Karma Wallet

Karma Wallet is an Account Abstraction (AA) smart wallet that automatically rounds up your gas fees and sends the spare change to a Tip Jar.

For example, if your transaction gas fee is $0.087, Karma Wallet will round it up to the nearest $0.01 and send the difference ($0.003) to the Tip Jar. This way, every transaction you make leaves behind a little karma for a cause you care about.

Powered by ERC-4337 smart accounts, Karma Wallet seamlessly integrates this tipping logic into your wallet’s transaction flow without requiring any additional user action.

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🎯 Motive

Gas fees are a necessary part of using the blockchain, but they’re often odd amounts that leave “dust” in the wallet. Karma Wallet turns these small amounts into meaningful contributions:

• Support open-source projects without actively thinking about it.
• Fund community initiatives in a passive, automated way.
• Gamify generosity by making every transaction part of a bigger giving story.

Instead of letting your micro-ETH fragments sit idle, they get converted into micro-donations.

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⚙️ How It Works — Detailed UserOperation Flow

Karma Wallet is built on ERC-4337 and works within the UserOperation lifecycle. Here’s the exact flow:

1️⃣ Transaction Initiation

• User interacts with a dApp via Karma Wallet.
• The wallet constructs a UserOperation with:
  • sender = Karma Wallet smart account address.
  • callData = Encoded function call to the target dApp contract.
  • value = Transaction value.
  • maxFeePerGas = Current gas settings.
  • maxPriorityFeePerGas = Current gas settings.
  • paymasterAndData = Empty bytes.
  • signature = Empty bytes.

2️⃣ UserOperation is signed and sent to Bundler

• The wallet sends the UserOperation to the Bundler.
• The Bundler processes the UserOperation and sends it to the EntryPoint.
• The EntryPoint processes the UserOperation and sends it to the Account Abstraction smart contract.

3️⃣ Account Abstraction Smart Contract

function execute(address dest, uint256 value, bytes calldata func) external {
    _requireFromEntryPointOrOwner();

    uint256 gasPre = gasleft();
    _call(dest, value, func);
    uint256 gasPost = gasleft();

    uint256 gasUsed = gasPre - gasPost;
    uint256 balance = address(this).balance;

    uint256 tip = _calculateTip(gasUsed);

    if (tip < balance) {
        _jar.deposit{value: tip}(gasUsed, tip);
    }
}

function _calculateTip(uint256 gasUsed) internal view returns (uint256) {
    uint256 ethPriceUSD = _oracleAdaptor.getLatestEthPriceInUsd();

    uint256 gasCostInWei = gasUsed * tx.gasprice;
    uint256 gasCostInUSD = (gasCostInWei * ethPriceUSD) / 1e18;

    uint256 tipInUSD = 0;
    uint256 roundingMultipleUSD = 1e16; // $0.01 in 18-decimal USD
    if (gasCostInUSD > 0) {
        uint256 remainder = gasCostInUSD % roundingMultipleUSD;
        if (remainder > 0) {
            tipInUSD = roundingMultipleUSD - remainder;
        }
    }

    uint256 tipInWei = (tipInUSD * 1e18) / ethPriceUSD;
    return tipInWei;
}

• The Account Abstraction smart contract processes the UserOperation and sends it to the EntryPoint.
• gasPre and gasPost measure the gas consumed during the call.
• _calculateTip(gasUsed) converts gas used into USD value and determines the rounded-up tip.
• If the wallet has enough ETH to cover the tip, it’s sent to the _jar contract.

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Screenshots 📸

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📍 Contract Addresses

Contract	Chain	Address
Karma Account Factory	Morph Holesky	0xe2567b2a7214877d395dfa6ca72335644b26dc23
Pyth Adaptor	Morph Holesky	0x2ca12ac2cb30b9acbdb6d9c7dcfc895338904a93

🛠 Self-Host Bundler Guide — Alto Bundler

1. Clone the Alto Bundler repository.

git clone https://github.com/pimlicolabs/alto.git

2. Install the dependencies.

cd alto
pnpm install

3. Create Config for Morph Holesky Testnet at alto-config.json.

{
    "entrypoints": "0x0000000071727De22E5E9d8BAf0edAc6f37da032", // v0.7 Entrypoint
    "executor-private-keys": "private-key",
    "utility-private-key": "private-key",
    "rpc-url": "https://rpc-quicknode-holesky.morphl2.io",
    "safe-mode": false,
    "port": 4337,
    "chain-type": "op-stack",
    "legacy-transactions": true
}

4. Update L1GasProxy Contract Address in src/utils/preVerificationGasCalulator.ts:L588:

const opGasPriceOracle = getContract({
    abi: OpL1FeeAbi,
-    address: "0x420000000000000000000000000000000000000F",
+    address: "0x530000000000000000000000000000000000000f",
    client: {
        public: publicClient
    }
})

5. Build the bundler.

pnpm build

6. Run the bundler.

./alto config="alto.config.json"

7. Start a local Proxy

npx local-cors-proxy --proxyUrl http://localhost:4337

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Get Started 🚀

The following repository is a turborepo and divided into the following:

• apps/web - The web application built using Vite.

First install the dependencies by running the following:

pnpm install && cd apps/web

Then fill in the Environment variables in apps/www/.env.local

VITE_REOWN_PROJECT_ID="reown-project-id"
VITE_BUNDLER_URL="http://localhost:8010/proxy"

Then run the following command to start the application:

pnpm dev

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🔮 Future - Modular Safe Account with Hooks

The current Karma Wallet is a modified SimpleSmartAccount, but future plans include:

• Migrating to Safe-based modular accounts.
• Using preExec and postExec hooks:
  • preExec: Estimate and lock in tip before execution.
  • postExec: Execute final tip transfer after actual gas cost known.
• Supporting multi-recipient tips (split between multiple causes).
• Integrating Paymaster sponsorship for gasless tip donations.

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📝 License

The Karma Wallet is licensed under the MIT License.

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