Arc plugs Morpho Vaults into its Earn Kit SDK for USDC yield

Arc, the layer-1 blockchain developed by Circle, has rolled out its Earn Kit SDK. The kit lets developers connect USDC sitting in Arc apps directly to curated Morpho Vaults so users can earn interest.

What the Earn Kit actually does

The Earn Kit SDK is part of Arc’s broader App Kits suite. Its job is narrow and practical: embed USDC and EURC earning features inside applications without forcing builders to become DeFi engineers.

Developers skip several chores that normally come with offering yield. There is no need for custom DeFi protocol integrations, no vault contracts to write and no markets to bootstrap from scratch.

Instead, the SDK takes care of the plumbing. It handles vault discovery, deposits, position tracking and withdrawals on the developer’s behalf.

For builders, the interface is a set of TypeScript methods. Functions such as exploreVaults and deposit stand in for the smart contract code that would otherwise be required.

The setup is non-custodial. Users keep control of their funds through their own wallets, and their USDC sits in vault contracts rather than with the app or Arc.

Early numbers and partners

Day-one deposits topped $150 million across USDC and EURC vaults.

Two integrations are already on the board. Pulsar Money Earn and SafePal have both connected to the framework.

On the vault side, curators include Steakhouse Financial and Galaxy. Curators decide how deposited funds are allocated across lending markets, so the quality of curation largely shapes what depositors are actually exposed to.

At launch, the supported opportunities involve lending backed by ETH and BTC collateral. In plain terms, depositors’ stablecoins are lent to borrowers who post Ethereum or Bitcoin as security.

The kit also supports cross-chain deposits facilitated by CCTP, along with gas sponsorship. That means users may not need to hold a separate token just to pay transaction fees.

The SDK went live on testnet shortly after it was announced on approximately September 16, 2026. Full mainnet deployment is expected by late September 2026.

Why Morpho sits at the center

Morpho was established as Arc’s primary credit layer on around September 16, 2026. The Earn Kit is essentially the developer-friendly front door to that credit infrastructure.

Morpho’s role on Arc goes beyond passive yield. It provides variable-rate lending and borrowing, which gives the network a native place for stablecoin capital to find borrowers.

Arc’s App Kits are built around a cluster of stablecoin functions: funding, earning and borrowing. The Earn Kit fills in the earning piece of that puzzle.

What this means for builders and users

There are risks worth keeping in view. Yield from lending is only as sound as the collateral and the curation behind it, and launch-stage opportunities are concentrated in ETH- and BTC-backed loans.

A sharp drop in either asset would test the liquidation mechanics of these vaults. The non-custodial design protects users from an app misusing funds, but it does not shield them from market risk inside the vault itself.

The things to watch are fairly concrete. First, whether mainnet arrives on the expected late-September timeline. Second, whether more apps follow Pulsar Money Earn and SafePal in plugging in.

Third, whether deposits keep climbing beyond the $150 million opening mark across USDC and EURC vaults. Finally, if Arc expands beyond ETH and BTC backing, the risk profile of these vaults will shift, and developers will need to decide which opportunities they are comfortable putting in front of their users.