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

# Vaults & deposits

> DEXVaults, collateral, and approval requirements for trading.

## Overview

Before placing orders, you must deposit tokens into **vaults**—ERC4626 vaults that hold your collateral for trading. Each tradeable token has its own vault:

* USDC → USDC vault
* MirrorToken → MirrorToken vault

Your tokens stay in these vaults while you trade. When you place orders, the required collateral is locked; when you cancel or claim, it's unlocked.

## Approval requirements

To trade, you need approvals on **both tokens and vaults**:

### For deposits

Approve the **Controller** on each **token**:

```solidity theme={null}
USDC.approve(CONTROLLER, amount);
mirrorToken.approve(CONTROLLER, amount);
```

This allows the Controller to transfer tokens from your wallet into vaults.

### For trading

Approve the **BookManager** on each **vault**:

```solidity theme={null}
vaultUSDC.approve(BOOK_MANAGER, type(uint256).max);
vaultMirrorToken.approve(BOOK_MANAGER, type(uint256).max);
```

This allows the BookManager to lock/unlock your collateral and settle trades.

## Required approvals checklist

Before trading a pair (e.g., USDC/MirrorToken), set up these approvals:

### 1. For USDC (quote currency)

* ✅ Approve **Controller** on **USDC token** (for deposits)
* ✅ Approve **BookManager** on **USDC vault** (for withdrawals and settlements)

### 2. For MirrorToken (base currency)

* ✅ Approve **Controller** on **MirrorToken** (for deposits)
* ✅ Approve **BookManager** on **MirrorToken vault** (for withdrawals and settlements)

### 3. Deposit funds

* ✅ Deposit USDC into its vault via `Controller.depositToVault(USDC, amount)`
* ✅ Deposit MirrorToken into its vault via `Controller.depositToVault(MirrorToken, amount)`

Once these steps are complete, you can:

* Place limit orders (make)
* Execute market orders (take)
* Cancel orders
* Claim proceeds

## Vault balances

Check your balances:

* `maxWithdraw(user)`: available to withdraw (excludes locked collateral)
* `lockedBalances(user)`: amount locked in open orders

**Important**: You cannot withdraw locked collateral—cancel your orders first.

## Basic operations

### Deposit

```solidity theme={null}
Controller.depositToVault(currency, amount);
```

### Withdraw

```solidity theme={null}
Controller.withdrawFromVault(currency, amount);
```

### Check balance

```solidity theme={null}
uint256 available = vault.maxWithdraw(user);    // Available to withdraw
uint256 locked = vault.lockedBalances(user);    // Locked in orders
```

## Example: full setup flow

```solidity theme={null}
// 1. Approve tokens for deposits
USDC.approve(CONTROLLER, 1000e6);           // 1000 USDC
mirrorToken.approve(CONTROLLER, 100e18);    // 100 tokens

// 2. Deposit into vaults
Controller.depositToVault(Currency.wrap(address(USDC)), 1000e6);
Controller.depositToVault(Currency.wrap(address(mirrorToken)), 100e18);

// 3. Approve vaults for trading
vaultUSDC.approve(BOOK_MANAGER, type(uint256).max);
vaultMirrorToken.approve(BOOK_MANAGER, type(uint256).max);

// Now ready to trade!
```

## Security

* Approvals are persistent—set once and forget
* Your tokens never leave the vaults during trading
* Locked collateral cannot be withdrawn, even with approvals

## See also

* [Controller](/mms-api/concepts/controller) - user-facing trading interface
* [Deposit & withdraw guide](/mms-api/guides/deposit-withdraw) - step-by-step instructions
* [Addresses](/mms-api/reference/addresses) - deployed contract addresses