Example Usage

Learn how to interact with Sei precompiles using ethers.js to query and execute CosmWasm contracts from the EVM.

Under Proposal 115, no new CosmWasm contracts can be deployed on Sei. The examples below apply to pre-existing CosmWasm contracts only. Calls to instantiate() revert.

You can use the Sei precompiles like any standard smart contract on the EVM. For example, this page uses ethers.js to query an existing CosmWasm contract and execute actions on it.

Setup

To install ethers, run this command in a terminal in your project directory:

npm install ethers @sei-js/precompiles@^3

This example uses the CosmWasm precompile:

// Import Wasm precompile address and ABI
// View the source ABI: https://github.com/sei-protocol/sei-chain/tree/main/precompiles/wasmd
import { WASM_PRECOMPILE_ABI, WASM_PRECOMPILE_ADDRESS } from '@sei-js/precompiles';

Using the contract

Next, set up a provider and a contract to interact with Sei:

import { ethers, toUtf8Bytes, toUtf8String } from 'ethers';

// Using MetaMask as the signer and provider
const provider = new ethers.BrowserProvider(window.ethereum);
const signer = await provider.getSigner();

// Create a contract with the signer
const contract = new ethers.Contract(WASM_PRECOMPILE_ADDRESS, WASM_PRECOMPILE_ABI, signer);

Querying & executing a CosmWasm contract

When you have the contract instance, you can send query and execute messages to any CosmWasm smart contract. The example below assumes a counter contract with a get_count function.

// Replace with your contract
const COUNTER_CONTRACT_ADDRESS = 'sei1eyf...xff';

// Query to get the count on the counter contract (replace with function from your ABI)
const queryMsg = { get_count: {} };
const queryResponse = await contract.query(COUNTER_CONTRACT_ADDRESS, toUtf8Bytes(JSON.stringify(queryMsg)));
console.log(toUtf8String(queryResponse));

// Execute message to increment the count on the contract. (Replace with any function from your ABI)
// No funds are attached since the increment method does not require sei. (Your ABI may require funds)
const executeMsg = { increment: {} };
const executeResponse = await contract.execute(
  COUNTER_CONTRACT_ADDRESS,
  toUtf8Bytes(JSON.stringify(executeMsg)),
  toUtf8Bytes(JSON.stringify([])) // Used for sending funds if needed
);

// Wait for the transaction to be confirmed
await executeResponse.wait();
console.log(executeResponse);

Executing a payable function

This example executes the donate method on the same contract. It is similar to the increment method, but it also receives funds from the user and stores them in the contract.

// Execute a message to donate to the contract.
const executeMsg = { donate: {} };

// Funds are attached via overrides. This example is specific to ethers.js
const overrides = {
  value: ethers.parseEther('3.2') // Sending 3.2 sei
};
const executeResponse = await contract.execute(
  COUNTER_CONTRACT_ADDRESS,
  toUtf8Bytes(JSON.stringify(executeMsg)),
  toUtf8Bytes(JSON.stringify([])), // No Bank Module funds attached
  overrides
);

await executeResponse.wait();
const receipt = await provider.getTransactionReceipt(executeResponse.hash);

For payable contracts, attach native SEI through msg.value.