Unichain is an Ethereum-based L2 blockchain developed by Uniswap Labs, built as an optimistic rollup using the OP Stack. Under the slogan “The DeFi Chain,” Unichain introduces a novel rollup mechanisms to address challenges facing the DeFi ecosystem. Transactions on Unichain are 95% cheaper than on Ethereum mainnet, reducing costs for LPs and enhancing capital efficiency. Launched as a Stage 1 rollup, Unichain meets minimal trust assumptions and allows anyone to submit fault proofs from Day 1.
What problems is Unichain structurally trying to solve at the infrastructure level that necessitated building a new rollup? By reverse-engineering Unichain's rollup architecture, we can summarize the problems they've identified as follows:
First, transaction ordering for most L2s is not easily verifiable.
Second, fragmented liquidity creates market inefficiencies.
Ultimately, Unichain’s problem recognition converges on a single goal: to meaningfully improve the poor user and developer experience in DeFi. To address this, Unichain proposes two core directions. The first is verifiable block building combined with TEE-based priority ordering, and the second is support for native interoperability.
In the following sections, we explore the background behind the problems Unichain aims to solve, and examine the technical implementation of verifiable block building. We also take a closer look at UVN (Unichain Validation Network), which Unichain introduces to create faster finality.
1.1.1 Liquidity Fragmentation
Ethereum has successfully built an L2 ecosystem including Optimism, Arbitrum, Base, and Abstract based on a rollup-centric scaling solution. The L2 ecosystem now contains over 140 L2s, each specialized in various sectors like consumer apps, RWA, and DeFi, or functioning as general-purpose chains, forming an extensive ecosystem under Ethereum's security layer.
Source: L2beat
As a result of this rapid L2 ecosystem activation, L2 transaction share in the Ethereum ecosystem increased from approximately 35% in early 2023 to 89% within a year. Similarly in 2025, while Ethereum L1 processed an average of 1.3M daily transactions, L2s handled 18M transactions, processing about 13-14 times more than L1.