v1 Generate Payloads: DeFi Transaction Calldata

The v1 payload generation endpoints prepare transaction details and calldata for interactions with smart contracts across leading DeFi protocols, including Aave, Morpho, Euler, Compound, Maker/Sky, and Lido. The API is entirely non-custodial — it constructs payloads for you to submit, without ever holding or controlling user funds.

These are legacy v1 endpoints. They are fully supported and maintained. For new integrations, consider using the v2 endpoints.

Get supported vaults

GET https://api.vaults.fyi/v1/transactions/vaults

Returns the list of vaults that support transactional endpoints on a given network. Each entry includes the vault name, protocol, contract address, LP token address, and supported assets. Authentication: x-api-key header required.

Query parameters

network

string

required

Network name or CAIP identifier. Possible values: mainnet, arbitrum, optimism, polygon, base, gnosis, unichain.

Example request

GET /v1/transactions/vaults?network=mainnet HTTP/1.1
Host: api.vaults.fyi
x-api-key: YOUR_API_KEY
Accept: */*

Example response

[
  {
    "name": "USDC Lending",
    "protocol": "Aave",
    "address": "0xdef...456",
    "lpTokenAddress": "0xghi...789",
    "network": "mainnet",
    "assets": [
      {
        "address": "0xa0b...789",
        "name": "USD Coin",
        "symbol": "USDC",
        "decimals": 6,
        "network": "mainnet"
      }
    ]
  }
]

Get supported assets

GET https://api.vaults.fyi/v1/transactions/assets

Returns all assets that can be used with transactional endpoints on a given network. Authentication: x-api-key header required.

Query parameters

network

string

required

Network name or CAIP identifier. Possible values: mainnet, arbitrum, optimism, polygon, base, gnosis, unichain.

Example request

GET /v1/transactions/assets?network=mainnet HTTP/1.1
Host: api.vaults.fyi
x-api-key: YOUR_API_KEY
Accept: */*

Example response

[
  {
    "address": "0xa0b...789",
    "name": "USD Coin",
    "symbol": "USDC",
    "decimals": 6,
    "network": "mainnet"
  }
]

Get contract interaction details

GET https://api.vaults.fyi/v1/transactions/vaults/actions/details

Returns the available smart contract interactions for a specific vault and user, including the current deposit and redeem steps, LP token balance, idle assets, locked value, unclaimed assets, and any claimable rewards. Use this endpoint to determine which actions are available before preparing calldata. Authentication: x-api-key header required.

Query parameters

network

string

required

Network name or CAIP identifier.

userAddress

string

required

User wallet address. Pattern: ^0x[a-fA-F0-9]{40}$.

vaultAddress

string

required

Vault contract address. Pattern: ^0x[a-fA-F0-9]{40}$.

Example request

GET /v1/transactions/vaults/actions/details?network=mainnet&userAddress=0xabc...123&vaultAddress=0xdef...456 HTTP/1.1
Host: api.vaults.fyi
x-api-key: YOUR_API_KEY
Accept: */*

Example response

{
  "currentDepositStep": "deposit",
  "depositSteps": [
    {
      "actions": ["approve", "deposit"],
      "actionsUrl": "https://example.com/actions",
      "name": "deposit"
    }
  ],
  "currentRedeemStep": "redeem",
  "redeemSteps": [
    {
      "actions": ["redeem"],
      "actionsUrl": "https://example.com/actions",
      "name": "redeem"
    }
  ],
  "lpTokenBalance": "1045.123456",
  "idleAssets": { "USDC": "500.000000" },
  "lockedValueInAssets": { "USDC": "1050.000000" },
  "unclaimedAssets": { "USDC": "2.500000" },
  "rewards": {
    "claimable": [
      {
        "amount": "10.000000",
        "token": {
          "address": "0xjkl...012",
          "name": "Aave Token",
          "symbol": "AAVE",
          "decimals": 18,
          "network": "mainnet"
        }
      }
    ],
    "currentStep": "claim",
    "steps": [
      {
        "actions": ["claim"],
        "actionsUrl": "https://example.com/actions",
        "name": "claim"
      }
    ]
  }
}

Prepare supply / deposit calldata

GET https://api.vaults.fyi/v1/transactions/vaults/deposit

Returns the transaction payload and calldata needed to deposit assets into a vault. You can optionally request a simulation of the transaction before submitting it. Authentication: x-api-key header required.

