Sign a Smart Contract Call with Axiome Connect

Axiome Connect allows you to securely sign smart contract calls from external applications using either an authorization code or a QR code.

This is useful for integrating web apps, bots, or scripts with your wallet in a secure and interactive way.

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Step 1: Prepare the JSON Payload

Create a JSON object describing the smart contract call you want to sign. Here's an example for a token swap:

{
  "type": "cosmwasm_execute",
  "network": "axiome-devnet",
  "contract_addr": "axm14hj2tavq8fpesdwxxcu44rty3hh90vhujrvcmstl4zr3txmfvw9sletw5k",
  "funds": [
    {
      "denom": "uaxm",
      "amount": "1000000"
    }
  ],
  "msg": {
    "swap": {
      "input_token": "Token1",
      "input_amount": "1000000",
      "min_output": "800000"
    }
  },
  "memo": "test memo"
}

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Step 2: Encode to Base64 and Prefix

Encode the JSON as a Base64 string (without line breaks or padding), then prefix it with axiomesign://.

Example in JavaScript:

const payload = { /* your JSON here */ };
const base64 = Buffer.from(JSON.stringify(payload)).toString('base64');
const finalString = `axiomesign://${base64}`;
console.log(finalString);

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Step 3: Use Axiome Connect

You have two options to sign the transaction:

Option 1: Paste the string

Paste the axiomesign://... string into the input field of Axiome Connect in your Axiome Wallet app (starting from version 2.1.12 in iOS and 2.0.56 in Android)

Press Connect — your app will decode the payload and ask you to sign the transaction.

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Option 2: Scan a QR Code

You can also encode the axiomesign://... string into a QR code and scan it directly from the Axiome Connect mobile app.

You can use any QR generator — just make sure the encoded string starts with axiomesign:// and contains the full base64-encoded payload.

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Notes

• contract_addr must be a valid CosmWasm contract address on the selected network.

• funds is optional if the contract call doesn’t require tokens.

• memo is optional and can be used for tagging or tracking.

• The app will preview the decoded message before signing.