Scalable
Optimizes network bandwidth for faster transaction processing, significantly enhancing Cardano’s scalability. Transactions are confirmed with minimal delays for a seamless user experience.
Secure
Preserves Ouroboros' strong security properties with robust defenses against attacks while ensuring fair participation.
Decentralized
Improving the throughput by 50x while not compromising decentralization. So, the network still will maintain its resiliance, fairness and democratisation.
From Research to Reality
The published Leios CIP represents a strategic balance between throughput gains and ecosystem compatibility
The proposed Leios specification delivers a 30-50x throughput increase (from ~4.5 TxkB/s to ~140-300 TxkB/s) while maintaining manageable ecosystem impact. Unlike the research paper's approach, which achieves higher throughput but requires extensive ecosystem changes and 2-3 minute confirmation times, the CIP specification strikes a strategic balance.
Key advantages of the CIP approach include modest latency increases (45-60 seconds vs 20 seconds), familiar transaction structures for ecosystem compatibility, and a realistic 1-1.5 year deployment timeline compared to 2.5-3 years for higher-concurrency alternatives.
How Leios Works
Block producers simultaneously create both a standard Praos block and a larger secondary block referencing additional transactions
Ouroboros Leios achieves higher transaction throughput by allowing block producers to create additional blocks alongside the regular Praos chain. These supplementary blocks, called Endorser Blocks (EBs), reference extra transactions that would otherwise wait for the standard Praos blocks (called Ranking Blocks or RBs) in this protocol in future active slots.
To ensure data availability and correctness, these blocks undergo committee validation before their transactions become part of the permanent ledger. The key insight is that we can maintain Praos's security guarantees while processing more transactions by carefully managing when and how these additional blocks are validated and included in the chain.
EB inclusion is opportunistic rather than guaranteed, depending on the random timing of block production relative to the certification process. This design preserves the existing Praos chain structure while adding substantial transaction capacity through the secondary validation pathway.
Stay up to date
Catch up on the latest Leios progress, key decisions, and Q&A in our monthly review videos
Catch up on past reviews
Live Development Tracker
Follow the real-time progress of Leios development with our interactive tracker
Our live tracker provides transparency into the ongoing Leios development work. See current sprint progress, completed milestones, and upcoming tasks as the team builds towards the next generation of Cardano consensus.
The tracker observes GitHub commits in real-time, giving you direct insight into the engineering work happening across simulations, specifications, and implementation efforts.
Mempool Simulation
Explore how transactions propagate through the Cardano network with our interactive simulation tool
The mempool simulation visualizes how transactions flow through a simplified model of the Cardano network running Ouroboros Praos. Watch as transactions are submitted, propagated between nodes, and eventually included in blocks.
This tool helps illustrate current network behavior and provides a foundation for understanding how Leios will enhance transaction throughput. While it doesn't yet incorporate Leios-specific features, it demonstrates the baseline mempool dynamics that Leios aims to improve.