TL;DR
Citrea is the first rollup that enhances the capabilities of Bitcoin blockspace with zero-knowledge technology, making it possible to build everything on Bitcoin.
Citrea requires no changes to the network's consensus rules. Citrea and Clementine have been live on Bitcoin Testnet4 since September 2024.
Citrea is a rollup on Bitcoin
Citrea is a rollup. It regularly submits batch proofs to Bitcoin - which also include the state differences for each batch, meaning that any changes from the start to the end of a batch are also available for anyone reading Bitcoin.
A Citrea full node can read the state differences and reconstruct the state directly from Bitcoin - unlike sidechains, in which only small cryptographic commitments are posted and it is impossible to reconstruct the state using that data.
Citrea uses Bitcoin as a Data Availability layer, and it's the only source of truth for the system. As long as Bitcoin is secure, the state of Citrea will be accessible and reconstructable.
Citrea is a Type 2 zkEVM
Citrea is EVM-compatible. As a developer, you can write & deploy your smart contracts in Solidity using the standard EVM tooling.
Citrea processes a large number of zkEVM transactions off-chain. In batches, using these transactions, it generates succinct STARK proofs (later wrapped into succinct SNARK proofs). These proofs are then published to Bitcoin directly. This allows for easy client side verification of the batch validity in an inscription-like envelope.
Citrea's currency is Bitcoin
Citrea uses Bitcoin as its native currency. To avoid confusion and improve on/off-ramp UX, Citrea’s native Bitcoin is referred to as Citrea Bitcoin, $cBTC in short.
Citrea uses $BTC (cBTC) as its native token. To avoid confusion and improve on/off-ramp UX, Citrea’s native $BTC is referred to as $cBTC. There is no Citrea token. Please beware of scams!
Citrea is designed to scale Bitcoin
As a separate execution layer, Citrea has different properties compared to Bitcoin and Ethereum. As an independent execution layer, it offers higher throughput, richer smart‑contract functionality, and lower fees than Bitcoin’s base layer, while still anchoring finality to Bitcoin.
Execution
zkEVM
EVM
Bitcoin Script
Settlement
Bitcoin
Ethereum
Bitcoin
Data availability
Bitcoin via State Diffs
Ethereum
Bitcoin
Fees & Currency
BTC (cBTC)
ETH
BTC
Citrea has a native trust-minimized two-way peg: Clementine
Clementine is the BitVM-based trust-minimized two-way peg mechanism of Citrea. It uses Light Client Proofs that include recursively proven Citrea batch proofs, which enables optimistic ZK Proof verification on Bitcoin using BitVM.
Clementine is trust-minimized as it has a 1-of-N trust assumption, which means that as long as one single entity in the bridge verifier set is honest, no party can steal the pegged BTC from the bridge.
Clementine is deployed on Citrea testnet. You can read more about Clementine here.
Citrea is audited & fully open-source
Citrea & Clementine are built in public.
Both Citrea and Clementine codebases are open-source:
Both Citrea and Clementine codebases are audited as of October 2025.
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