Zero is Open Source Software

Specifically, the Zero client and server are Apache-2 licensed. You can use, modify, host, and distribute them freely:

https://github.com/rocicorp/mono/blob/main/LICENSE

Business Model

We plan to commercialize Zero in the future by offering a hosted zero-cache service for people who do not want to run it themselves. We expect to charge prices for this rougly comparable to today's database hosting services. We'll also offer white-glove service to help enterprises run zero-cache within their own infrastructure.

These plans may change as we develop Zero further. For example, we may also build closed-source companion software – similar to how Docker, Inc. charges for team access to Docker Desktop.

But we have no plans to ever change the licensing of the core product: We're building a general-purpose sync engine for the entire web, and we can only do that if the core remains completely open.