# Noca Savings xDAI

> Noca is an interface for depositing xDAI or WXDAI into the Savings xDAI vault on Gnosis Chain and withdrawing from it. The site helps visitors understand the vault, its variable yield, its relationship to sUSDS, and the costs and risks of using it.

The canonical website is https://sdai.gno.now/. Its main page is the transaction interface. Learn more opens the educational guide as a closable panel over the app, preserving the current app view. The same article is available directly at https://sdai.gno.now/learn/ for reading without JavaScript. Closing the panel returns to the app; a direct visit has a Close link to the app. Noca provides the interface; the configured contracts perform the vault operations. The site is intended for people considering xDAI savings, existing vault holders, and developers checking the Gnosis vault and its ERC-4626 interface.

The app supports Gnosis Chain, chain ID 100. Native xDAI pays network gas. WXDAI is its ERC-20 representation and the vault's underlying asset. Savings xDAI shares currently have the name "Savings xDAI" and symbol "sDAI". Depositing through the app yields shares in this configured vault. A share balance and its redeemable asset value are different quantities; do not interpret a share as necessarily redeemable for exactly one xDAI.

The Ethereum savings strategy relates to Sky's USDS/sUSDS transition. Ethereum sUSDS and the Gnosis savings vault share are distinct assets, with different addresses and chain contexts. This interface accepts xDAI or WXDAI, not arbitrary tokens named USDS or sUSDS. It does not execute an Ethereum savings deposit, a token swap, or cross-chain bridging inside its deposit form. Ordinary xDAI in a wallet is not a Savings xDAI vault deposit. Depositing here is different from GNO validator staking.

The website's main actions are depositing and withdrawing, with an amount, selected asset, and receiver address. Connecting a wallet permits transaction requests; watching an address remains read-only. Native xDAI deposits do not require ERC-20 approval. WXDAI deposits and adapter withdrawals can need token/share approval. Approval authorizes spending and is distinct from depositing or withdrawing. Supported wallets may batch approval with the action; otherwise the user completes separate steps. The app also supports asset-amount withdrawals and share redemption, with Max redeeming all selected shares. Users should check amounts, network, receiver, and permissions before signing and keep native xDAI for gas.

Yield is variable. The app describes a Gnosis boost based on the relationship between the bridge's reported invested balance and the Gnosis vault's total assets. Its multiplier is not a guaranteed return or a constant. Cross-chain delivery, contract updates, and governance-set rates affect the savings mechanism. The guide explains these dependencies without publishing fixed live APY, TVL, or multiplier values.

The interest receiver spreads distribution of bridged earnings to the vault over three-day epochs; this is a distribution period, not a promise of a bridge arrival or a single payout every three days. The earning pace within an epoch implies APR, an annual rate before compounding. Earnings remain in the vault and increase the redeemable value of shares. The app converts this epoch-implied APR to yearly APY by compounding across 121 epochs per year, its approximation for three-day epochs: APY = (1 + r / 121)^121 - 1, where r is decimal APR. A steady 4% APR gives approximately 4.08% APY under this convention. Rates and bridge delivery can change; projected APY is not a promise of realized annual returns. For technical interpretation, vaultAPY() returns WAD-scaled (10^18) APR despite its name, and the rate query can remain cached for up to a day. Use the app for its displayed variable rate rather than assigning a current yield from this text.

Contract references below are on Gnosis, chain ID 100. Deployed bytecode and the vault's name, symbol, and WXDAI asset were checked at block 48,668,310. This check identifies the configured contracts; it is not a security audit. Sending tokens directly to a listed address is not equivalent to invoking a supported deposit operation.

- Savings xDAI ERC-4626 vault: 0xaf204776c7245bF4147c2612BF6e5972Ee483701.
- WXDAI underlying asset: 0xe91D153E0b41518A2Ce8Dd3D7944Fa863463a97d.
- Native-xDAI adapter/router: 0xD499b51fcFc66bd31248ef4b28d656d67E591A94.
- Bridge interest receiver: 0x670daeaF0F1a5e336090504C68179670B5059088.

Transactions require gas; external funding routes may have fees, slippage, and limits. Yield, stablecoin value, contract and upgrade behavior, bridge delivery, withdrawals, approvals, and receiver mistakes carry risks. The interface is not an insured bank account and does not promise profits, dollar redemption, or unrestricted withdrawal execution in every condition. It does not establish that another DeFi protocol currently accepts the shares. The ERC-4626 interface is a compatibility standard, not a safety certificate.

Gnosis bridges already integrate the Fast Confirmation Rule (FCR) for Ethereum-to-Gnosis transfers. Ethereum source blocks are usually fast-confirmed in about 12 seconds; this is not a guarantee that the full bridge transfer completes in 12 seconds. Gnosis-to-Ethereum transfers continue to use Gnosis finality, and Ethereum-origin transfers can fall back to finality during network instability or Ethereum upgrades. Users use the bridge as usual. FCR changes confirmation timing, not the savings rate; this app still links to external bridges rather than executing bridging in its deposit form.

The guide is the primary explanatory source for this website. Historical external documentation can contain old names and rate examples. Check current official bridge status and route information before relying on transfer timing.

## Site resources

- [Savings xDAI guide](https://sdai.gno.now/learn/): Assets, yield, sDAI/sUSDS terminology, APR/APY, workflows, ERC-4626, costs, risks, bridging, and verified configured contract references.
- [Savings xDAI app](https://sdai.gno.now/): Wallet interface for viewing the displayed variable rate and managing deposits and withdrawals on Gnosis.

## Optional

- [Gnosis xDAI bridge documentation](https://docs.gnosischain.com/bridges/About%20Token%20Bridges/xdai-bridge): Architecture and funding context; some savings examples are historical.
- [Gnosis bridge governance decisions](https://docs.gnosischain.com/bridges/management/decisions): Protocol upgrade context.
- [Sky's sUSDS explanation](https://sky.money/blog/what-is-susds): Ethereum USDS savings context, distinct from this Gnosis interface.
- [ERC-4626 standard](https://eips.ethereum.org/EIPS/eip-4626): Tokenized-vault assets, shares, and standard operations.
- [Gnosis FCR documentation](https://docs.gnosischain.com/bridges/fast-confirmation-rule): Integrated fast confirmation for Ethereum-origin transfers, direction-specific rules, and fallback behavior; confirmation time differs from total bridge time.