Arc Launches Earn Kit With Morpho Vaults for USDC, EURC Lending

Arc has launched Earn Kit, a TypeScript software development kit that lets wallets, exchanges and fintech apps add USDC and EURC lending features through Morpho vaults without building separate decentralized finance integrations.

The toolkit combines opportunity discovery, deposits, withdrawals, position monitoring and yield-or-loss tracking in one interface. It also supports cross-chain deposits through Circle’s Cross-Chain Transfer Protocol and gas sponsorship through Gas Station for Circle Wallets.

At launch, Earn Kit supports Morpho-based vaults on Arc, including markets backed by Ether (ETH) and Bitcoin (BTC) collateral. Morpho deposits on Arc exceeded $220 million on day one and topped $500 million at the time of its Oct. 8 update.

“Earn Kit gives teams a simpler path: embed USDC and EURC lending opportunities offered by supported third-party protocols through a single TypeScript SDK,” said Elton Tay, Circle’s developer-relations lead.

Morpho vaults direct deposited assets into selected lending markets. Borrowers pay interest on loans secured by collateral, and that interest can increase the value of vault shares. Returns vary and are not fixed rates.

A developer example displayed a 4.2% annual percentage yield on Sept. 13, 2026, at 11:44:07 p.m. ET (03:44:07 UTC on Sept. 14). The example ran on Arc Testnet, so the figure does not represent a guaranteed or current rate.

Wallets retain control of deposited funds. Earn Kit does not custody, own, curate or recommend the third-party lending markets, and vaults are not ranked through the toolkit.

The integration reduces the engineering work required to add yield features, but it does not remove risks tied to lending markets, liquidity, collateral or liquidations. Earn positions interact directly with third-party onchain markets, and deposited assets can be lost.

The launch expands Arc’s developer tools beyond borrowing. Its earlier Borrow Kit example for adding crypto-backed loans showed how applications could add lending features without maintaining a direct integration with a lending protocol.