A/B Testing for WordPress
Run A/B tests on any WordPress site without plugins or performance issues. Install a 5.4KB snippet in your theme head, build variants visually, and optimize conversions while protecting Core Web Vitals.
🚀 Loved by WordPress site owners
Set up A/B testing on your WordPress site in under 60 seconds
How it works on WordPress
Install the Stellar snippet
Add one line of code to your WordPress site head. Direct installation is recommended for anti-flicker and fastest variant delivery.
Create an experiment and variants
Use the no-code visual editor to change headlines, buttons, images, or layout on live pages—no redeploy required.
Configure targeting rules
Limit experiments to specific URLs, devices, or countries so tests only run for the audience that matters.
Add conversion goals
Track form submissions, WooCommerce add-to-cart, button clicks, or visits to thank-you pages.
Analyze results and ship winners
Review real-time stats in Stellar, optionally sync conversions to GA4, and apply the winning variant.
Install the Stellar snippet on WordPress
Paste your snippet in header.php, child theme head, or Insert Headers and Footers plugin. Direct head install is recommended so anti-flicker works correctly. Full install guide →
- Add the Stellar snippet to your WordPress head—via theme header.php, a child theme, or a header plugin
- Avoid duplicating the snippet in both a plugin and theme file
- Exclude stellar.js from WP Rocket, NitroPack, Autoptimize, and similar plugins
- Clear WordPress object cache and CDN after saving
See our install documentation for WordPress-specific optimization plugin exclusions—critical for reliable experiments.
Pre-launch QA checklist
Run through this list before sending traffic to an experiment on WordPress.
- Confirm stellar.js loads in the Network tab on pages where experiments should run
- Verify only one install path is active (direct head install or GTM—not both)
- Match anti-flicker settings to your install method (direct install recommended)
- Clear CDN, theme, or platform cache after saving snippet changes
- Test in an incognito window with ad blockers disabled
- Confirm stellar.js on front-end pages (not wp-admin)
- Add d3niuqph2rteir.cloudfront.net to JS optimization exclusions
- Verify only one snippet install path is active
- Test WooCommerce shop and checkout-adjacent pages if running store experiments
WordPress limitations and gotchas
Optimization and cache plugins
WP Rocket, NitroPack, Autoptimize, and similar tools can minify or defer Stellar. Exclude the snippet or experiments may fail silently.
Page builder overlap
Elementor, Divi, and other builders render front-end HTML differently. Validate targeting on the live URL for your builder. See our Elementor A/B testing page for Elementor-specific notes.
Multisite and headless setups
Standard install assumes classic WordPress front-end rendering. Headless WordPress may require snippet placement in the JS front-end framework instead.
GA4 tracking for WordPress experiments
Stellar sends conversion events to Google Analytics 4 via the Measurement Protocol, so experiment data appears alongside your other WordPress analytics. GA4 integration setup →
Event name: stellar_experiment_conversion
Register these custom dimensions in GA4 (Event scope):
experiment_id,experiment_namevariant_id,variant_nameconversion_id,conversion_name
Keep your WordPress site fast while you test
Stellar's 5.4KB async snippet loads without the bloat of legacy testing platforms—important for SEO and Core Web Vitals on WordPress.
At just 5.4KB and served on a CDN, Stellar's pure JS script is 25x smaller than competitors like VWO or AB Tasty. With minimal dependencies and a fixed size regardless of test count, it preserves your website's speed, Core Web Vitals, user experience, and SEO performance.
Why teams choose Stellar for WordPress
WordPress A/B test ideas to run first
Blog post CTAs
Test inline CTAs and content upgrades on high-traffic posts.
WooCommerce product pages
Optimize product titles, images, and add-to-cart on WooCommerce.
Contact forms
Test Contact Form 7, WPForms, or native form layouts.
Landing pages
Run PPC landing page tests on WordPress without redeploying.
Pricing pages
Compare pricing tables and plan highlight styles.
Mobile menu CTAs
Test mobile navigation vs. sticky header buttons.
Pricing
Free
Up to 25k MTU
Built-in analytics
Visual web editor
Custom CSS & JS editor
AI editor assistant
Basic A/B testing
Up to 3 variants per experiment
Up to 2 experiments running simultaneously
Pro
50k MTU included
Unlimited variants
Unlimited concurrent experiments
Advanced targeting rules
Dynamic keyword insertion
AI insights & recommendations
Priority support
Enterprise
Custom MTU volume
Custom solutions
Integrations support
We dynamically bill in small increments of 1k MTU, so you only pay for what you actually use and never overpay
No hidden fees, no large fixed blocks. Scale smoothly as your traffic grows with predictable, usage-based billing
We only count users who actually see experiments. Multiple experiment views from the same user count as just 1 MTU
Trusted by marketers running experiments
Jake M. — Performance Marketer
⭐️⭐️⭐️⭐️⭐️
Other testing tools have a million features I don't need. Stellar focuses on what actually matters: speed, ease of use, and great analytics.
Richard R. — E-commerce Owner
⭐️⭐️⭐️⭐️⭐️
Stellar is the real deal. No unnecessary features, no steep learning curve. Just quick tests that actually improve our store.
Ben C. — Growth Hacker
⭐️⭐️⭐️⭐️⭐️
It does the job without slowing down our pages. If you're running tests and care about performance, this is the tool to use.
Frequently Asked Questions
More platforms
Stellar works on any site where you can add head code. Explore setup guides for other platforms: