What should I use for conversion rate optimization experiments?

For conversion rate optimization (CRO) experiments, the best choice is usually a controlled A/B testing tool with solid analytics and audience targeting. What you should use depends on your stack and traffic volume, but here’s the practical breakdown:

Good options by need

1. If you want an all-in-one CRO platform

Use a tool like:

• Optimizely
• VWO
• Convert
• AB Tasty

These are great if you want:

• A/B and multivariate tests
• Visual editor for pages
• Audience segmentation
• Goal tracking
• Statistical reporting

2. If you want a lightweight, modern setup

Use:

• Google Analytics 4 or Amplitude for measurement
• Feature flag / experiment tooling like LaunchDarkly, GrowthBook, or PostHog
• A custom frontend experiment layer if needed

This is good if you:

• Have engineers available
• Want more control
• Care about product experiments, not just marketing pages

3. If you’re mostly testing landing pages

Use:

• Unbounce
• Instapage
• Webflow experiments or similar tooling

These are useful when you need:

• Fast page changes
• Simple landing-page testing
• Minimal engineering involvement

What matters most

Whichever tool you use, make sure it supports:

• Clear primary metric definition
• Randomized assignment
• Reliable tracking
• Sample size / significance guidance
• Audience segmentation
• Consistent user bucketing across sessions

My recommendation

If you’re starting out:

• Small team / marketing-led: VWO or Optimizely
• Product-led / engineering-friendly: GrowthBook or PostHog
• Landing pages only: Unbounce or Instapage

If you want, I can recommend the best CRO tool for your specific situation based on:

• your traffic level
• your stack
• your budget
• whether you need web, app, or email experiments