Cardano Ouroboros Leios: Layer-1 Upgrade to Boost Throughput and Decentralization

Cardano’s Ouroboros Leios aims to raise mainnet throughput from 10–15 TPS toward hundreds, targeting 500 TPS initially, while preserving decentralization and security.

Rich by Coin

2026-02-10

Cardano is preparing a layer-1 upgrade it says will push mainnet throughput from roughly 10–15 transactions per second to hundreds, while keeping the network’s decentralization and security profile intact. At a Tokyo community event on the Midnight Japan Tour, Input Output’s Michael Smolenski and Cardano founder Charles Hoskinson framed Ouroboros Leios as both a scaling step and a broader consensus breakthrough. Smolenski, Cardano Core product manager at Input Output, told attendees Leios is “an upgrade to layer 1 to make Cardano faster,” with active development underway and a target release “this year in 2026.” He described the current throughput ceiling as suitable for proving out Ouroboros’ design, but insufficient for the next phase of adoption and for the economics of stake pool operators (SPOs).

Up until now the speed of the network has been around 10 to 15 transactions per second, Smolenski said. But now we need to move on to higher transaction throughput in order to compete and drive further adoption. Another factor, SPOs, in the long term need to support the cost of their operations from transaction fees instead of from block rewards, they need to see network usage of around 50 transactions per second. The initial Leios mainnet release is pitched as a “50 times improvement,” with Smolenski translating that into an early move from roughly 10 TPS to around 500 TPS.

Rather than sticking to transactions-per-second as the headline metric, he emphasized “transaction kilobytes per second” to account for varied transaction sizes, calling out a target of “300 transaction kilobytes per second” and a confirmation window “between 20 to 80 seconds,” based on prototype results. Smolenski described Leios as Cardano’s “next generation consensus protocol,” built around additional block types. “There’s a new block. It’s called an endorser block,” he said, adding that existing blocks would be referred to as “ranking blocks.” The practical consequence, in his telling, is the ability to “pack a whole lot more transactions” by bundling them into endorser blocks, alongside other prioritization mechanics he did not detail on stage.