In one of my prior posts, I mentioned how users complain that Urbit needs more apps. The complaints are most likely an issue with app discovery, as the Urbit ecosystem is growing in leaps and bounds. So in this post, I briefly highlight one such upcoming project, Uqbar. Uqbar’s project could make Urbit a foundational layer in the crypto-stack.

Uqbar – Generalized EVM Execution Layer and Crypto OS Layer

At a high level, Uqbar is a generalized execution blockchain where transactions execute on Urbit, post to Starknet, then settle on Ethereum. Uqbar is using Ethereum to bootstrap its blockchain but has plans to transition to an L1 (11 min mark) once it grows.

Uqbar is currently in testing, and much of the design may change. But for now, Uqbar gives Urbit instances native read/write access to their blockchain with zk-proofs, Zere, and Hoon smart contracts. Recall that all code in Urbit is in Hoon and compiles to Nock, and Nock represents the state of an Urbit as an integer. Zere is the zk-version of Urbit’s runtime Vere and can take any Nock integer from a Hoon smart contract and create a zk-proof for it. When an Urbit instance interacts with a Hoon smart contract on Uqbar, they send its transaction to a sequencer, which posts the tx to Starknet.

Sequencers will likely be Urbit Stars which will batch transaction groups. Once sequenced, Stars will post transactions to Starknet and eventually Ethereum. Sybil resistance for sequencers is trivial, as Star-space is limited and highly valuable in the Urbits network.

Uqbar’s design is still largely theoretical – Starknet is still developing its architecture, and Uqbar is only running on a testnet. But if Uqbar goes live, this has the potential to become the Urbits killer app. Imagine an OS with a built-in wallet and the ability to read/write on a blockchain. Concerns around centralized entities like Infrura are, in large part, mitigated. Uqbar can bring DeFi, NFT, crypto-gaming, or anything currently built on smart contract chains to Urbit.

For those wondering, Uqbar will also most likely have a token for gas and security. Documents and talks refer to this token as a Zig, but the name will probably change.

Fair warning, currently, safe use of Uqbar will require a dedicated Urbit instance (like a moon) or a hardware wallet. Data in Urbit is composable and shared across apps. Any app can read the entire state of your Urbit. As such, apps could read any private keys stored in your Urbit. However, this is a known issue, and we expect Urbit to develop some data permissioning to alleviate these issues.

Although their final product is months away, Uqbar is a promising project that I will watch closely.