Sei Proposal Targets 200,000 Transactions per Second Through Autobahn Consensus
Key Facts
On October 28, 2026, Sei published proposal SIP-6 to change how blocks are built on the network, moving from a single proposer to an Autobahn architecture that allows two proposers to operate concurrently. As part of its Giga plan, the design targets performance of 200,000 transactions per second and finality in under 250 milliseconds. But the proposal document labels it a "draft," meaning the change has not yet been accepted or implemented. The document says the published figures are targets, not fixed guarantees of latency or throughput. The figures therefore remain a projection of the performance Sei aims to achieve, not a description of the network’s current performance.
According to Sei’s explanation, Autobahn is based on a continuous stream of transactions from the 40 validators, with each validator sending what it receives through its own lane. SIP-6 divides the work into concurrent lanes for transaction availability, ordering and execution, rather than waiting for each stage to finish before the next begins. The proposal says this overlap allows block publication, ordering and execution to occur concurrently. CommitQC establishes transaction order, while AppQC attests to the execution state. After transactions are ordered deterministically, the design assumes validators will reach the same result. The proposed distribution of work would therefore change, while the network currently continues to use a single block-building mechanism.
Sei links the multiple lanes to reducing reliance on a single proposer for transaction inclusion, and says deterministic ordering limits some opportunities for maximal extractable value. However, the SIP-6 specification sets a clear limit on this point, stating that Autobahn "does not eliminate MEV or provide a general guarantee of fair ordering." This means that, according to the proposal, changing the consensus architecture does not eliminate the practice or guarantee fair ordering in all cases. This remains an aspect of the proposed design, not a proven outcome on mainnet. Sei presents these features among the reasons for the change, alongside its performance target.
SIP-6 is part of the Giga plan, which Sei describes as a rebuild of the execution, storage and consensus layers. The company says the first two stages of its execution and storage work, Ares and Eidos, are already operating on mainnet. Autobahn addresses the consensus layer and aims to shift block building from one validator to concurrent validator lanes. On August 19, 2026, EL7 published a report on the start of the Eidos upgrade, noting a target throughput of 200,000 transactions per second. This sequence places Autobahn within broader work spanning more than one layer, while the published throughput target remains tied to Sei’s future Giga plan.
Autobahn is currently available only on Sei Labs’ internal testnets, according to the company’s announcement. Sei says the next step is to make a public testnet available to validators and application teams so they can test the system and try to find weaknesses. Before launch on mainnet, SIP-6 must be accepted through Sei’s proposal process, alongside independent audits and fixes for defects classified as critical and high severity. Requirements also include training on a copy of the real network state and publishing hardware and bandwidth requirements. The company says the network’s status will not change for users before Autobahn runs on mainnet, and that one validator will continue to build every block until then.
There is another prerequisite before activation: Sei says completion of the Cosmos retirement under SIP-3 must precede Autobahn’s launch. The SIP-6 announcement did not set a mainnet launch date, leaving the timing of the transition dependent on proposal acceptance and completion of the tests, reviews and prerequisites. After Autobahn, Sei describes the Hermes upgrade as a planned consensus step on top of it, aimed at accelerating finality further. In the coin market, SEI rose 0.47% in the October 28 session, after falling 8.45% on October 22. The data summary recorded a decline of 32.5787% from September 28 to October 28; these figures do not establish that the SIP-6 proposal caused the price movement.