Introducing sovereign rollups to developers

It’s been a short while since we deployed Mamaki, the Celestia testnet. With a successful launch, we rolled out our alpha data availability API and introduced data availability sampling - a key ingredient in Celestia’s scalable architecture.

In the meantime, we introduced sovereign rollups to the world - a new class of rollups that combines the sovereignty of an L1 with the shared security of a rollup.

Today, we are excited to introduce early access technology for sovereign rollups to developers.

Let the rollup experimentation begin!

TLDR

• Documentation is now available to begin building “pessimistic” sovereign rollups with early access Optimint.
• There are two tutorials to start with: an example Wordle game and CosmWasm integration for building smart contracts in Rust.

Freedom to fork

As seen on Ethereum, rollups have a set of smart contracts on the L1. A rollup will publish its blocks to the smart contracts on Ethereum, which validate and append them to its canonical chain. In addition, the rollup has an enshrined trust-minimized bridge with Ethereum for deposits and withdrawals between the two chains.

Sovereign rollups are a departure from the norms of rollups as we know them. There is no set of smart contracts that the sovereign rollups refer to on Celestia. Instead, sovereign rollups publish their blocks as raw data directly onto the chain. Now, nodes on the sovereign rollup are responsible for reading the blocks and verifying a local fork choice rule to determine the canonical chain. This moves settlement from the L1 up to the rollup.

There is no enshrined trust-minimized bridge between a sovereign rollup and Celestia. Uniquely, sovereign rollups gain an independent upgrade path via forking. Forks can be instantiated through the sovereign rollup’s social consensus, enabling easier social coordination and more secure upgrades than non-sovereign rollups.

Create your sovereignty

Sovereign rollups aren’t going to build themselves. To facilitate the ease at which developers can build sovereign rollups on Celestia, we created Optimint, an ABCI client for Cosmos SDK chains to become rollups. Typical Cosmos blockchains use Tendermint for consensus. However, rollups don’t need a full BFT consensus mechanism because Celestia provides consensus.

Optimint is a replacement for Tendermint that publishes blocks to Celestia instead of going through the Tendermint consensus process.

Features of Optimint sovereign rollups:

• No new consensus network: Sovereign rollups can deploy without the burden of bootstrapping and maintaining their own consensus network.
• Built using the Cosmos SDK: Optimint sovereign rollups enjoy the extensibility and developer tooling of the Cosmos SDK.
• Customizable execution environment: The execution environment of an Optimint sovereign rollup can be modified or swapped for an entirely new one that is ABCI compatible.

In its current state, Optimint will run a centralized sequencer without fraud proofs. As such, sovereign rollups using Optimint will run in pessimistic mode because nodes will still need to re-execute transactions to check the validity of the chain (i.e. a full node). Decentralized sequencers and fraud proofs are part of our ongoing development process.

Want to start easy? We created a tutorial for developers to spin up a pessimistic sovereign rollup on Celestia with an example wordle game. If you want to kick it up a notch you can deploy a sovereign rollup with the CosmWasm module to begin developing smart contracts in Rust.

A sovereign frontier

At Celestia Labs, we believe that the layer 0 of any blockchain is social consensus. As such, sovereign rollups are truly independent chains in their own right, rather than as scaling solutions for L1s. A multi-chain ecosystem that enables each chain to enact independent decisions via social consensus is the hallmark of a socially scalable system.

Create a sovereign DAO. Build a forkable app-specific rollup, or design a multi-chain NFT marketplace. Explore what is possible with sovereign rollups.

The beginning

For more information about spinning up your own sovereign rollup, head over to our docs page. If you need any help during your testing, drop your questions in the #developers channel on our discord.

If you make your way through the docs and start experimenting with Celestia, give us a shout on twitter or discord. We’d love to hear about what you’re building.

If you are inspired to help us build the first modular blockchain network, Celestia Labs is hiring! A list of our open positions can be found here.