> ## Documentation Index
> Fetch the complete documentation index at: https://yieldxyz.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Concrete

> Supply USDT or frxUSD into Concrete ERC-4626 vaults on Ethereum and exit through a weekly epoch withdrawal queue.

Concrete runs curated, yield-bearing vaults on Ethereum. You deposit a single asset, receive an ERC-4626 vault share, and the share's value rises through `pricePerShare` as the vault's strategy earns. Deposits behave like a standard ERC-4626 vault; exits run through an epoch-based withdrawal queue instead of an instant redemption.

## Availability

| Network | Input token | Position token | Minimum deposit |
| - | - | - | - |
| Ethereum | USDT | ctDefiUSDT (Concrete Decentralized Finance USDT) | 1 USDT |
| Ethereum | frxUSD | ctfrxUSD+ (Concrete FraxUSD+) | None |

Query [`GET /v1/yields?providers=concrete`](/api-reference/YieldsController_getYields) for the vaults enabled for your project.

## Entering

Entering approves the input token (if needed) and deposits it; the vault mints shares immediately, subject to the vault's minimum deposit where one applies.

## Exiting

Exiting does not pay out in the same transaction. A `redeem` call moves your shares into the current weekly epoch instead of redeeming them, gated by the vault's per-epoch minimum and maximum withdrawal limits: a request below the minimum or above the per-epoch maximum is rejected, and a `useMaxAmount` exit is automatically capped to the per-epoch maximum.

Once the epoch is processed, your request becomes claimable. Submit the `CLAIM_UNSTAKED` pending action to call `claimWithdrawal`, which claims every processed epoch you hold in a single transaction and returns the underlying asset.

<Warning>
  Withdrawals are not instant. After a request, the position shows as an `exiting` balance (valued at the current share price) until its epoch processes, then as a `withdrawable` balance claimable through `CLAIM_UNSTAKED` (valued at the epoch's locked price). Epochs process on a roughly weekly cadence; the yield's `cooldownPeriod` metadata reports 7 days.
</Warning>

## Rewards and position

The vault share's value rises automatically as the underlying strategy earns; no claim step is needed for this base yield. Concrete vaults carry no separate reward token.

## List the live yields

Copy this request to list the Concrete yields enabled for your project. Yield IDs change as markets and networks are added, so query the API rather than hardcoding them.

```bash theme={null}
curl "https://api.yield.xyz/v1/yields?providers=concrete&limit=100" \
  -H "x-api-key: $YIELD_API_KEY"
```

## Next steps

<Columns cols={2}>
  <Card title="Vaults" icon="vault" href="/documentation/earn/defi/vaults/index">
    Compare Concrete against the other vault integrations.
  </Card>

  <Card title="Action lifecycle" icon="arrows-rotate" href="/documentation/earn/core-concepts/actions">
    Build the enter and exit flow, including the CLAIM\_UNSTAKED pending action.
  </Card>
</Columns>


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