Local Fork Block Number Pinning Tool

WHAT IT DOES

The Local Fork Block Number Pinning Tool is a developer tool that fetches and displays detailed block information from the connected RPC provider, designed specifically for configuring local blockchain forks. It retrieves the block number, hash, parent hash, timestamp, gas usage, transaction count, and other metadata for any specified block or the latest block. The tool presents this information in a clear, readable format and provides a ready-to-use Foundry Anvil fork command with the pinned block number. This helps developers quickly obtain the necessary block data to create deterministic, reproducible local development environments.

HOW TO USE

Connect your wallet to establish an RPC provider connection. Enter a block number (e.g., "19000000") or use "latest" to fetch the most recent block. Click "pin block" to retrieve and display the block's metadata. The tool shows the block number prominently, along with the block hash, parent hash, timestamp, transaction count, gas usage, gas limit, block size, difficulty, and state root. A pre-formatted Anvil fork command is generated automatically, using the pinned block number. Copy this command to your terminal to fork the chain at that exact block using Foundry's Anvil.

TECHNICAL MECHANISM

The tool uses the connected RPC provider to fetch block data via ethers' getBlock() method. For block numbers, it calls getBlock(number) with the provided integer. For "latest", it calls getBlock('latest') to fetch the most recent block. The provider returns a Block object containing all standard Ethereum block fields: number, hash, parentHash, timestamp, gasUsed, gasLimit, transactions array, difficulty, nonce, size, extraData, and stateRoot. The tool extracts and displays these fields, formatting timestamps as readable dates and rendering hashes with full visibility. The Anvil fork command is constructed using the pattern: "anvil --fork-url PROVIDER_URL --fork-block-number BLOCK_NUMBER". The provider URL is placeholder text since the tool cannot access the provider's full URL, but the command structure is ready for the user to complete. The tool validates block existence and handles errors gracefully, providing clear feedback if the block is not found or the provider is unreachable.

WHAT IT CANNOT SEE

The tool cannot actually create or manage local forks—it only provides the block information needed to configure them. It cannot verify that a block is safe for forking without node-specific validation. The tool cannot detect if a block is on a chain that may reorganize, which could affect fork stability. It cannot determine if the block contains transactions that may affect fork consistency. The tool cannot account for provider-specific block availability—archive nodes may have older blocks that full nodes do not. It cannot validate that the forked state will be consistent without executing the fork. The tool cannot predict if the fork will succeed given your node configuration or network conditions.

PLEASE NOTE

This tool is designed for Ethereum Virtual Machine (EVM) compatible chains only. The generated Anvil command is a suggestion—you must replace "YOUR_PROVIDER_URL" with your actual RPC endpoint. The tool requires a connected wallet provider; some providers may not support fetching older blocks if they are not archive nodes. The tool provides block information only and does not execute forks or validate fork compatibility. Always test your fork in a development environment before relying on it for critical testing. Different RPC providers may return different block data depending on their sync status.