> ## Documentation Index
> Fetch the complete documentation index at: https://docs.theblockchainlibrary.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Read Contract Events with ethers.js

> Listen to and query historical smart contract events using ethers.js.

# Read Contract Events with ethers.js

Listen to and query historical smart contract events using ethers.js.

Listen to and query historical smart contract events using ethers.js.

## Explanation

queryFilter retrieves historical events by name and block range. The .on method subscribes to new events as they're mined. Indexed parameters (from, to) are filterable; non-indexed (value) is decoded from the event data.

## Code

```javascript theme={null}
import { ethers } from "ethers";

const abi = [
  "event Transfer(address indexed from, address indexed to, uint256 value)",
  "function name() view returns (string)",
];

const provider = new ethers.JsonRpcProvider("https://rpc.ankr.com/eth");
const contract = new ethers.Contract(tokenAddress, abi, provider);

// Query historical Transfer events in the last 10,000 blocks
const currentBlock = await provider.getBlockNumber();
const events = await contract.queryFilter(
  "Transfer",
  currentBlock - 10_000,
  currentBlock
);
console.log(`Found ${events.length} Transfer events`);

// Listen to new Transfer events in real-time
contract.on("Transfer", (from, to, value, event) => {
  console.log(`${from} -> ${to}: ${ethers.formatEther(value)}`);
});
```

***

**Canonical knowledge ID:** `code-example:read-contract-events-ethers`