Query parameters

network

string

required

Network name or CAIP identifier.

sender

string

required

Depositing wallet address. Pattern: ^0x[a-fA-F0-9]{40}$.

assetAddress

string

required

Token contract address to deposit. Pattern: ^0x[a-fA-F0-9]{40}$.

vaultAddress

string

required

Target vault address. Pattern: ^0x[a-fA-F0-9]{40}$.

amount

string

required

Amount to deposit, in the token’s smallest unit (e.g. wei for 18-decimal tokens).

simulate

string

default:"false"

Set to true to include a transaction simulation in the response.

Example request

GET /v1/transactions/vaults/deposit?network=mainnet&sender=0xabc...123&assetAddress=0xa0b...789&vaultAddress=0xdef...456&amount=1000000000 HTTP/1.1
Host: api.vaults.fyi
x-api-key: YOUR_API_KEY
Accept: */*

Example response

{
  "currentActionIndex": 1,
  "actions": [
    {
      "name": "deposit",
      "tx": {
        "to": "0xdef...456",
        "chainId": 1,
        "data": "0x...",
        "value": "0"
      },
      "simulation": {
        "url": "https://example.com/sim/abc",
        "status": "success",
        "tokensReceived": { "aUSDC": "1000000000" },
        "tokensSpent": { "USDC": "1000000000" }
      }
    }
  ]
}

Prepare withdraw / redeem calldata

GET https://api.vaults.fyi/v1/transactions/vaults/redeem

Returns the transaction payload and calldata needed to withdraw assets from a vault.

For vaults with redemption queues or waiting periods (e.g. Lido stETH), use the Request Redeem and Claim Redeem endpoints below instead.

Authentication: x-api-key header required.

Query parameters

network

string

required

Network name or CAIP identifier.

sender

string

required

Withdrawing wallet address. Pattern: ^0x[a-fA-F0-9]{40}$.

assetAddress

string

required

Token contract address to receive. Pattern: ^0x[a-fA-F0-9]{40}$.

vaultAddress

string

required

Vault address to redeem from. Pattern: ^0x[a-fA-F0-9]{40}$.

amount

string

required

Amount to redeem, in the token’s smallest unit.

all

string

Set to true to redeem the full position.

simulate

string

default:"false"

Set to true to include a transaction simulation in the response.

Example request

GET /v1/transactions/vaults/redeem?network=mainnet&sender=0xabc...123&assetAddress=0xa0b...789&vaultAddress=0xdef...456&amount=1000000000 HTTP/1.1
Host: api.vaults.fyi
x-api-key: YOUR_API_KEY
Accept: */*

Prepare request-redeem calldata

GET https://api.vaults.fyi/v1/transactions/vaults/request-redeem

Initiates a redemption request for vaults that have a waiting period before assets can be claimed (e.g. Lido stETH). Submit this transaction first, then use the claim-redeem endpoint once the redemption is ready. Authentication: x-api-key header required.

Query parameters

network

string

required

Network name or CAIP identifier.

sender

string

required

Wallet address submitting the request. Pattern: ^0x[a-fA-F0-9]{40}$.

assetAddress

string

required

Token contract address. Pattern: ^0x[a-fA-F0-9]{40}$.

vaultAddress

string

required

Vault address. Pattern: ^0x[a-fA-F0-9]{40}$.

amount

string

required

Amount to request, in the token’s smallest unit.

simulate

string

default:"false"

Set to true to include a transaction simulation in the response.

Example request

GET /v1/transactions/vaults/request-redeem?network=mainnet&sender=0xabc...123&assetAddress=0xa0b...789&vaultAddress=0xdef...456&amount=1000000000000000000 HTTP/1.1
Host: api.vaults.fyi
x-api-key: YOUR_API_KEY
Accept: */*

Prepare claim-redeem calldata

GET https://api.vaults.fyi/v1/transactions/vaults/claim-redeem

Claims assets after a redemption request has been fulfilled. Use this after calling request-redeem and waiting for the vault’s redemption period to complete. Authentication: x-api-key header required.

