Every payment app, fintech product, and financial workflow on Arc holds USDC. For most of those applications, those balances sit idle between transactions, generating no return for the users who hold them, and no differentiation for the builders who built the product.

Turning idle USDC into yield has historically required a DeFi infrastructure team to work on lending protocol integrations, smart contract audits, risk parameter decisions, and ongoing maintenance. For most builders, this is overhead and distracts from their main product.

Arc Earn Kit removes that overhead and makes those funds productive.

What Earn Kit does

Earn Kit is an integration layer that connects app balances on Arc to Morpho Vaults through a small set of API calls. The core operations like deposit, earn, track, and withdraw are exposed as developer-facing APIs so integrators don’t need to interact with lending protocol contracts directly, manage risk parameters, or build DeFi-specific infrastructure.

The integrator owns the user experience while Morpho is the noncustodial credit network operating underneath and returning yield to users.

"Every app on Arc will be sitting on idle USDC, but turning that into yield has historically required a DeFi infrastructure team. Arc Earn Kit changes that. With a few API calls, any developer can give their users access to yield from Morpho Vaults to build their own DeFi mullet, fintech in the front, Morpho in the back, with zero development overhead." — Merlin Egalite, Co-founder & Head of Integration, Morpho

Why Morpho

Choosing the right underlying lending infrastructure matters because integrators are trusting it with user funds. Arc chose Morpho as its lending infrastructure partner since it provided:

• Scale and institutional adoption: Morpho holds $17B+ in deposits and serves as the default onchain credit infrastructure for Coinbase, Robinhood, Kraken, Gemini, Societe Generale, and 90+ builders. The depth of institutional adoption reflects the security and operational track record that enterprise-grade applications require.
• Immutability and formal verification: Morpho's core protocol is immutable, meaning deployed contracts cannot be changed after the fact. The codebase has been audited by Cantina, ChainSecurity, OpenZeppelin, Spearbit, and Trail of Bits, and formally verified by Certora. For integrators building financial products, this means the infrastructure underneath Earn Kit carries the same audit rigour expected of any serious financial protocol.
• Curated risk: Yield in Morpho Vaults comes from global borrowing demand, but not all borrowing demand carries the same risk profile. Vault curators like Galaxy Digital, Steakhouse, and Gauntlet manage risk parameters, collateral selection, and market allocation on behalf of depositors. Integrators using Earn Kit can expose users to yield that has been professionally risk-managed without having to operate that function themselves.
• A proven embedded Earn playbook: Morpho already powers embedded Earn experiences for fintechs and consumer apps. Arc Earn Kit brings the same model to the USDC-native chain.

How it Fits the Arc and the Circle stack

Earn Kit is USDC-native by design and makes use of USDC as Arc's gas token and the primary unit of account across the ecosystem. 

Earn is denominated in the asset users already hold so there is no token conversion step, no secondary asset exposure, and no friction between holding USDC and earning on it. Likewise, it is composable with CCTP, Gateway, and the Circle stack.

What this means for builders

For developers building payment apps, treasury tools, neobank products, or any financial application on Arc, Earn Kit changes the calculus on yield features. The question shifts from "do we have the DeFi infrastructure capacity to build this?" to "which vault profile fits our users' risk tolerance?"

Here are a few of many integration directions builders can take:

• Consumer payment apps: User balances that sit between sends can earn passively while the integrator decides how to best fit the feature into its UX.
• B2B treasury and payroll tools: Enterprise USDC balances held between disbursements can be deployed to yield without building lending integrations or making protocol-level risk decisions.
• Savings accounts: A product can add a savings feature with yield incentive without standing up a separate DeFi stack.

Get started with Earn Kit

Arc Earn Kit is available for builders on Arc. Visit the Arc docs to explore Earn Kit's integration guide, and join the Arc community on Discord to connect with the team and other builders working with Earn Kit.

To learn more about Morpho's infrastructure and vault ecosystem, visit morpho.org and the Morpho developer docs.