# Viem — TypeScript Interface for Ethereum

> Viem is a modern TypeScript library for interacting with the Ethereum blockchain. It provides composable, type-safe modules for public client reads, wallet actions, contract interactions, ABI encoding, and ENS resolution. Viem is the low-level transport layer that powers Wagmi and has become the successor to ethers.js for many TypeScript-first teams.

## Install

Save in your project root:

# Viem — TypeScript Interface for Ethereum

## Quick Use
```bash
npm install viem

# In your script
# import { createPublicClient, http } from 'viem';
# import { mainnet } from 'viem/chains';
# const client = createPublicClient({ chain: mainnet, transport: http() });
# const block = await client.getBlockNumber();
```

## Introduction
Viem is a TypeScript-first Ethereum library built by the wevm team (the creators of Wagmi). It takes a composable, tree-shakeable approach where each action is an independent function rather than a method on a large class. Viem replaces ethers.js and web3.js for developers who want strict TypeScript safety and minimal bundle sizes.

## What Viem Does
- Reads chain state through a Public Client with actions like `getBalance`, `getBlock`, and `readContract`
- Signs and sends transactions via a Wallet Client connected to a local key or browser wallet
- Encodes and decodes ABI data, function selectors, event logs, and EIP-712 typed data
- Resolves ENS names and supports reverse resolution
- Provides chain definitions for 100+ EVM networks out of the box

## Architecture Overview
Viem is organized around three client types: Public Client (read-only RPC calls), Wallet Client (signing and sending transactions), and Test Client (Anvil/Hardhat node manipulation). Each client accepts a chain definition and a transport (HTTP, WebSocket, IPC, or custom). Actions are standalone functions that take a client as the first argument, making them composable and tree-shakeable. ABI types are fully inferred at the TypeScript level, so contract method names, argument types, and return types are checked at compile time.

## Self-Hosting & Configuration
- Install with `npm install viem` and import only the modules you need
- Create clients with `createPublicClient` or `createWalletClient` specifying chain and transport
- Use `viem/chains` to import pre-configured chain objects or define custom ones
- For browser DApps, use `custom(window.ethereum)` as the transport with a Wallet Client
- Configure batch JSON-RPC via the `batch` option on the HTTP transport for reduced latency

## Key Features
- Full TypeScript inference on contract reads and writes based on ABI literals
- Tree-shakeable architecture keeps production bundles small
- Built-in multicall batching for efficient on-chain reads
- Human-readable ABI support alongside standard JSON ABIs
- Zero dependencies beyond TypeScript types

## Comparison with Similar Tools
- **ethers.js** — Class-based API with a larger footprint; Viem is functional, tree-shakeable, and has stricter types
- **web3.js** — Plugin-oriented legacy library; Viem offers modern TypeScript ergonomics
- **Wagmi** — React hooks layer built on Viem; Viem is the framework-agnostic core
- **Alloy** — Rust equivalent by the same ecosystem; Viem serves the TypeScript/JavaScript side

## FAQ
**Q: Is Viem a replacement for ethers.js?**
A: Many teams adopt Viem as a modern alternative. It offers better TypeScript inference and smaller bundles, though ethers.js remains widely used.

**Q: Does Viem work in the browser?**
A: Yes. Viem works in browsers, Node.js, Deno, and Bun with no environment-specific dependencies.

**Q: How does ABI type inference work?**
A: When you pass an ABI as a `const` assertion, Viem infers function names, argument types, and return types at the TypeScript level, catching errors before runtime.

**Q: Can I use Viem without Wagmi?**
A: Yes. Viem is a standalone library. Wagmi is an optional React/Vue layer built on top of it.

## Sources
- https://github.com/wevm/viem
- https://viem.sh

---
Source: https://tokrepo.com/en/workflows/asset-b5e57160
Author: AI Open Source