JavaScript-Native Ethereum Virtual Machine
Tevm puts an Ethereum node anywhere JavaScript runs—Node, browser, serverless, edge, or desktop. Instantly fork mainnet, simulate complex contracts, and run full-stack devnets, all with TypeScript-first safety and blazing speed.
If you use viem, wagmi, 0x, or build modern Ethereum apps, Tevm is the engine that powers next-level shipping, testing, and UX.
- ⚡ Ship at Lightspeed: Instant feedback. Test and deploy with no wait, no Docker, no slow subprocesses. Build and iterate like the Rust and Go elite—now in JS and Zig.
- 🚫 Goodbye, Loading Spinners: Deliver real optimistic UI. Run every contract locally for true instant dapp experiences—no more waiting on RPCs.
- 🔒 TypeScript-Native Confidence: End-to-end type safety and autocompletion. Import Solidity, call contracts, and simulate transactions with zero guesswork.
- 🌐 Mainnet-Grade Simulation: Fork any EVM chain—mainnet, L2, L3—and manipulate state locally with full fidelity.
- 🧪 Unmatched Testing Power: Write robust integration tests, simulate reorgs, verify gas, and check UX edge cases, all in one toolkit.
- 💻 True Local-First: Full EVM in Node, browser, or edge—offline or online, always in your control.
- 🎯 The Fastest Path from Idea to User: Tevm Compiler brings Solidity into your codebase with real types, letting you ship faster and safer than ever before.
- ⚡ Optimistic Updates, Advanced Gas Modeling: Build dapps that feel like Web2 and simulate costs with precision, in JS/TS.
Everything you need to build, simulate, and ship at the speed of your ideas.
Run an EVM devnet anywhere—Node, browser, edge, or serverless. One line, zero dependencies.
import { createMemoryClient } from "tevm";
const client = createMemoryClient();Import Solidity right into TypeScript and call it with full type safety:
import { ERC20 } from '@openzeppelin/contracts/token/ERC20.sol';
import { createMemoryClient } from 'tevm';
const client = createMemoryClient();
const token = ERC20.withAddress("0x123...");
const balance = await client.readContract(token.read.balanceOf("0x456..."));Write contracts inline with sol template literals (coming soon):
import { sol } from 'tevm';
const { MyContract } = sol`
contract MyContract {
function greet() public pure returns (string memory) {
return "hello";
}
}
`;A new EVM core in Zig for true browser and edge-native execution—under 100kb, launching soon. Source
Next-gen plugin for instant optimistic updates, auto-caching, and devnet magic in your frontend.
- 🔄 Test Against Mainnet or Any Chain: Fork and simulate mainnet, L2s, L3s, and custom rollups with a single call.
- 🤖 Prototype Next-Gen Apps: From L2 fraud proofs to LLM/EVM wallets and AI agents—in the browser or edge.
- ✨ Deliver Seamless UX: Eliminate spinners. Build apps that always feel instant.
- ⛽ Model Gas & Simulate Fees: Run "what if" gas scenarios and advanced fee logic, locally and reproducibly.
- 🔍 Debug, Profile, and Introspect: Step through opcodes and inspect contract state in real time.
| Feature | Tevm | Anvil | Hardhat | Ganache | Tenderly |
|---|---|---|---|---|---|
| Language | JS/Wasm (Zig WIP) | Rust | JS/Rust | JS | Go |
| Browser Support | ✅ | ❌ | ❌ | ❌ | ✅ (SaaS) |
| Minimal Dependencies | ✅ | ✅ | ❌ | ❌ | ✅ (SaaS) |
| Viem Integration | Native | Yes (RPC) | Minimal | Minimal | None |
| Forking (L1, Rollups) | ✅ | ✅ | ✅ | Some | ✅ |
| Rebase/Fork Updates | Soon | ❌ | ❌ | ❌ | ✅ |
| Solidity Tests | Some | Yes | Yes | No | No |
| Fuzzing | ❌ | ✅ | ✅ | ❌ | ❌ |
| Open Source | ✅ | ✅ | ✅ | ✅ | ❌ |
Tevm is funded by an Ethereum Foundation grant. Our roadmap:
- ✅ Tevm 1.0.0 Release
- 🔄 Test Library
- 🎮 MUD Integration for onchain games
- 🚀 ZigEvm Launch: Fastest Wasm EVM ever
npm install tevm viem@latestimport { createMemoryClient, http } from "tevm";
import { optimism } from "tevm/chains";
import { parseAbi } from "viem";
// Fork Optimism mainnet
const client = createMemoryClient({
common: optimism,
fork: { transport: http("https://mainnet.optimism.io") },
});
await client.tevmReady();
const account = "0x" + "baD60A7".padStart(40, "0");
await client.setBalance({ address: account, value: 10_000_000_000_000_000_000n });
const greeterAbi = parseAbi([
"function greet() view returns (string)",
"function setGreeting(string memory _greeting) public",
]);
const greeterAddress = "0x10ed0b176048c34d69ffc0712de06CbE95730748";
// Read from contract
const greeting = await client.readContract({
address: greeterAddress,
abi: greeterAbi,
functionName: "greet",
});
// Write to contract
await client.writeContract({
account,
address: greeterAddress,
abi: greeterAbi,
functionName: "setGreeting",
args: ["Hello from Tevm!"],
});
await client.mine({ blocks: 1 });
const newGreeting = await client.readContract({
address: greeterAddress,
abi: greeterAbi,
functionName: "greet",
});- 📖 Getting Started
- 🔗 Viem Integration
- 📦 Ethers Integration
- 🛠️ Bundler Quickstart
- 📚 API Reference
- 💡 Examples
We're always looking for passionate builders—especially if you love TypeScript, Zig, L2/L3s, or pushing the limits of EVM tooling. See CONTRIBUTING.md to get started.
Tevm is fully open source under the MIT license. See LICENSE for details.
Tevm is for you if you're:
- 🔧 Building with viem, wagmi, 0x, or TypeScript-first Ethereum apps
- ⚡ Shipping UIs that need instant feedback (no spinners)
- 🚀 Creating next-gen dapps, rollups, wallets, or LLM/EVM integrations
- 😤 Tired of slow, fragile, or heavyweight devnets
❤️ Ready to level up your Ethereum workflow?
