Keyboard shortcuts

Press ← or → to navigate between chapters

Press S or / to search in the book

Press ? to show this help

Press Esc to hide this help

Introduction

mevlog is a simple way to query data from any EVM-compatible chain - locally, on your own machine, without depending on third parties.

It is an open-source (MIT) alternative to commercial blockchain indexers and data APIs. Instead of using a hosted service and querying an external database, mevlog downloads raw chain data straight from an RPC endpoint, stores it in a local SQLite database, and lets you query it with plain SQL. You own the data. No API keys, no rate limits, no vendor lock-in - just a file on your disk that you can query as much as you want, offline.

What you can do with it

  • Download blockchain data efficiently - pull any block range from an RPC node into a local per-chain SQLite store.
  • Keep data in sync - follow the chain head live and prune old blocks to cap storage.
  • Query with SQL - run read-only SQL against indexed transactions, blocks, and logs tables, with custom SQLite helpers for working with 256-bit integers, token amounts, ETH/gwei/USD formatting, and ENS names.
  • Define custom tables - decode the logs you care about (swaps, transfers, any event) into typed columns via config.
  • Inspect single transactions and blocks - render a tx, its logs, or a whole block, plus deeper EVM analysis (state diffs, call traces, coinbase payments).
  • Generate EVM tracing insights - replay any transaction to extract storage state diffs, decoded call traces, and direct coinbase payments. Tracing runs either through a node’s standard debug_traceTransaction RPC, or fully locally via Revm - no tracing-enabled RPC required.
  • Talk to the blockchain over MCP - expose mevlog as a Model Context Protocol server so an AI assistant can query chain data on your behalf.

How it works

mevlog follows a three-step model: index → store → query.

  1. Index - fetch a block range from an RPC endpoint (using cryo under the hood).
  2. Store - write the transactions, blocks, and logs into a local, per-chain SQLite database under ~/.mevlog/.
  3. Query - run SQL against that local store. Because the data lives on your disk, queries are fast and free.

These docs walk through each step. See Quick Start to get set up and run your first query.