Circle said its Arc Layer-1 blockchain will launch its public mainnet on September 16, 2026, with Uniswap v4, liquidity pools, swap routing, and developer SDK and API tools integrated from launch. Arc is designed as financial infrastructure and a settlement network for global markets, with a focus on stablecoin activity. Its testnet has processed more than 500 million transactions across nearly 3 million wallet addresses, while more than 100 partners are active on the private mainnet. Arc's design includes direct 1:1 swaps between stablecoins such as USDC, USDS and DAI, USDC as the gas token, and deterministic finality in under one second. The network's initial validators are expected to operate it alongside Circle. Uniswap's deployment supplies an established liquidity layer, while its v4 hooks allow customized pool behavior for fee models, oracle integrations and compliance-oriented workflows. Curve and Aave are among the partners involved in Arc's development, giving the network a broader DeFi infrastructure base as Circle continues building an ecosystem for decentralized and institutional financial use cases.