# Citrea rollup and Clementine bridge by Citrea (Chainway Labs) Canonical page: https://technooptimist.io/crypto/citrea-mainnet Frontier: [Crypto](https://technooptimist.io/crypto.md) · Field: Bitcoin & mining · Company: [Citrea (Chainway Labs)](https://technooptimist.io/companies/citrea.md) Stage: Deploy (4 of 5: Research → Proto → Pilot → Deploy → Scaling) Updated: last update 2026-06-04, facts checked 2026-10-11 Goal: Make bitcoin usable in lending and trading apps without trusting a custodian, by settling a fast app chain on Bitcoin and guarding the bridge so that a single honest party can block any theft. Status: Mainnet since Jan 27, 2026; ~$12M in DeFi deposits (Jun 2026); one sequencer, BitVM bridge live. Next milestone: Decentralised sequencer network ## Milestones | Status | Milestone | Date | Slip | | --- | --- | --- | --- | | Done | $14M Series A led by Founders Fund | 31 Oct 2024 | | | Done | Clementine bridge paper published | 2025 | | | Done | Mainnet, Clementine bridge and ctUSD launch | 27 Jan 2026 | | | Done | CTR token trading on major exchanges | May 2026 | | | Planned | Decentralised sequencer network | | | ## Most important updates - **4 Jun 2026**: Four months in, Citrea holds about $12M in DeFi deposits as its CTR token starts trading. A FalconX market note put Citrea's DeFi deposits at about $12M, described by Citrea as organic and pre-incentive, with ctUSD at about $24M. ([our story](https://technooptimist.io/stories/four-months-in-citrea-holds-about-12m-in-defi-deposits-as-its-ctr-token-63bcffd3.md) · [original source](https://www.falconx.io/newsroom/citrea-ctr-the-bitcoin-zk-rollup)) - **27 Jan 2026**: Citrea launches mainnet with the Clementine BitVM bridge and a MoonPay-issued stablecoin, ctUSD. Citrea went live as a rollup that runs transactions off Bitcoin and uses Bitcoin for settlement. ([our story](https://technooptimist.io/stories/citrea-launches-mainnet-with-the-clementine-bitvm-bridge-and-a-moonpay-a2cc4d1e.md) · [original source](https://forklog.com/en/bitcoin-based-zk-rollup-citrea-launches-mainnet/)) - **31 Oct 2024**: Citrea raises $14M Series A led by Founders Fund to build a ZK rollup for Bitcoin. Chainway Labs, which builds Citrea, raised $14M in a round led by Founders Fund, with angels including Erik Voorhees, Balaji Srinivasan and Jameson Lopp, plus Maven11. ([our story](https://technooptimist.io/stories/citrea-raises-14m-series-a-led-by-founders-fund-to-build-a-zk-rollup-1142fbd6.md) · [original source](https://www.prnewswire.com/es/comunicados-de-prensa/citrea-recauda-14-millones-de-dolares-para-expandir-bitcoin-mas-alla-del-oro-digital-302293116.html)) ## Current obstacles - **Little capital so far**: About $12M in DeFi deposits by June 2026 is small next to bitcoin wrappers holding billions; adoption leans on incentives. - **Centralised ordering**: A single sequencer can censor or stall transactions, and a 3-of-5 security council can upgrade the system. ## Physics limits - **Bitcoin can't verify proofs natively**: Bitcoin script has no opcode to check a zero-knowledge proof, so BitVM must break the check into many steps that are only run on-chain in a dispute. - **Someone must front the money**: Optimistic bridges pay users first and settle later, so operators need idle BTC plus bonds; that tied-up capital has a cost someone must pay. ## How it works ### Peg in: Lock BTC with the signer committee BTC goes to a Taproot address the signers control; if it isn't moved into the vault within 200 blocks, the user can take it back. ### Run: Fast EVM chain cBTC is the gas token; a sequencer orders transactions in 2-second blocks, and the chain's state is proven with zero-knowledge proofs. ### Peg out: Operators front the BTC On withdrawal an operator pays the user on Bitcoin, then claims repayment from the vault by posting a KickOff transaction. ### Challenge: BitVM catches false claims For ~1.5 days anyone may challenge a claim; disputes are settled step by step on Bitcoin, and a cheating operator loses its whole bond. ## Spec sheet | Spec | Citrea rollup and Clementine bridge | Provenance | | --- | --- | --- | | Block time | 2 s | reported | | Block gas limit | 10M | reported | | Bridge operator bond | ~2 BTC | reported | | Payout challenge window | ~1.5 days | reported | | Bridge safe unless attacker holds | >45% of hash rate for 2 weeks | reported | | DeFi deposits (Jun 2026) | ~$12M | reported | | ctUSD supply (26 May 2026) | ~$24M | reported | Provenance: reported = stated by the company; estimated = our estimate; sample = a sample figure. ## Papers and demos - **2025** (paper): [Clementine: A Collateral-Efficient, Trust-Minimized, and Scalable Bitcoin Bridge](https://eprint.iacr.org/2025/776). Design and security proof of the BitVM2 bridge behind cBTC, with Common Prefix, TU Wien and Edinburgh researchers. ## About Citrea (Chainway Labs) Citrea, built by Chainway Labs, is a zero-knowledge rollup that settles on Bitcoin: it runs Ethereum-style apps on its own chain and posts proofs and data to Bitcoin. Its Clementine bridge uses BitVM so that one honest participant can stop theft. - Mainnet launched Jan 27, 2026, with Clementine, a bridge built on BitVM. - Raised a $14M Series A led by Founders Fund (Oct 2024), its first Bitcoin investment. - Small so far: ~$12M in DeFi deposits and ctUSD at ~$24M (May–June 2026). - Headquarters: KY - Status: private - Raised: $14M - Last round: Series A $14M, 31 Oct 2024, led by Founders Fund - Website: https://citrea.xyz - People: Orkun Kilic (Co-founder and CEO, Chainway Labs) - Partners, customers, investors: Founders Fund (investor); MoonPay (partner); Morpho (partner) Company page: https://technooptimist.io/companies/citrea.md ## Related programs Everything in Crypto: https://technooptimist.io/crypto.md --- The Techno Optimist tracks every frontier of technology, program by program: https://technooptimist.io/ (a Markdown version of any page: add .md to its URL; site map for agents: https://technooptimist.io/llms.txt). 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