deploy it in, but can do unlimited deployments in any such place that they have a license.

Kudos for finding the perfect name

If you're in this space you've heard all about tools like Anubis and Haproxy-protection and the various Lua engines out there, but this is the first PoW program built as a true network stack primitive. It's a composable drop-in microservice designed to work with any server that can speak HTTP and make a hash, and gives it powerful proof-of-work defense capability. In 1 megabyte. In development for over two years, and running on real websites since 2025. It went public a couple weeks ago.

Varnish gurus should especially love it.