localscan 0.1.3

A lightweight EVM blockchain indexer and explorer

LocalScan

A lightweight EVM blockchain indexer and explorer. LocalScan connects to any EVM-compatible node via WebSocket, indexes blocks and transactions in real time into a local SQLite database, and exposes a web UI alongside a REST API for querying chain data.

Features

• Real-time block and transaction indexing via WebSocket (eth_subscribe)
• ERC-20 transfer log tracking and token balance caching
• Address, contract, and token metadata resolution
• Web-based block explorer UI
• REST API for blocks, transactions, and addresses
• SQLite storage — no external database required
• Automatic reconnect and reorg detection

Requirements

• Python 3.10 or higher
• An EVM-compatible node with WebSocket and HTTP RPC endpoints (e.g. Anvil, Hardhat, Geth, Reth)

Installation

From PyPI (pip)

pip install localscan

From Source

git clone https://github.com/your-org/localscan.git
cd localscan
git submodule update --init --recursive
pip install .

Development Install

git clone https://github.com/your-org/localscan.git
cd localscan
git submodule update --init --recursive
pip install -e .

Usage

Start the Explorer

localscan

This starts the indexer and web server on http://127.0.0.1:8000 by default, connecting to a local node at ws://127.0.0.1:8545.

Options

localscan [OPTIONS]

  --host          Bind host (default: 127.0.0.1)
  --port          Bind port (default: 8000)
  --rpc-url       WebSocket RPC URL (default: ws://127.0.0.1:8545)
  --http-rpc-url  HTTP RPC URL for receipts and calls (default: http://127.0.0.1:8545)
  --db            Path to the SQLite database file (default: chain_indexer.db)
  --keep-db       Keep the existing database on startup instead of wiping it
  --reload        Enable auto-reload for development

Example — Connect to a Custom Node

localscan \
  --rpc-url ws://my-node:8546 \
  --http-rpc-url http://my-node:8545 \
  --port 3000 \
  --keep-db

REST API

Method	Endpoint	Description
GET	/blocks/{block_number}	Get block by number
GET	/transactions/{tx_hash}	Get transaction by hash
GET	/addresses/{address}	Get address, contract, and token info

All endpoints return JSON. The web UI is served at /.

Project Structure

localscan/
  app/
    indexer/      # Block ingestion, chain-sniper integration
    db/           # SQLAlchemy models and session
    routes/       # FastAPI route handlers
    templates/    # Jinja2 HTML templates
    static/       # CSS and JS assets
    cli.py        # Entry point
    main.py       # FastAPI application
  chain-sniper/   # WebSocket block subscription submodule
  alembic/        # Database migrations

Database Migrations

LocalScan uses Alembic for schema migrations.

alembic upgrade head

License

MIT — see LICENSE.