Cardano Hydra
Cardano Hydra is a family of layer 2 protocols for the Cardano blockchain, and its main part, the Hydra Head, lets a small group of participants process transactions off the main chain. The participants lock funds on Cardano, transact among themselves with confirmations in well under a second and later write the final state back to the main chain.
Input Output develops Hydra as open source, and the Hydra Head protocol has been ready for production use since version 1.0 in October 2025. On the main chain itself, Leios is planned to raise throughput and Peras to shorten settlement, while Mithril already lets nodes start from certified snapshots.
How a Hydra Head works
A Hydra Head opens when its participants commit funds from the main chain to a script. Inside the head they exchange transactions under the same eUTXO ledger rules as on Cardano, so existing smart contracts run without changes. Any participant can close the head at any time, and after a contestation period the latest agreed state returns to the main chain. A head needs every participant online and in agreement, which suits payments between known parties such as a merchant and a payment provider.
Hydra 1.0, release date and TPS
The Hydra Head protocol reached version 1.0 in October 2025, after several years of public releases on GitHub. Its throughput in transactions per second depends on the number of participants and the size of the transactions, because each head runs on its own. Several heads can run in parallel, so total throughput grows with the number of heads, and each head confirms its transactions in well under a second.
Leios: more throughput on the main chain
Ouroboros Leios changes the consensus protocol of Cardano so that the main chain itself can carry more transactions. Linear Leios, specified in CIP-164, adds endorser blocks, larger blocks of transactions that the regular ranking blocks certify. Input Output Group targets mainnet in December 2026 through the Dijkstra hard fork, which still needs approval through Cardano governance.
Peras and Mithril
Ouroboros Peras lets stake pools vote on recent blocks, which shortens the time until a transaction counts as settled to about two minutes. Reports place it in a later hard fork, around the second quarter of 2027. Mithril uses stake-based threshold multisignatures to certify snapshots of the chain, so a new node or a light wallet can start from a certified state and skip replaying the full history.
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Cardano Hydra and Finance Loop
Finance Loop covers blockchain scaling in the Digital Infrastructure & Sovereignty track, where infrastructure teams of banks and payment providers compare throughput and settlement times. Hydra Heads move payments between known parties off the main chain, and Leios raises the capacity of the main chain itself.
Finance Loop is a professional network and has the goal of driving the institutional use of emerging technologies in finance, such as AI, digital payments, cloud and blockchain solutions. Finance Loop helps its members build skills and personal networks in these fields: Investment & Digital Assets, Payments & Digital Money, Digital Infrastructure & Sovereignty, and Risk & Compliance.