Server-Side Remote Experiment with Amplitude

This project implements a proper server-side remote experiment using Amplitude's Node.js SDK, following the official documentation.

Architecture

• Backend: Node.js server with Amplitude Experiment Node.js SDK
• Frontend: HTML/CSS/JS client that calls backend API
• Experiment: test-sever-side-remote with control and treatment variants
• Tracking: Automatic exposure tracking via server-side Amplitude Analytics

Setup Instructions

1. Install Dependencies

npm install

2. Start the Server

# Development (with auto-restart)
npm run dev

# Production
npm start

3. Access the Application

Open your browser to: http://localhost:3000

How It Works

Server-Side Remote Flow

1. User clicks property → Frontend sends request to /api/experiment
2. Backend fetches variants → Uses Experiment.initializeRemote() with server deployment key
3. Backend tracks exposure → Automatically sends $exposure event to Amplitude
4. Backend returns variants → Frontend applies styling based on variant
5. Exposure data appears → In Amplitude Experiment dashboard

API Endpoints

• GET /api/experiment - Fetch experiment variants for a user
• GET /api/health - Health check endpoint
• GET / - Serve frontend application

Environment Variables

PORT=3000  # Server port (optional, defaults to 3000)

Configuration

Deployment Keys

• Server Key: server-J2Hw5SNQsPvvJFgOqjeQfecowTIoxD3X (used by Node.js SDK)
• Analytics Key: a3f7a8d1c910f8fabc60dd7e947438f1 (used for tracking)

Experiment Details

• Flag: test-sever-side-remote
• Variants: control (blue buttons), treatment (red buttons)
• Tracking: Automatic exposure events via server-side Analytics SDK

Troubleshooting

Check Server Logs

The server logs will show:

• Experiment SDK initialization
• Variant fetch requests
• Exposure event tracking
• Any errors

Check Network Requests

In browser dev tools, verify:

• Calls to /api/experiment are successful
• Variants are returned correctly
• No CORS errors

Check Amplitude Dashboard

• Exposure events should appear in Experiment dashboard
• Events should have correct flag_key and variant values
• User properties should be populated correctly

Files

• server.js - Node.js backend with Experiment SDK
• package.json - Dependencies and scripts
• index.html - Frontend HTML with API client
• script.js - Frontend JavaScript with experiment logic
• style.css - CSS styling