BOB, a renowned hybrid L2 blockchain, has announced its new partnership with RISC Zero (a prominent zkEVM platform), Conduit (a rollup-as-a-service provider), and Boundless (a zero-knowledge proof ecosystem). With this collaboration, BOB has become the earliest Hybrid ZK Rollup to redefine efficiency, security, and scalability for the Ethereum-based L2 ecosystems. In its X announcement, BOB has pointed out that this development is a major step to set new benchmark for decentralization, security, and transparency. The milestone merges the strengths of diverse rollup architecture to form a hybrid vision.
Excited to announce that BOB becomes the first-ever 𝗛𝘆𝗯𝗿𝗶𝗱 𝗭𝗞 𝗿𝗼𝗹𝗹𝘂𝗽 in collaboration with @RiscZero @boundless_xyz & @conduitxyz
We believe that BOB’s Hybrid ZK fraud proofs are the best and most efficient proving system in use by any rollup today:
> ZK rollup… pic.twitter.com/8urTRNdYwu
— BOB (@build_on_bob) July 24, 2025
BOB Pioneers New Epoch of Hybrid ZK Rollups
In partnership with RISC Zero, Conduit, and Boundless, BOB’s transition into the 1st Hybrid ZK Rollup unlocks a new epoch of security, scalability, and efficiency to bolster Ethereum L2 networks. This development leverages a unique proof system that merges the finest of zero-knowledge (ZK) and optimistic rollups. This approach combines the cost-efficient optimistic transfers with on-demand validity proofs, guaranteeing rapid finality when required.
Conventionally, rollups are of two types: optimistic rolups and zero-knowledge (ZK)/validity rollups. Optimistic rollups assume transfers are valid while requiring a 7-day window for challenge. However, validity or ZK rollups verify transfers rapidly but with massive operational costs. In this respect, BOB presents a hybrid ZK model to merge the best of both these models in an efficient and cost-effective way.
Setting New Benchmark for Permissionless, Secure, and Scalable Ethereum L2 Solutions
According to BOB, OP Kailua (a cutting-edge extension of the open-source framework) powers this breakthrough. It delivers cost-efficiency, accessibility, speed, and instant withdrawals. Keeping this in view, the upgrade of BOB also unveils a seamless fraud-proof mechanism to settle disputes with a single ZK proof. Overall, the pioneering rollout of BOB as Hybrid ZK Rollup is poised to set an exclusive standard for permissionless, secure, and scalable L2 solutions on Ethereum.
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