> For the complete documentation index, see [llms.txt](https://docs.somnia.network/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.somnia.network/developer/building-dapps/tokens-and-nfts/using-native-somi-stt.md). # Using Native Coin (SOMI/STT) SOMI is the native coin of the Somnia Network, similar to ETH on Ethereum. Unlike ERC20 tokens, SOMI is built into the protocol itself and does not have a contract address. {% hint style="warning" %} Kindly note that the Native Coin for Somnia Testnet is STT. {% endhint %} {% embed url="" %} This multi-part guide shows how to use SOMI for: * Payments * Escrow * Donations & Tipping * Sponsored gas via Account Abstraction ## Use SOMI for Payments in Smart Contracts A simple contract that accepts exact SOMI payments: ```solidity function payToAccess() external payable { require(msg.value == 0.01 ether, "Must send exactly 0.01 SOMI"); } ``` Use `msg.value` to access the native coin sent in a transaction. No ERC20 functions are needed. To withdraw collected SOMI: ```solidity function withdraw() external onlyOwner { payable(owner).transfer(address(this).balance); } ``` Deploy using Hardhat Ignition or Viem and test with a `sendTransaction` call.
Example.sol ```solidity // SPDX-License-Identifier: MIT pragma solidity ^0.8.20; contract SOMIPayment { address public owner; constructor() { owner = msg.sender; } // Modifier to restrict access to the contract owner modifier onlyOwner() { require(msg.sender == owner, "Only owner can call this"); _; } // User must send exactly 0.01 SOMI to access this feature function payToAccess() external payable { require(msg.value == 0.01 ether, "Must send exactly 0.01 SOMI"); // Logic for access: mint token, grant download, emit event, etc. } // Withdraw collected SOMI to owner function withdraw() external onlyOwner { payable(owner).transfer(address(this).balance); } } ```
## Build an SOMI Escrow Contract A secure escrow contract allows a buyer to deposit SOMI and later release or refund: ```solidity constructor(address payable _seller) payable { buyer = msg.sender; seller = _seller; amount = msg.value; } ``` Release funds to the seller: ```solidity function release() external onlyBuyer { seller.transfer(amount); } ``` Deploy with Hardhat Ignition and pass SOMI as `value` during deployment.
Example.sol ```solidity // SPDX-License-Identifier: MIT pragma solidity ^0.8.20; contract SOMIEscrow { address public buyer; address payable public seller; uint256 public amount; bool public isDeposited; constructor(address payable _seller) payable { buyer = msg.sender; seller = _seller; amount = msg.value; require(amount > 0, "Must deposit SOMI"); isDeposited = true; } modifier onlyBuyer() { require(msg.sender == buyer, "Only buyer can call this"); _; } function release() external onlyBuyer { require(isDeposited, "No funds to release"); isDeposited = false; seller.transfer(amount); } function refund() external onlyBuyer { require(isDeposited, "No funds to refund"); isDeposited = false; payable(buyer).transfer(amount); } } ```
## SOMI Tip Jar Allow any wallet to send tips directly: ```solidity receive() external payable { emit Tipped(msg.sender, msg.value); } ``` Withdraw all tips: ```solidity function withdraw() external onlyOwner { payable(owner).transfer(address(this).balance); } ```
Example.sol ```solidity // SPDX-License-Identifier: MIT pragma solidity ^0.8.20; contract SOMITipJar { address public owner; event Tipped(address indexed from, uint256 amount); event Withdrawn(address indexed to, uint256 amount); constructor() { owner = msg.sender; } receive() external payable { emit Tipped(msg.sender, msg.value); } function withdraw() external { require(msg.sender == owner, "Only owner can withdraw"); uint256 balance = address(this).balance; require(balance > 0, "No tips available"); payable(owner).transfer(balance); emit Withdrawn(owner, balance); } } ```
## Frontend tip ```typescript await walletClient.sendTransaction({ to: '0xTipJarAddress', value: parseEther('0.05'), }); ``` ## Sponsor SOMI Transactions with Account Abstraction Using a smart account + relayer (e.g. via Privy, Thirdweb), the dApp can cover gas fees: ```typescript await sendTransaction({ to: contractAddress, data: mintFunctionEncoded, value: 0n, // user sends no SOMI }); ``` The Smart Contract function can execute mint or other logic as usual. The paymaster or relayer pays SOMI. ## Conclusion * **SOMI is native** and used via `msg.value`, `.transfer()`, and `payable`. * **There is no contract address for SOMI (STT for Testnet)**. * You can integrate SOMI into any Solidity or Viem app with no ERC20 logic. * Account Abstraction enables gasless dApps using SOMI as sponsor currency.
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