# Get Block Number

> Get the latest block number for a blockchain using Web3.py and JSON-RPC environment variables

- Skill: `tradingstrategy-ai/get-block-number` (Agent Skill)
- Install (CLI): `npx skillmds add tradingstrategy-ai/get-block-number`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tradingstrategy-ai/get-block-number/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: tradingstrategy-ai (https://skillmd.com/u/tradingstrategy-ai)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/tradingstrategy-ai/get-block-number

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# 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
```