---
title: "execution"
description: "Execution layer crates covering the EVM, chain spec, payload building, storage, transaction pool, and state."
source: https://basehub.org/crates/execution/overview/
---
The `execution` crate group runs the Base node's execution layer. It spans EVM execution, state storage, transaction pool, and payload construction.

## Sub-crates

| Crate | Package Name | Purpose |
|-------|-------------|---------|
| [chainspec](/crates/execution/chainspec/) | `reth-optimism-chainspec` | EVM chain spec for Optimism |
| [cli](/crates/execution/cli/) | `reth-optimism-cli` | Execution layer CLI (jemalloc, OTel) |
| [consensus](/crates/execution/consensus/) | `reth-optimism-consensus` | Block validation and trie roots |
| [evm](/crates/execution/evm/) | `reth-optimism-evm` | Block executor and state transitions |
| [exex](/crates/execution/exex/) | `reth-optimism-exex` | Execution Extensions — proofs with trie updates |
| [hardforks](/crates/execution/hardforks/) | `reth-optimism-forks` | Optimism hardfork definitions |
| [node](/crates/execution/node/) | `reth-optimism-node` | Node builder — assembles all components |
| [payload](/crates/execution/payload/) | `reth-optimism-payload-builder` | Payload construction from pending transactions |
| [primitives](/crates/execution/primitives/) | `reth-optimism-primitives` | Custom transaction and receipt types |
| [reth](/crates/execution/reth/) | `reth-op` | Meta-crate re-exporting all OP reth components |
| [rpc](/crates/execution/rpc/) | `reth-optimism-rpc` | eth\_, debug\_, op\_ RPC namespaces |
| [storage](/crates/execution/storage/) | `reth-optimism-storage` | Database codec implementations |
| [trie](/crates/execution/trie/) | `reth-optimism-trie` | Trie storage for fault proof window |
| [txpool](/crates/execution/txpool/) | `reth-optimism-txpool` | Transaction pool with L1 cost calculation |

## Role in the Architecture

The execution crate group is the heart of the node. It:

1. Defines the Base chain specification including gas limits, hardforks, and genesis (`chainspec`, `hardforks`)
2. Configures and runs the EVM for transaction execution (`evm`)
3. Builds execution payloads from pending transactions (`payload`)
4. Manages the transaction pool for pending transactions (`txpool`)
5. Handles state storage and the Merkle Patricia Trie (`storage`, `trie`)
6. Provides RPC endpoints for querying execution state (`rpc`)
7. Integrates with Reth's execution pipeline (`reth`, `node`)
8. Supports Execution Extensions for custom indexing (`exex`)

Built on top of [Reth](https://github.com/paradigmxyz/reth) v1.11.0, these crates customize Reth's execution engine for the Base L2 environment.

## Source

[`crates/execution/`](https://github.com/base/base/tree/main/crates/execution)