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.

Kindly note that the Native Coin for Somnia Testnet is STT.

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:

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:

function withdraw() external onlyOwner {
  payable(owner).transfer(address(this).balance);
}

Deploy using Hardhat Ignition or Viem and test with a sendTransaction call.

Example.sol

// 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:

constructor(address payable _seller) payable {
  buyer = msg.sender;
  seller = _seller;
  amount = msg.value;
}

Release funds to the seller:

function release() external onlyBuyer {
  seller.transfer(amount);
}

Deploy with Hardhat Ignition and pass SOMI as value during deployment.

Example.sol

// 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:

receive() external payable {
  emit Tipped(msg.sender, msg.value);
}

Withdraw all tips:

function withdraw() external onlyOwner {
  payable(owner).transfer(address(this).balance);
}

Example.sol

// 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

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:

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.