Query parameters

network

string

required

Network name or CAIP identifier.

sender

string

required

Wallet address claiming the assets. Pattern: ^0x[a-fA-F0-9]{40}$.

assetAddress

string

required

Token contract address. Pattern: ^0x[a-fA-F0-9]{40}$.

vaultAddress

string

required

Vault address. Pattern: ^0x[a-fA-F0-9]{40}$.

simulate

string

default:"false"

Set to true to include a transaction simulation in the response.

Example request

GET /v1/transactions/vaults/claim-redeem?network=mainnet&sender=0xabc...123&assetAddress=0xa0b...789&vaultAddress=0xdef...456 HTTP/1.1
Host: api.vaults.fyi
x-api-key: YOUR_API_KEY
Accept: */*

Prepare claim-rewards calldata

GET https://api.vaults.fyi/v1/transactions/vaults/claim-rewards

Returns the transaction payload and calldata needed to claim accrued rewards for a user’s position in a specific vault. Authentication: x-api-key header required.

Query parameters

network

string

required

Network name or CAIP identifier.

sender

string

required

Wallet address claiming rewards. Pattern: ^0x[a-fA-F0-9]{40}$.

assetAddress

string

required

Token contract address. Pattern: ^0x[a-fA-F0-9]{40}$.

vaultAddress

string

required

Vault address. Pattern: ^0x[a-fA-F0-9]{40}$.

simulate

string

default:"false"

Set to true to include a transaction simulation in the response.

Example request

GET /v1/transactions/vaults/claim-rewards?network=mainnet&sender=0xabc...123&assetAddress=0xa0b...789&vaultAddress=0xdef...456 HTTP/1.1
Host: api.vaults.fyi
x-api-key: YOUR_API_KEY
Accept: */*

Example response (all calldata endpoints)

{
  "currentActionIndex": 1,
  "actions": [
    {
      "name": "claim-rewards",
      "tx": {
        "to": "0xdef...456",
        "chainId": 1,
        "data": "0x...",
        "value": "0"
      },
      "simulation": {
        "url": "https://example.com/sim/xyz",
        "status": "success",
        "tokensReceived": { "AAVE": "10000000000000000000" },
        "tokensSpent": {}
      }
    }
  ]
}

Sections

Endpoints

Beta

Alpha

v1 Generate Payloads: DeFi Transaction Calldata

Get supported vaults

Query parameters

Example request

Example response

Get supported assets

Query parameters

Example request

Example response

Get contract interaction details

Query parameters

Example request

Example response

Prepare supply / deposit calldata

Query parameters

Example request

Example response

Prepare withdraw / redeem calldata

Query parameters

Example request

Prepare request-redeem calldata

Query parameters

Example request

Prepare claim-redeem calldata

Query parameters

Example request

Prepare claim-rewards calldata

Query parameters

Example request

Example response (all calldata endpoints)

​Get supported vaults

​Query parameters

​Example request

​Example response

​Get supported assets

​Query parameters

​Example request

​Example response

​Get contract interaction details

​Query parameters

​Example request

​Example response

​Prepare supply / deposit calldata

​Query parameters

​Example request

​Example response

​Prepare withdraw / redeem calldata

​Query parameters

​Example request

​Prepare request-redeem calldata

​Query parameters

​Example request

​Prepare claim-redeem calldata

​Query parameters

​Example request

​Prepare claim-rewards calldata

​Query parameters

​Example request

​Example response (all calldata endpoints)

Get supported vaults

Query parameters

Example request

Example response

Get supported assets

Query parameters

Example request

Example response

Get contract interaction details

Query parameters

Example request

Example response

Prepare supply / deposit calldata

Query parameters

Example request

Example response

Prepare withdraw / redeem calldata

Query parameters

Example request

Prepare request-redeem calldata

Query parameters

Example request

Prepare claim-redeem calldata

Query parameters

Example request

Prepare claim-rewards calldata

Query parameters

Example request

Example response (all calldata endpoints)