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Why Run Ethereum in JavaScript?

JavaScript has emerged as an ideal environment for running Ethereum, offering unique advantages for both developers and end-users. Here's why running an Ethereum node in JavaScript unlocks powerful new capabilities.

Performance & Efficiency

โšก Zero Network Latency

Running the EVM locally eliminates round-trip delays to remote nodes, enabling near-instantaneous transaction simulations and gas estimations.

๐Ÿ”„ Powerful JS interop

Simulate multiple transactions plugging directly into the evm with JS or even writing custom contracts in JS.

Real-World Performance Benefits

const gasEstimate0 = await provider.estimateGas({ ... }) // ~200ms as it fetches state
const gasEstimate0 = await provider.estimateGas({ ... }) // ~Instant on future estimations with cache saved
const gasEstimate0 = await provider.estimateGas({ ... }) // ~Instant on future estimations with cache saved

Enhanced User Experiences

JavaScript-based EVM execution enables entirely new categories of dApp features:

๐Ÿ“ฑ Offline Capabilities

Enable local-first applications that work without constant network connectivity.

โšก Optimistic UI

Show users the likely outcome of transactions before they're mined on-chain.

๐Ÿ›ก๏ธ Improved Reliability

Reduce dependency on external infrastructure, making dApps more resilient.

๐Ÿงฎ Transaction Simulation

Simulate complex interactions and preview results before sending transactions.

๐Ÿ” Enhanced Privacy

Process sensitive data locally without sending it to external services.

๐Ÿš€ Accelerated Development

Ship advanced UX faster and safer using Tevm bundler's typesafe Solidity imports, eliminating contract integration errors.

Developer Experience Advantages

Advanced Debugging ๐Ÿ”ฌ

Step through EVM execution opcode by opcode, inspect memory and stack, and see exactly what happens in your contracts.

// Use tevmContract for easy debugging with execution hooks
const result = await client.tevmContract({
  to: contractAddress,
  abi: contractAbi,
  functionName: 'myFunction',
  args: [param1, param2],
  
  // Listen to every EVM instruction
  onStep: (data, next) => {
    console.log(
      `${data.pc.toString().padStart(5)}:`,
      `${data.opcode.name.padEnd(10)}`,
      `gas: ${data.gasLeft.toString().padStart(8)}`,
      `stack: ${data.stack.join(', ')}`
    )
    next()
  }
})

Deterministic Testing ๐Ÿงช

Create fully reproducible environments for testing with complete control over blockchain state, time, and mining.

// Create a snapshot before test
const snapshotId = await client.tevmSnapshot()
 
// Run the test
await client.setBalance({ address: testAccount, value: parseEther("100") })
await client.sendTransaction({ ... })
await client.mine({ blocks: 1 })
const result = await client.call({ ... })
 
// Restore state after test
await client.tevmRevert({ snapshotId })

Portable Environment ๐Ÿ’ผ

The same Ethereum environment works across Node.js, browsers, serverless functions, and other JavaScript runtimes.

import { createMemoryClient } from 'tevm'
 
// Create an in-browser Ethereum node
const client = createMemoryClient()
 
document.querySelector('#button').addEventListener('click', async () => {
  const balance = await client.getBalance({
    address: '0x...'
  })
  console.log(`Balance: ${formatEther(balance)} ETH`)
})
import { createMemoryClient } from 'tevm'
 
// Create a Node.js Ethereum node
const client = createMemoryClient()
 
async function main() {
  const balance = await client.getBalance({
    address: '0x...'
  })
  console.log(`Balance: ${formatEther(balance)} ETH`)
}
 
main().catch(console.error)
import { createMemoryClient } from 'tevm'
 
export async function handler(event) {
  // Create a serverless Ethereum node
  const client = createMemoryClient()
  
  const balance = await client.getBalance({
    address: event.address
  })
  
  return {
    statusCode: 200,
    body: JSON.stringify({ balance: balance.toString() })
  }
}

Solidity Imports

Tevm Bundler (optional feature) creates the best devx for working with solidity files in TypeScript

// Import solidity files directly into TS files
import { MyContract } from "./MyContract.sol";

The devx is optimized in following ways:

  • Natspec on hover
  • Typesafe contract
  • TRPC like experience. You will see red underlines before you even save a solidity file
  • No need to set up external build tools. Plugs directly into your existing js pipeline

JavaScript Ecosystem Integration

๐Ÿ”ค TypeScript

Type-safe contract interactions with full IntelliSense support

โš›๏ธ UI Frameworks

React, Vue, Svelte and other frontend libraries

๐Ÿ—๏ธ Build Tools

Vite, Webpack, ESBuild and other bundlers

๐Ÿงช Testing

Vitest support via Vite

๐Ÿ”„ Runtimes

Node.js, browsers, Electron, serverless functions

๐Ÿ“ฆ NPM Ecosystem

Access to millions of packages and libraries in the npm registry

๐ŸŒ Web APIs

Integration with browser storage, WebSockets, service workers, and more

Ready to Get Started?

๐Ÿ“ Getting Started Guide
๐Ÿ“„ Install Tevm
๐Ÿ“„ Configure Your Environment
๐Ÿ“„ Run Your First Code