EthereumJS Monorepo

Modular TypeScript libraries for Ethereum execution-layer protocol work.

Composable, spec-tested building blocks for the Ethereum execution layer: EVM execution, transactions, blocks, state, tries, and chain configuration. Use them in Node.js or the browser — tree-shakeable, Noble crypto by default, WASM-free unless you opt in.

• Spec-tested execution — tracks mainnet hardforks (status ↓)
• Composable primitives — mix tx, block, mpt, statemanager, and friends instead of pulling in a full client
• Browser-ready — controlled dependency set; package READMEs cover bundler and KZG setup where needed

Maintained by former members of the Ethereum Foundation JavaScript team and the broader Ethereum community.

Hardfork status

What do you want to do?

flowchart TD
  start[What_are_you_building]
  start --> txRules[Tx_and_block_rules]
  start --> bytecode[Bytecode_only]
  start --> chainData[Chain_storage_or_types]

  txRules --> vmPkg["@ethereumjs/vm"]
  bytecode --> evmPkg["@ethereumjs/evm"]
  chainData --> blockPkg["@ethereumjs/block / blockchain"]

Quick start

Install the VM (includes EVM, tx, and state wiring):

npm install @ethereumjs/vm @ethereumjs/common @ethereumjs/tx @ethereumjs/util

Run a simple signed transfer against an in-memory state (adapted from packages/vm/examples/runTx.ts):

import { Common, Hardfork, Mainnet } from '@ethereumjs/common'
import { createLegacyTx } from '@ethereumjs/tx'
import {
  createAccount,
  createAddressFromPrivateKey,
  createZeroAddress,
  hexToBytes,
} from '@ethereumjs/util'
import { createVM, runTx } from '@ethereumjs/vm'

const common = new Common({ chain: Mainnet, hardfork: Hardfork.Prague })
const vm = await createVM({ common })

const senderKey = hexToBytes(`0x${'20'.repeat(32)}`)
const sender = createAddressFromPrivateKey(senderKey)
await vm.stateManager.putAccount(sender, createAccount({ nonce: 0n, balance: BigInt(1e18) }))

const tx = createLegacyTx({
  gasLimit: 21000n,
  gasPrice: 1_000_000_000n,
  value: 1n,
  to: createZeroAddress(),
}).sign(senderKey)

const res = await runTx(vm, { tx })
console.log(res.totalGasSpent) // 21000n

For bytecode-only execution use @ethereumjs/evm (examples). For blob (EIP-4844) transactions you need a separate KZG library — see KZG setup in the tx README.

Package map

Active packages (published in sync on v10; see scripts/release-npm.ts):

Codec and primitives

Configuration

Protocol types

State

Execution

Chain storage

Other packages

How packages fit together

flowchart BT
  rlp --> util --> common
  common --> tx & block & mpt & genesis
  mpt --> block & statemanager
  tx --> block --> vm
  statemanager --> evm --> vm
  block --> blockchain

Full responsibility matrix, execution flow (runBlock → runTx → evm), and release notes: ARCHITECTURE.md.

Contribute

Releases: active development on master (v10). Maintenance branches and breaking-release policy: DEVELOPER.md § Releases.

Clone and build:

git clone https://github.com/ethereumjs/ethereumjs-monorepo.git
cd ethereumjs-monorepo
git submodule update --init
npm install

Tooling, CI, conventions, and release process: DEVELOPER.md · CONTRIBUTING.md.

Deprecated packages (no longer updated)

Package	Role
@ethereumjs/client	Full execution client (deprecated)
@ethereumjs/devp2p	devp2p networking (deprecated)
@ethereumjs/wallet	Key management helpers (deprecated)

Still on npm for migration reference; do not start new projects on these packages.

Community

The EthereumJS GitHub organization is maintained by the former Ethereum Foundation JavaScript team and contributors. Join Discord for questions and follow the Code of Conduct.

Related: Lodestar — TypeScript consensus client and SSZ tooling for the Ethereum consensus layer.

License

Most packages are MPL-2.0 licensed; see each package folder for its license file.