Skip to main content
Vaults.fyi reads vault state directly from the blockchain every hour. This direct indexing approach — rather than relying on third-party data APIs — is what gives yield figures their accuracy and independence from self-reported protocol numbers.

​
The indexing pipeline

Each hour, Vaults.fyi executes specialized smart contracts that fetch and transform vault data in a single function call. These contracts are deployed as static calls: they execute transiently without writing to blockchain storage, so they cost no gas and leave no on-chain footprint. This architecture has two key advantages over standard multi-call patterns:
  • Efficiency: One result can feed the next calculation within the same call. Standard multi-call requires separate calls for each value.
  • Accuracy: Share prices are read at a consistent block height, so all values used in a single APY calculation come from the same chain state.
Once retrieved, data is stored in the Vaults.fyi backend database for use in APY calculations and API responses.
Vaults.fyi uses Infura, Alchemy, and Ankr as RPC providers. Requests are distributed across providers to maximize reliability and minimize the impact of any single provider’s downtime on data freshness.

​
How share price is read by vault type

Different vault standards expose share price through different contract interfaces. Vaults.fyi handles each type explicitly.
ERC-4626 is the standard interface for tokenized yield-bearing vaults. Vaults.fyi calls two functions directly:
  • totalSupply() — returns total shares outstanding
  • totalAssets() — returns the total value of assets held by the vault
Share price is then totalAssets / totalSupply.
For vaults that predate or do not implement ERC-4626, Vaults.fyi derives equivalent values from other contract functions — typically mint, deposit, burn, or redeem. These functions expose the relationship between shares and assets in their parameters or return values.Each non-standard vault may require individual integration work. The functions listed above cover the most common cases, but some vaults have unique interfaces.
For LSTs such as Lido stETH and LRTs, Vaults.fyi uses totalSupply() and getEthValue(totalSupply()) to determine total shares and total value respectively.LSTs often update their earnings in periodic batches rather than continuously. When a batch posts, the share price jumps sharply, which can inflate the 1-day APY reading for that window. The 7-day and 30-day windows smooth this out — see Calculating APY for how irregular update intervals affect trailing averages.
Rebasing vaults, such as Aave aTokens, increase the user’s token balance directly rather than increasing the share price. The share-to-value ratio is inverted compared to standard vaults.Vaults.fyi reads these using:
  • scaledTotalSupply() — treated as total shares
  • totalSupply() — treated as total shares value
This reversal is necessary to correctly compute the share price growth that underlies APY calculations.
Some vaults, such as StakeWise, do not compound interest automatically. Users must manually harvest and redeposit rewards. Because the shares-to-value ratio does not reflect actual yield in these vaults, Vaults.fyi simulates share price using a derived formula:
total principal value = sETH2.totalSupply()
total rewards value   = rETH2.totalSupply()
TVL                   = total principal value + total rewards value
share price           = 1 + rETH2.rewardPerToken()
totalSupply           = TVL / share price
The totalSupply value produced here is a simulation — it is not read directly from the contract. This lets Vaults.fyi apply the same APY formula consistently across vault types.
RWA vaults are ERC-20 tokens that represent interests in off-chain financial assets. Share price cannot be derived from on-chain balances alone — it requires oracle prices for both the RWA token and its underlying stablecoin.Vaults.fyi uses three functions:
  • totalSupply() — total shares
  • RWAOracle.price() — price of the RWA share in USD
  • StablecoinOracle.price() — price of the underlying deposit asset in USD
Total value in asset terms is then:
total shares in USD   = total shares × RWA oracle price
total shares in asset = total shares in USD / stablecoin oracle price
total shares value    = total shares in asset

​
Data freshness

Vaults.fyi indexes all vaults on an hourly cadence. API responses reflect the most recent hourly snapshot. Because Vaults.fyi reads directly from chain rather than consuming third-party data feeds, yield figures are not subject to delays or data gaps introduced by intermediate data providers.
APY values in API responses represent the state at the last hourly index. If a vault’s on-chain state changed in the past hour — for example, due to a large deposit or an earnings update — the API will not reflect that change until the next indexing cycle completes.

​
Why direct indexing matters

Many yield aggregators source APY data from protocol APIs or front-end endpoints, which can return model-based or forward-looking rates rather than realized yields. Vaults.fyi reads raw contract state and derives all yield figures from first principles. This means:
  • No dependency on protocol reporting: Vaults.fyi does not rely on a protocol to correctly report its own APY.
  • Consistent methodology: Every vault uses the same trailing share price calculation, regardless of how the protocol presents its own data.
  • Verifiability: Any APY figure Vaults.fyi reports can be reproduced by anyone with access to an archive node and the block heights used in the calculation.