> ## Documentation Index > Fetch the complete documentation index at: https://docs.tenderly.co/llms.txt > Use this file to discover all available pages before exploring further. # Solidity Cheatcodes > IVnetPrecompile interface reference for the Solidity-level cheatcodes available on every Virtual Environment at 0xc100000000000000000000000000000000000000. Every Virtual Environment exposes a precompile contract at `0xc100000000000000000000000000000000000000`. Calling functions on this precompile from inside a transaction lets your contracts manipulate on-chain state directly, storage slots, ETH balances, ERC-20 token balances, nonces, and event logs, without impersonating accounts or deploying helper proxies. These cheatcodes complement the [Admin RPC methods](/virtual-environments/admin-rpc). The Admin RPC methods manipulate state from outside a transaction (via JSON-RPC). The precompile manipulates state from inside a transaction (via Solidity call). Use the precompile when your setup needs to stay atomic, be replayable from a tx hash, or run in a loop over many slots. ## Interface Add this file to your project as `IVnetPrecompile.sol`: ```solidity title="IVnetPrecompile.sol" theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}} // SPDX-License-Identifier: MIT pragma solidity ^0.8.0; interface IVnetPrecompile { function setStorageAt(address target, bytes32 slot, bytes32 value) external returns (bool); function setBalance(address[] calldata addresses, uint256 balance) external returns (bool); function getStorageAt(address target, bytes32 slot) external view returns (bytes32); function addBalance(address[] calldata addresses, uint256 amount) external returns (bool); function setNonce(address target, uint256 value) external returns (bool); function setErc20Balance(address target, address[] calldata addresses, uint256 amount) external returns (bool); function addErc20Balance(address target, address[] calldata addresses, uint256 amount) external returns (bool); function setMaxErc20Balance(address target, address account) external returns (bool); function emitEvent(address target, bytes calldata data) external returns (bool); function emitEvent(address target, bytes32 topic1) external returns (bool); function emitEvent(address target, bytes32 topic1, bytes calldata data) external returns (bool); function emitEvent(address target, bytes32 topic1, bytes32 topic2) external returns (bool); function emitEvent(address target, bytes32 topic1, bytes32 topic2, bytes calldata data) external returns (bool); function emitEvent(address target, bytes32 topic1, bytes32 topic2, bytes32 topic3) external returns (bool); function emitEvent(address target, bytes32 topic1, bytes32 topic2, bytes32 topic3, bytes calldata data) external returns (bool); function emitEvent(address target, bytes32 topic1, bytes32 topic2, bytes32 topic3, bytes32 topic4) external returns (bool); function emitEvent(address target, bytes32 topic1, bytes32 topic2, bytes32 topic3, bytes32 topic4, bytes calldata data) external returns (bool); event SetStorageAtEvent(address target, bytes32 slot, bytes32 value); event SetBalanceEvent(address[] addresses, uint256 balance); event AddBalanceEvent(address[] addresses, uint256 amount); event SetNonceEvent(address target, uint256 value); event SetErc20BalanceEvent(address target, address[] addresses, uint256 amount); event AddErc20BalanceEvent(address target, address[] addresses, uint256 amount); event SetMaxErc20BalanceEvent(address target, address account); } ``` Reference it in your contract at the fixed address: ```solidity theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}} IVnetPrecompile constant VNET = IVnetPrecompile(0xc100000000000000000000000000000000000000); ``` ## Functions ### Storage | Function | Parameters | Returns | Description | | -------------- | ------------------------------------------------- | --------- | ---------------------------------------------- | | `setStorageAt` | `address target`, `bytes32 slot`, `bytes32 value` | `bool` | Writes `value` to `slot` on `target`. | | `getStorageAt` | `address target`, `bytes32 slot` | `bytes32` | Reads the current value of `slot` on `target`. | ```solidity theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}} VNET.setStorageAt(tokenContract, balanceSlot, bytes32(uint256(1000e18))); bytes32 val = VNET.getStorageAt(tokenContract, balanceSlot); ``` ### Balance | Function | Parameters | Returns | Description | | ------------ | ---------------------------------------- | ------- | ------------------------------------------------------------------------- | | `setBalance` | `address[] addresses`, `uint256 balance` | `bool` | Sets the ETH balance of every address in `addresses` to an exact value. | | `addBalance` | `address[] addresses`, `uint256 amount` | `bool` | Adds `amount` to the current ETH balance