> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mls.onchainden.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Depositing into DeFi

> Submit a vault deposit transaction with the SDK.

## What is a vault deposit transaction?

A vault deposit transaction sends assets into a DeFi vault (often ERC-4626) and
receives vault shares in return. This example uses an ERC-4626 vault deposit.
Adjust the contract address, function signature, and amount for your protocol.

## 1) Set up the client and signer

Create the SDK client and signer used for approvals.

```typescript theme={null}
import { DenClient } from "@onchainden/mls-sdk-ts";
import { privateKeyToAccount } from "viem/accounts";
import { encodeAbiParameters, encodeFunctionData, type Hex } from "viem";

const signer = privateKeyToAccount("0xYOUR_PRIVATE_KEY");

const client = new DenClient({
  apiKey: process.env.DEN_API_KEY!,
  baseUrl: process.env.DEN_API_BASE_URL!,
});
```

## 2) Encode the vault deposit

Encode the ERC-4626 deposit call data for the vault.

```typescript theme={null}
const erc4626DepositAbi = [
  {
    name: "deposit",
    type: "function",
    stateMutability: "nonpayable",
    inputs: [
      { name: "assets", type: "uint256" },
      { name: "receiver", type: "address" },
    ],
    outputs: [{ name: "shares", type: "uint256" }],
  },
];

const callData = encodeFunctionData({
  abi: erc4626DepositAbi,
  functionName: "deposit",
  args: [1_000_000_000n, "0xReceiver..."],
});
```

## 3) Create the deposit transaction

Create a transaction proposal with the encoded deposit data.

```typescript theme={null}
const { data: queued } = await client.createTransaction({
  accountId: "acc_123",
  initiatorWalletAddress: signer.address,
  networkId: 1,
  policyId: "pol_123",
  description: "Deposit into vault",
  to: "0xVaultAddress...",
  value: "0",
  data: callData,
});
```

## 4) Sign and execute

Sign the initiator payload hash, submit the encoded signature, then execute once approvals are ready.

```typescript theme={null}
const initiatorSig = encodeAbiParameters(
  [
    { type: "address", name: "address" },
    { type: "bytes", name: "signature" },
  ],
  [
    signer.address,
    await signer.sign({
      hash: queued.signatureData.initiatorPayload as Hex,
    }),
  ]
);

const { data: afterInitiator } = await client.signTransaction(queued.id, {
  type: "initiator",
  signature: initiatorSig,
});

if (afterInitiator.signatureData.status === "approvalReady") {
  await client.executeTransaction(queued.id, { type: "approve" });
}
```

## Full example

```typescript theme={null}
import { DenClient } from "@onchainden/mls-sdk-ts";
import { privateKeyToAccount } from "viem/accounts";
import { encodeFunctionData } from "viem";

// 1) Set up the client and signer.
const signer = privateKeyToAccount("0xYOUR_PRIVATE_KEY");

const client = new DenClient({
  apiKey: process.env.DEN_API_KEY!,
  baseUrl: process.env.DEN_API_BASE_URL!,
});

// 2) Encode the vault deposit.
const erc4626DepositAbi = [
  {
    name: "deposit",
    type: "function",
    stateMutability: "nonpayable",
    inputs: [
      { name: "assets", type: "uint256" },
      { name: "receiver", type: "address" },
    ],
    outputs: [{ name: "shares", type: "uint256" }],
  },
];

const callData = encodeFunctionData({
  abi: erc4626DepositAbi,
  functionName: "deposit",
  args: [1_000_000_000n, "0xReceiver..."],
});

// 3) Create the deposit transaction.
const { data: queued } = await client.createTransaction({
  accountId: "acc_123",
  initiatorWalletAddress: signer.address,
  networkId: 1,
  policyId: "pol_123",
  description: "Deposit into vault",
  to: "0xVaultAddress...",
  value: "0",
  data: callData,
});

// 4) Sign and execute.
const initiatorSig = encodeAbiParameters(
  [
    { type: "address", name: "address" },
    { type: "bytes", name: "signature" },
  ],
  [
    signer.address,
    await signer.sign({
      hash: queued.signatureData.initiatorPayload as Hex,
    }),
  ]
);

const { data: afterInitiator } = await client.signTransaction(queued.id, {
  type: "initiator",
  signature: initiatorSig,
});

if (afterInitiator.signatureData.status === "approvalReady") {
  await client.executeTransaction(queued.id, { type: "approve" });
}
```