Aave V4 went live on the Ethereum mainnet in late March 2026, replacing the old unified pool model with a three-layer structure built around hubs, spokes, and credit lines. According to Aave's documentation, the redesign separates liquidity storage from market logic to improve scalability and risk isolation.
Hubs: Immutable Core Ledgers
Hubs are smart contracts that hold user-supplied assets and track total deposits and loans. Each hub maintains its own balance sheet, independent from others on the network. A critical design choice: hubs cannot be upgraded after deployment. This locks the core accounting logic but does not prevent governance from registering new assets inside a hub via voting. Every registered asset receives a unique identifier for cross-market tracking. At launch, three hubs operate on Ethereum: Core, Prime, and Plus. Core serves basic lending needs, Prime offers better rates, and Plus targets high-barrier strategies. Liquidity is segmented across these hubs but remains accessible through spokes.
Spokes: Upgradeable User-Facing Interfaces
While hubs store assets, spokes handle all user interactions — supplying, borrowing, repaying, and withdrawing. Each spoke defines its own risk parameters, including collateral factors, liquidation thresholds, and interest rate models. The key difference: spokes can be upgraded over time through governance votes, without touching any hub contract. This allows risk parameters to be adjusted quickly as market conditions evolve. A single hub can support multiple spokes simultaneously, each with distinct configurations. For example, one spoke may accept a certain token as collateral while another does not. This enables a shared liquidity pool to power multiple markets, each with its own risk profile.
Credit Lines: Per-Asset, Per-Channel Borrowing Caps
Hubs and spokes are linked by credit lines. Each credit line sets a borrowing limit for a specific asset. A spoke can only draw liquidity up to that cap. These limits are applied per asset and per hub connection — borrowing USDC and USDT creates separate credit lines, each with an independent cap. The hub enforces these limits on every transaction. Moreover, a single spoke can access multiple hubs through different credit lines, giving governance the flexibility to adjust market exposure by raising or lowering these caps. This design provides granular control over liquidity access while maintaining strict exposure limits.
Aave V4's hub-spoke-credit line architecture marries the immutability of asset vaults with the flexibility of market logic. Hubs secure the core ledger, spokes adapt to changing conditions, and credit lines act as precise valves. Whether this system can survive extreme market stress will depend on the fine-tuning skills of its governance.