The next gear for Cardano's throughput.
Ouroboros Leios is the next chapter of Cardano’s consensus protocol. A new way of moving transactions through the network. One that multiplies throughput by orders of magnitude, preserving Cardano’s proven security guarantees. Built by Input Output Research. Peer-reviewed. Engineered to last.
Specialist Partner
Ensurable SystemsInput Output Research (IOR) leads the protocol design, the formal models, and the peer-reviewed publications behind Leios. Ensurable Systems takes the specification through to production: Haskell implementation, performance benchmarking, and integration with the existing Cardano node. Research and engineering, named and accountable, with milestones published as they are verified.
What Leios Is
Today, Cardano processes transactions sequentially, predictably, securely. Leios takes it a step further with parallel processing. It splits how transactions travel the network from how they get confirmed on-chain, so both happen at once, at scale. For the teams building on Cardano, that is a new gear. More room to build. Faster settlement. A network moving at the speed of the work being done on it.
What Leios Delivers
A 10 to 65x increase in transaction throughput capacity over today’s network. Parallel block propagation that scales with available bandwidth, not just block size. Confirmation guarantees that match the security properties Cardano users already depend on. A consensus layer DeFi protocols, payment platforms, and enterprise applications can grow into, not out of.
Why It Matters
For the DeFi protocols, DApps, and institutions building on Cardano, Leios is the upgrade that opens the runway. It is engineered to lift Cardano from roughly 800,000 transactions a month to the 27 million the 2030 roadmap calls for. That is a 10 to 65x leap in capacity. A new tier of network. The kind payment platforms, on-chain finance, and serious enterprise applications can grow into without ever looking back.
What’s Live / What’s Next
Where we are:
Leios is in active development. The full protocol specification is published, open for the community to read, review, and shape, the way every Cardano upgrade has been built since day one. A public testnet is targeted for this summer.
What’s next:
Engineering implementation is underway. Mainnet deployment is targeted for 2027.
Roadmap
Specification, benchmarks, and milestone reports published openly. Mainnet deployment subject to community review and on-chain governance.
2025
Protocol spec published and peer-reviewed
Summer 2026
Public testnet live, open benchmarking
Late 2026
Audit, hardening, implementation finalization
2027
Mainnet deployment