Celestia activates Fibre, enabling direct validator uploads for rollups

Celestia has switched on Fibre, a new high-throughput lane for rollup data, on its mainnet. Activation came on approximately October 20, 2026, after validator signaling crossed the required 83.33% voting power threshold. Fibre works as a parallel data availability layer. It is run by the same validator set that already secures Celestia, so no new operators are involved. Data availability is the plumbing that lets rollups prove their transaction data was actually published. Without it, nobody can check that a rollup is telling the truth about its own history. Celestia normally handles this through its L1 “data square,” a structured layout that data gets packed into for each block. Fibre steps outside that process. Blobs, the chunks of data rollups submit, go straight to validators. The checks still happen. Commitments and validator signatures continue to land on-chain, so there is still a public record that the data was received and attested to. The launch numbers The initial release has firm limits. A single Fibre blob can be up to 128 MiB, and each block can hold up to 200 Fibre submissions. There is also a floor. The minimum blob size is set at 256 KiB, which signals that Fibre i...