of every address in `addresses`. | ```solidity theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}} address[] memory accounts = new address[](2); accounts[0] = alice; accounts[1] = bob; VNET.setBalance(accounts, 10 ether); VNET.addBalance(accounts, 2 ether); ``` ### ERC-20 balances | Function | Parameters | Returns | Description | | -------------------- | --------------------------------------------------------- | ------- | --------------------------------------------------------------------------------------------- | | `setErc20Balance` | `address target`, `address[] addresses`, `uint256 amount` | `bool` | Sets the balance of every address in `addresses` to `amount` on the ERC-20 token at `target`. | | `addErc20Balance` | `address target`, `address[] addresses`, `uint256 amount` | `bool` | Adds `amount` to the current token balance of every address in `addresses`. | | `setMaxErc20Balance` | `address target`, `address account` | `bool` | Sets the token balance of `account` to the maximum value (`2^256 - 1`). | The precompile locates the token's balance storage slot automatically, so no slot input is required. Standard mapping layouts resolve directly and are cached after the first holder; non-standard layouts are discovered by probing the token's `balanceOf` execution. ```solidity theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}} address[] memory holders = new address[](2); holders[0] = alice; holders[1] = bob; VNET.setErc20Balance(USDC, holders, 1_000_000e6); VNET.addErc20Balance(USDC, holders, 500e6); VNET.setMaxErc20Balance(USDC, alice); ``` Tokens that pack extra flags into the balance storage slot report `balanceOf` accordingly. For example, USDC reserves the top bit of the slot, so after `setMaxErc20Balance` its `balanceOf` returns `2^255 - 1`. ### Nonce | Function | Parameters | Returns | Description | | ---------- | --------------------------------- | ------- | --------------------------------------- | | `setNonce` | `address target`, `uint256 value` | `bool` | Sets the transaction count of `target`. | ```solidity theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}} VNET.setNonce(account, 42); ``` ### Events `emitEvent` fires a log whose `address` field is `target`, not the calling contract. Downstream consumers (indexers, subgraphs, webhooks) treat the log as a real emission from `target`. Nine overloads cover zero to four indexed topics with an optional unindexed data payload: | Overload | Topics | Data | | ----------------------------------------- | ------ | ---- | | `emitEvent(target, data)` | 0 | ✓ | | `emitEvent(target, t1)` | 1 | , | | `emitEvent(target, t1, data)` | 1 | ✓ | | `emitEvent(target, t1, t2)` | 2 | , | | `emitEvent(target, t1, t2, data)` | 2 | ✓ | | `emitEvent(target, t1, t2, t3)` | 3 | , | | `emitEvent(target, t1, t2, t3, data)` | 3 | ✓ | | `emitEvent(target, t1, t2, t3, t4)` | 4 | , | | `emitEvent(target, t1, t2, t3, t4, data)` | 4 | ✓ | `topic1` is typically `keccak256("EventName(type,type,...)")`. Example, spoof a USDC `Transfer`: ```solidity theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}} VNET.emitEvent( USDC, keccak256("Transfer(address,address,uint256)"), bytes32(uint256(uint160(from))), bytes32(uint256(uint160(to))), abi.encode(amount) ); ``` ### Cheatcode events Every state-changing cheatcode emits a corresponding event from the precompile address (`0xc100000000000000000000000000000000000000`): | Cheatcode | Event | | -------------------- | --------------------------------------------------------------------------- | | `setStorageAt` | `SetStorageAtEvent(address target, bytes32 slot, bytes32 value)` | | `setBalance` | `SetBalanceEvent(address[] addresses, uint256 balance)` | | `addBalance` | `AddBalanceEvent(address[] addresses, uint256 amount)` | | `setNonce` | `SetNonceEvent(address target, uint256 value)` | | `setErc20Balance` | `SetErc20BalanceEvent(address target, address[] addresses, uint256 amount)` | | `addErc20Balance` | `AddErc20BalanceEvent(address target, address[] addresses, uint256 amount)` | | `setMaxErc20Balance` | `SetMaxErc20BalanceEvent(address target, address account)` | When inspecting a receipt for a log spoofed via `emitEvent`, filter `logs[]` by the target address to ignore the precompile's own entries. ## Known limitations * **Base-based Virtual Environments.** Solidity cheatcodes are not available on Base. * **Arbitrum-based Virtual Environments.** Cheatcode calls made through `eth_call` do not work due to Arbitrum internals. Transactions, gas estimates, and simulations work as expected. ## See also * [Admin RPC](/virtual-environments/admin-rpc), the equivalent JSON-RPC methods for state manipulation from outside a transaction. * [Foundry cheatcode tutorial](/virtual-environments/develop/solidity-cheatcodes), end-to-end walkthrough deploying a reusable cheatcode playground.