Sei Drafts Autobahn Plan After Internal Test Shows Sub-250-Millisecond Ordering

Sei published a draft Autobahn plan on Oct. 28, proposing a consensus redesign for parallel validator transaction batches after an internal test recorded ordering in under 250 milliseconds.

Created Oct. 27, SIP-6 is part of Sei Giga and would change how blocks are assembled. Each active validator would maintain a separate lane for proposed transactions. A rotating leader selected by stake would order references to certified lane blocks, while ordering, data availability and execution proceed in overlapping stages.

The design aims to use validators’ combined bandwidth and reduce reliance on one block producer for transaction inclusion and sequencing. The design could limit some censorship and ordering opportunities, but it does not guarantee fair ordering or eliminate the possibility of profit from transaction placement.

An internal devnet with 40 nodes across 20 regions recorded ordering finality below 250 milliseconds and throughput of more than five gigagas per second. The finality figure measures agreement on transaction order. A commit certificate confirms that order, while a later application certificate covers the resulting state; the first certificate does not show that execution succeeded. Performance is not guaranteed and depends on network and workload conditions.

The 200,000-transactions-per-second (TPS) figure is a separate public-testnet target. A May 27 roadmap lists 400 milliseconds as the Autobahn public-testnet finality milestone. SIP-6 does not reconcile that figure with the under-250-millisecond internal-devnet result.

For activation, SIP-6 lists governance approval, completion of SIP-3, independent audits, rehearsal and test results. Sei’s rollout plan also calls for a public testnet. The roadmap lists Autobahn mainnet as coming soon, and Sei has not announced an activation date.