What is CRO (conversion rate optimization)
CRO (conversion rate optimization) is the work of getting a larger share of your website's visitors to do what you want, such as buying or leaving their details, by changing the site based on data and checking each change with A/B tests.
By Fernando Blanco Dosil · Updated November 2, 2026
What CRO means, and what it doesn't
A quick note, because the acronym is overloaded: search for "CRO" on its own and you will also find the Cronos cryptocurrency and the Chief Revenue Officer role. Here we mean conversion optimization for websites and online stores.
Conversion optimization is not about bringing in more visitors; that is SEO or advertising. It is about getting more out of the visitors you already have. If your store gets 20,000 sessions a month and sells in 1.5% of them, moving to 1.8% means 60 more orders without spending another euro on ads.
How the conversion optimization cycle works
Every serious CRO programme repeats the same cycle. The difference between teams that improve and teams that don't is usually discipline, not ideas.
- Research: find where people drop off (which page, which device, which channel) and why, using analytics and what your customers tell you.
- Write a hypothesis: "if I change this for these people, this metric will improve, because…".
- Prioritize: you can't test everything at once, so ideas are ranked by impact, confidence and ease.
- Test: build the change as an A/B test and show it to part of your traffic.
- Learn: read the result honestly, keep what works and record what doesn't, because that teaches you something too.
CRO and what it often gets confused with
Three related disciplines that aim at different things.
| What it aims for | How it is measured | |
|---|---|---|
| CRO (conversion) | More visitors converting | Conversion rate, revenue per visitor |
| SEO | More visits from search engines | Rankings and organic traffic |
| Website redesign | Changing the whole site at once | Often not measured against the old one |
Where to start with CRO for your store
Start with the pages the money flows through: product page, cart and category page. And start with mobile, which in most online stores is already more than half the traffic and usually converts worse.
Before you launch anything, decide what a conversion is for you. Without a clear goal, any test can be read as a success.
How Bixlow does it
Bixlow is an AI CRO agent that runs that cycle with you. It installs with one script on any website (Shopify, WooCommerce, PrestaShop, WordPress, Webflow or a custom build), proposes conversion hypotheses, builds the variants on your site without a developer and launches them as A/B tests or personalizations per audience. Nothing is published without your approval, and the result is decided by a Bayesian statistics engine with a minimum sample and a minimum duration. The free plan includes a conversion analysis of your site with hypotheses and up to two published changes; A/B tests and audiences start on the Standard plan.