They answer completely different questions
Google Lighthouse and Conversion Probe both score your landing page. But they're measuring different things entirely.
Lighthouse asks: Is this page technically sound? Conversion Probe asks: Will this page persuade someone to act?
A page can score 100 on Lighthouse and still convert at 1%. Speed, accessibility, and SEO best practices matter — but they won't fix unclear copy, missing trust signals, or a CTA that creates friction instead of reducing it.
You need both tools. They're complementary, not competing.
What Google Lighthouse measures
Lighthouse is Google's free auditing tool, built into Chrome DevTools. It scores your page across four categories: performance (load speed, Largest Contentful Paint, Cumulative Layout Shift), accessibility, SEO, and best practices. It tells you whether your page is fast, crawlable, and technically correct. Every developer should run it.
But Lighthouse can't read your headline and tell you it's confusing. It can't detect that your pricing section creates anxiety instead of confidence. It has no opinion on whether your social proof is believable or your CTA is compelling.
What Conversion Probe measures
Conversion Probe analyzes the psychology of your page — the layer that determines whether a technically perfect page actually converts visitors into customers. It scores four dimensions: clarity (can visitors understand your offer in 5 seconds?), trust (do they believe you?), urgency (why act now?), and emotion (does the page connect?).
The Pro report goes deeper with 7 behavioral science frameworks — including Cialdini's persuasion principles, Kahneman's dual-process model, and friction point analysis — then delivers copy rewrites and a prioritized action plan.
Side-by-side comparison
| Google Lighthouse | Conversion Probe | |
|---|---|---|
| What it measures | Page speed, accessibility, technical SEO, best practices | Clarity, trust, urgency, emotion — the conversion psychology layer |
| Who should use it | Developers and technical marketers | Founders, marketers, and anyone writing landing pages |
| When to run it | Before launch and after every deploy | Before launch and whenever conversion rates stall |
| What it can't tell you | Whether your copy persuades, whether visitors trust you, where psychological friction lives | Whether your page loads fast, whether your HTML is accessible, whether Google can crawl it |
Which to run first
If your page is slow or broken, run Lighthouse first. A 6-second load time will kill conversions before psychology gets a chance to work.
If your page loads fine but isn't converting, start with Conversion Probe. The problem is almost certainly in your messaging, trust signals, or page structure — none of which Lighthouse can detect.
For most founders and marketers, the highest-leverage move is fixing persuasion. A fast page with weak copy stays a fast page with low conversions. A slightly slower page with strong psychology still converts.
Use both
Lighthouse makes sure visitors can see your page. Conversion Probe makes sure they act on it. Run Lighthouse to fix the technical foundation, then run Conversion Probe to fix everything else.