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This guide provides detailed instructions for installing and setting up OnchainTestKit in your project.

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System Requirements

OnchainTestKit requires the following software to be installed on your system:
  • Node.js: Version 14 or higher
  • Package Manager: npm, yarn, bun, or pnpm
  • Foundry: For running local Anvil nodes
  • Operating System: macOS, Linux, or Windows (with WSL2)

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Installation Steps

  • yarn
  • npm
  • bun
# Install OnchainTestKit and Playwright
yarn add -D @coinbase/onchaintestkit @playwright/test

# Install Playwright browsers with system dependencies
yarn playwright install --with-deps

# Download wallet extensions
yarn prepare-metamask
yarn prepare-coinbase

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Installing Foundry

OnchainTestKit uses Anvil (part of Foundry) for local blockchain nodes. Install Foundry using the official installer: 
# Install Foundry
curl -L https://foundry.paradigm.xyz | bash

# Update PATH (may need to restart terminal)
source ~/.bashrc

# Verify installation
anvil --version
For Windows users, we recommend using WSL2 for the best experience. Foundry works natively on macOS and Linux.

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Environment Configuration

Create a .env file in your project root with the following variables:
.env
# Test wallet seed phrase (NEVER use production wallets!)
E2E_TEST_SEED_PHRASE="test test test test test test test test test test test junk"

# Optional: Fork configuration for testing against mainnet state
E2E_TEST_FORK_URL="https://mainnet.base.org"
E2E_TEST_FORK_BLOCK_NUMBER="12345678"

# Optional: Smart contract project root
E2E_CONTRACT_PROJECT_ROOT="../smart-contracts"
Never commit .env files to version control. Add .env to your .gitignore file.

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Project Structure

We recommend organizing your tests in the following structure: 
your-project/
├── e2e/
│   ├── tests/
│   │   ├── connect.spec.ts
│   │   ├── transactions.spec.ts
│   │   └── contracts.spec.ts
│   ├── config/
│   │   ├── metamask.config.ts
│   │   └── coinbase.config.ts
│   └── helpers/
│       └── wallet.helpers.ts
├── src/                    # Your application code
├── .env                    # Environment variables
└── playwright.config.ts    # Playwright configuration

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Playwright Configuration

Create a playwright.config.ts file:
playwright.config.ts
import { defineConfig, devices } from "@playwright/test"
require("dotenv").config({ path: "./.env" })

/**
 * Read environment variables from file.
 * https://github.com/motdotla/dotenv
 */


// Use process.env.PORT by default and fallback to port 4000
const PORT = process.env.PORT || 4000

// Set webServer.url and use.baseURL with the location of the WebServer respecting the correct set port
const baseURL = `http://localhost:${PORT}`

/**
 * See https://playwright.dev/docs/test-configuration.
 */
export default defineConfig({
  timeout: 120000,
  testDir: "./e2e",
  /* Run tests in files in parallel */
  fullyParallel: false,
  /* Fail the build on CI if you accidentally left test.only in the source code. */
  forbidOnly: !!process.env.CI,
  /* Retry on CI only */
  retries: process.env.CI ? 3 : 0,
  /* Opt into parallel tests on CI. */
  workers: 10,
  maxFailures: 3,
  /* Reporter to use. See https://playwright.dev/docs/test-reporters */
  reporter: "line",
  /* Shared settings for all the projects below. See https://playwright.dev/docs/api/class-testoptions. */
  use: {
    /* Base URL to use in actions like `await page.goto('/')`. */
    baseURL,

    /* Collect trace when retrying the failed test. See https://playwright.dev/docs/trace-viewer */
    trace: "on-first-retry",
  },

  /* Configure projects for major browsers */
  projects: [
    {
      name: "chromium",
      use: { ...devices["Desktop Chrome"] },
    },

    // {
    //   name: 'firefox',
    //   use: { ...devices['Desktop Firefox'] },
    // },

    // {
    //   name: 'webkit',
    //   use: { ...devices['Desktop Safari'] },
    // },

    /* Test against mobile viewports. */
    // {
    //   name: 'Mobile Chrome',
    //   use: { ...devices['Pixel 5'] },
    // },
    // {
    //   name: 'Mobile Safari',
    //   use: { ...devices['iPhone 12'] },
    // },

    /* Test against branded browsers. */
    // {
    //   name: 'Microsoft Edge',
    //   use: { ...devices['Desktop Edge'], channel: 'msedge' },
    // },
    // {
    //   name: 'Google Chrome',
    //   use: { ...devices['Desktop Chrome'], channel: 'chrome' },
    // },
  ],

  // Run your local dev server before starting the tests:
  // https://playwright.dev/docs/test-advanced#launching-a-development-web-server-during-the-tests
  webServer: {
    command: "yarn start -p 4000",
    url: baseURL,
    timeout: 30 * 1000,
    reuseExistingServer: !process.env.CI,
  },
})

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Verifying Installation

Run this command to verify everything is installed correctly: 
# Check Node.js
node --version

# Check Playwright
npx playwright --version

# Check Anvil
anvil --version

# List installed browsers
npx playwright show-browsers

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Next Steps

Now that you have OnchainTestKit installed, you’re ready to: