Rollkit, a “modular framework for rollups,” has claimed over Twitter on Sunday that it has developed a new rollup solution that will allow “sovereign rollups” on the Bitcoin blockchain. The new rollup solution retrieves and stores data on the Bitcoin blockchain, allowing users to produce rollups. Rollkit’s solution was inspired by Ordinals, the Bitcoin NFT protocol which showed developers that—using Taproot—users could post arbitrary data to the blockchain. The goal of this new integration is to expand the possibilities for rollups and also to help bootstrap a healthy blockspace fee market on Bitcoin, enabling a more sustainable security budget.

Traditionally, rollups are batches of transactions that are “rolled up” off-chain into one transaction, then posted to Ethereum as a single on-chain transaction. This helps free up blockspace and lower transaction costs on the network while still inheriting the settlement assurances of the base chain. A sovereign rollup is one that does not need a smart contract or use a settlement layer for validation, making it scalable and secure, with the “sovereignty” of a layer 1.

However, some proponents of Ethereum have taken issue with Rollkit’s use of the term “sovereign rollup.” Ryan Berckmans, a Web3 and Ethereum investor, said on Twitter that the sovereign rollup “is actually an alt L1 that stores its block data on Bitcoin.” According to Alexei Zamyatin, founder of the Bitcoin DeFi protocol Interlay, sovereign rollups as proposed by Rollkit inherit “nothing” of Bitcoin’s security.

Rollkit, however, remains bullish on the possibilities. The company believes that this new integration will help bootstrap a healthy blockspace fee market on Bitcoin, enabling a more sustainable security budget. Some are likening sovereign rollups to Stacks, a high-functionality layer 1 protocol that settles its blocks on the Bitcoin blockchain for security purposes. Stacks co-founder Muneeb Ali said on Twitter that this is an apt comparison but noted some key differences.

One key difference between sovereign rollups and Stacks is that it takes 150 Stacks blocks before a transaction reaches “Bitcoin finality” on Stacks, but only one with sovereign rollups. On the other hand, Stacks blocks publish their data to Bitcoin in an efficient manner by merely hashing the data on-chain, whereas sovereign rollups publish the full data. Ali added that the technically challenging part for both the Stacks layer and sovereign rollups is moving BTC in and out of the layer, with the decentralized BTC peg being the most important part.