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
⚡ Zero Network Latency
Running the EVM locally eliminates round-trip delays to remote nodes, enabling near-instantaneous transaction simulations and gas estimations.
🔄 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 savedEnhanced User Experiences
JavaScript-based EVM execution enables entirely new categories of dApp features:
📱 Offline Capabilities
Enable local-first applications that work without constant network connectivity.
⚡ Optimistic UI
Show users the likely outcome of transactions before they're mined on-chain.
🛡️ Improved Reliability
Reduce dependency on external infrastructure, making dApps more resilient.
🧮 Transaction Simulation
Simulate complex interactions and preview results before sending transactions.
🔐 Enhanced Privacy
Process sensitive data locally without sending it to external services.
🚀 Accelerated Development
Ship advanced UX faster and safer using Tevm bundler's typesafe Solidity imports, eliminating contract integration errors.
Developer Experience Advantages
Advanced Debugging 🔬
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 🧪
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 💼
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
🔤 TypeScript
Type-safe contract interactions with full IntelliSense support
⚛️ UI Frameworks
React, Vue, Svelte and other frontend libraries
🏗️ Build Tools
Vite, Webpack, ESBuild and other bundlers
🧪 Testing
Vitest support via Vite
🔄 Runtimes
Node.js, browsers, Electron, serverless functions
📦 NPM Ecosystem
Access to millions of packages and libraries in the npm registry
🌐 Web APIs
Integration with browser storage, WebSockets, service workers, and more