***
## Implementation Guide
Developers can integrate WHBAR into their applications by leveraging the following functions.
### Wrapping HBAR
To convert HBAR into its ERC20 representation (WHBAR), use the `deposit()` function. Keep in mind that:
* **Native HBAR:** Uses **8** decimal places (**tinybars**).
* **WHBAR (ERC20):** Uses **8** decimal places (**tinybars**) throughout — balances, transfers, `deposit()`, and `withdraw()`. `deposit()` simply mints an amount of WHBAR equal to the `msg.value` it receives, and `msg.value` is tinybar during EVM execution. The 18-decimal weibar form is **only** the transaction `value` an *off-chain* caller submits; the relay converts it to tinybar before `deposit()` runs.
How you specify the value depends on **who calls `deposit()`**:
* **From off-chain tooling (ethers/viem/wallet):** set the transaction `value` in **weibar** (10¹⁸ per HBAR). The relay converts it to tinybar, so sending `10 * 10**18` weibar wraps 10 HBAR → 10 WHBAR.
* **From another contract:** the `value` is **tinybar** (no conversion) — use `10 * 10**8` for 10 HBAR. Passing `10 * 10**18` here would send 10¹⁸ tinybar, which exceeds the total HBAR supply and reverts.
```solidity wrap theme={null}
/**
* @notice Wrap 10 HBAR into WHBAR from within a contract.
* @dev Contract-to-contract `value` is TINYBAR (8 decimals): 1 HBAR = 1e8.
*/
function wrapTenHbar() public {
whbarContract.deposit{value: 10 * 10**8}(); // 10 HBAR
}
```
### Unwrapping WHBAR
When you want to convert back to redeem WHBAR for native HBAR, call the `withdraw()` function with `amount` in **tinybars** (10⁸ per HBAR). The value in WHBAR is directly mapped back to HBAR with the same 8 decimal places:
```solidity wrap theme={null}
/**
* @notice Burns WHBAR tokens and returns the equivalent HBAR
* @param amount The amount of WHBAR to burn
*/
function withdraw(uint256 amount) public {
// To unwrap 5 WHBAR back to HBAR
whbarContract.withdraw(5 * 10**8);
}
```
This burns 5 WHBAR and sends back 5 HBAR to the wallet.
| Function | Description | Example |
|---|---|---|
transfer | Send WHBAR directly to another address | whbar.transfer(recipient, amount) |
approve | Authorize a third party to spend your WHBAR | whbar.approve(spender, amount) |
transferFrom | Transfer WHBAR as an authorized spender | whbar.transferFrom(owner, recipient, amount) |
balanceOf | Check WHBAR balance of an address | whbar.balanceOf(address) |
totalSupply | Get the total amount of WHBAR in circulation | whbar.totalSupply() |
| Network | Contract ID | EVM Address |
|---|---|---|
| ✅ Hedera Mainnet | 0.0.8840785 | 0xb1F616b8134F602c3Bb465fB5b5e6565cCAd37Ed |
| ✅ Hedera Testnet | 0.0.5816542 | 0xb1F616b8134F602c3Bb465fB5b5e6565cCAd37Ed |
| 🔜 Other Networks | Coming soon | Coming soon |