---
name: get-block-number
description: Get the latest block number for a blockchain using Web3.py and JSON-RPC environment variables
---
# Get latest block number
This skill retrieves the latest block number from a blockchain using the configured JSON-RPC environment variables and Web3.py.
ALWAYS USE SCRIPT. NEVER RELY ON THE HISTORICAL INFORMATION OR GUESS.
## Required inputs
1. **Chain name**: The blockchain to query (e.g., Ethereum, Arbitrum, Base, Polygon)
## Running the script
Generate and run a Python script to fetch the block number.
Run it Python commadn line inline, don't write a new file.
```python
import os
from web3 import Web3
from eth_defi.provider.multi_provider import create_multi_provider_web3
# Replace {CHAIN} with the uppercase chain name
json_rpc_url = os.environ.get("JSON_RPC_{CHAIN}")
if not json_rpc_url:
raise ValueError("JSON_RPC_{CHAIN} environment variable not set")
web3 = create_multi_provider_web3(json_rpc_url)
block_number = web3.eth.block_number
print(f"Latest block number: {block_number}")
```
Run the script with:
```shell
source .local-test.env && poetry run python <script_path>
```
## Display output
Return the block number to the user in a clear format, e.g.:
```
Chain: Ethereum
Latest block number: 19,234,567
```
