Replacing Google Optimize: A/B Testing with Alternatives

We help companies replace Google Optimize after its shutdown. Many site owners have faced integrations that stopped working. We offer migration to modern A/B testing tools: from open-source GrowthBook to corporate VWO and Optimizely. We preserve historical data and ensure seamless integration with GA4. Our experience: over 30 successful migrations in 5 years.

Google Optimize Replacement: How to Migrate Without Data Loss?

First, we assess the current infrastructure: which tests were running, how goals are set in GA4, whether there are custom events. Then we choose a suitable replacement. Among popular options are VWO, Optimizely, AB Tasty, Statsig, Eppo, and open-source GrowthBook documentation. Below is a comparison of key features.

For most of our clients, GrowthBook is the optimal choice: it's free, supports A/B tests, feature flags, and integrates easily with GA4.

Why open-source is better than proprietary?

Open-source tools give you full control over data and architecture. You are not tied to a vendor and can customize functionality for your tasks. For example, GrowthBook allows storing experiments on your own server, which is critical for companies with high security requirements. We use GrowthBook in projects where transparency and scalability are needed.

Practical case: migration from Google Optimize to GrowthBook

Let's consider a real task: a client used Optimize for A/B testing a CTA button on a landing page. The test had two variants: control and variant A. Data was sent to GA4. After Optimize shutdown, all tests stopped working, but historical data remained in GA4.

Deploying GrowthBook

# Docker installation docker-compose up -d # from official docker-compose.yml # Dashboard: http://localhost:3000 

After startup, create a project and obtain the SDK key.

SDK integration

// SDK integration import { GrowthBook } from '@growthbook/growthbook' const gb = new GrowthBook({ apiHost: 'https://cdn.growthbook.io', clientKey: 'sdk-abc123', enableDevMode: true, trackingCallback: (experiment, result) => { gtag('event', 'experiment_viewed', { experiment_id: experiment.key, variant_id: result.variationId, }) } }) await gb.loadFeatures() // Usage in component const ctaText = gb.getFeatureValue('cta_text', 'Buy now') const showBanner = gb.isOn('promo_banner') 

Transferring an existing test

Replace the old Google Optimize callback with a GrowthBook call:

// Before (Google Optimize) gtag('event', 'optimize.callback', { name: 'ABCxxx', callback: (value, name) => { console.log('Experiment:', name, 'Variant:', value) } }) // After (GrowthBook) const variant = gb.getFeatureValue('experiment_name', 'control') // Then manually apply the variant 

The test is running; data flows to GA4 through the same gtag. It took about an hour for integration and another hour for verification.

What's included in the work

• Audit of current experiments and GA4 integrations
• Selection of the optimal replacement tool
• Deployment and configuration of the chosen solution (GrowthBook, VWO, or other)
• Migration of all active tests with event schema preservation
• Integration with GA4 for test data transmission
• Testing A/B test functionality (correct distribution and event firing)
• Documentation of the new system and team training
• Guarantee of correct operation after migration

Process of work

1. Analytics — study current Optimize configuration, GA4, list of active experiments.
2. Design — choose a replacement, design integration architecture.
3. Implementation — deploy the tool, write/copy test code.
4. Testing — verify correct distribution, event tracking, absence of errors.
5. Deployment — go live, monitor initial results.

Timelines and cost

Migration timeline: from 2 to 5 working days depending on the number of tests and integration complexity. Cost is calculated individually after an audit. Typical migration costs range from $1,500 to $5,000, saving you up to 80% compared to proprietary tool licenses. Get a free consultation.

Typical mistakes during migration

• Using incompatible attributes when transferring tests (e.g., different event types)
• Missing fallback values for feature flags (if SDK doesn't load, the site should work in the control state)
• Ignoring cache cleanup of old experiments (removing Optimize scripts)

We guarantee that after migration all tests will work correctly, and data in GA4 will remain consistent. Our experience: over 30 successful A/B testing migrations in 5 years. Order migration now.

// feature-flags.js const EXPERIMENTS = { 'hero_headline': { variants: ['control', 'variant_a'], weights: [0.5, 0.5] } } function assignVariant(experimentId) { const stored = sessionStorage.getItem(`exp_${experimentId}`) if (stored) return stored const exp = EXPERIMENTS[experimentId] const random = Math.random() let cumulative = 0 let chosen = exp.variants[0] for (let i = 0; i < exp.variants.length; i++) { cumulative += exp.weights[i] if (random < cumulative) { chosen = exp.variants[i] break } } sessionStorage.setItem(`exp_${experimentId}`, chosen) gtag('event', 'experiment_viewed', { experiment_id: experimentId, variant_id: chosen }) return chosen }