A complete beginner's guide to how Celestia works, its key benefits, and how anyone in the world can create their own blockchain in minutes.

Let’s walk through the basics, step-by-step.

Celestia is a modular data availability (DA) network that securely scales with the number of users, making it easy for anyone to launch their own blockchain.

Rollups and L2s use Celestia as a network for publishing and making transaction data available for anyone to download. For them, Celestia provides high-throughput DA that can be verified easily with a light node.

And by making the blockchain stack modular, anyone can launch their own blockchain without needing a validator set.

Data availability answers the question, has the data for this blockchain been published? It is critical to the security of any blockchain because it ensures that anyone can inspect the ledger of transactions and verify it.

Users of a monolithic blockchain usually download all the data to check that it is available.

As blocks get bigger, it becomes impractical for normal users to download all the data meaning that they can’t verify the chain. Modular chains solve this problem by making it possible for users to verify very large blocks using a technology called data availability sampling.

Data availability sampling (DAS) is the new primitive that enables Celestia light nodes to verify DA efficiently. Instead of downloading all data, light nodes only download a tiny portion of each block.

Importantly, DAS allows Celestia to scale with the number of users (light nodes). So, as the light node network grows over time, Celestia can scale to the data throughput needed for millions of rollups without compromising on security for end users.

Rollups are a relatively new type of blockchain. What makes them different is that they offload some of their work to a layer 1 like Celestia. The simple version is that rollups publish their transaction data to Celestia, which gets ordered and made available for rollup users to download. As a bonus, rollups receive some of Celestia’s security.

But rollups on Celestia aren’t quite the same as others. They are convenient to launch like layer 2s with the added sovereignty that layer 1s enjoy. We like to call these blockchains sovereign rollups.