Founders Fund– and Galaxy Ventures-backed Bitcoin ZK-rollup Citrea launched its mainnet on Tuesday, enabling BTC-collateral lending, BTC-structured products and a new US dollar stablecoin, ctUSD, to turn idle Bitcoin into base collateral for DeFi and payments. The launch coincided with a company post on X that outlined early product availability (Citrea’s post).
The network expects about $50 million in active DeFi liquidity in the first weeks, with lending, structured products and decentralized trading live at mainnet start. ctUSD is issued by MoonPay, backed 1:1 by cash and short-term U.S. Treasurys, and integrated with banking rails including vIBANs for fiat onramps and onchain settlement.
Chainway Labs co-founder and CEO Orkun Mahir Kılıç said ctUSD was “natively issued” on Citrea and wired into MoonPay’s Iron banking setup. He added that native issuance reduced bridge risk and made ctUSD the preferred stablecoin on the rollup, rather than a bridged asset.
Citrea reported that testnet data availability at one point used nearly 10% of Bitcoin’s monthly data bandwidth (Ed. note: this showed how rollups can quickly consume block space). Data shows this usage on Citrea’s tracker here.
The mainnet launch revived debate over Bitcoin block space and use cases. Jameson Lopp called it “the next grand experiment in generating sustainable demand for block space.” A critic countered that activity runs on Citrea’s EVM while Bitcoin stores proofs, calling Bitcoin a “filing cabinet” for rollup receipts and warning about a single sequencer, off‑chain treasury and a 10‑party federation (Lopp’s post, this reply).
