Architecture

How we built the fastest flashblocks implementation with 5X higher throughput, zero reorgs, and the industry's fastest RPC sync At X Layer, we're building the infrastructure for the next generation of onchain applications. Speed matters — and not just perceived pre-confirmed speed, but real, chainstate finality. In January 2026, we shipped Flashblocks on X Layer mainnet and made X Layer 5X faster, reducing the effective transaction and chainstate finality from 1 second to just 200 milliseconds — while simultaneously achieving the highest flashblocks sequencer throughput among all OP Stack chains . This post is a technical deep dive into the engineering details of Flashblocks. We will provide an in-depth walkthrough of our custom flashblocks builder integration on X Layer sequencers, the zero-reorg protection system that guarantees flashblock finality, and the industry-leading RPC architecture that delivers ultra-low latency chainstate updates to downstream consumers.