A/B and A/B/n testing

Test more. Guess less.

Turn an idea into a live experiment the same day. The agent builds every variant on your real site, Bixlow splits the traffic and measures, and you decide with a verdict you can trust.

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Bixlow A/B tests compare a page's Original with one or more variants that an AI agent builds as injected code, with deterministic in-browser assignment and a Bayesian verdict that only declares a winner when the evidence is there.

yourstore.com/product

Original

89 €Add to cart

Variant B

89 €Add to cart

The agent proposes

Move price and button above the first viewport on mobile.

Variant B

96%probability B is best

Test types: A/B and A/B/n
Who builds it: The agent, no developer
Traffic split: Deterministic, weighted
Verdict: Bayesian, with guardrails

THE PROBLEM

Why almost nobody tests as much as they would like

The idea is the easy part. The hard part is everything between the idea and a result you can defend in front of leadership.

Every variant needs a developer

Moving a block or changing a line of copy becomes a ticket competing with the roadmap. The test ships weeks later, if it ships.

Data gets mixed

Someone changes the split mid-test or a visitor lands in two experiments at once, and the result no longer means anything.

Winners are called too early

Three good days and a screenshot are enough to crown a variant that never repeats its result.

Win one metric, lose another

The variant lifts add-to-cart clicks and nobody notices revenue per session went down.

HOW IT WORKS

From hypothesis to verdict

A test in Bixlow is a mode of the workflow: the Original is still your page, and each variant is a draft of its own.

1
Frame the hypothesis
Describe the change in your own words or let the agent propose it from your data: problem, change, audience and primary metric.
2
The agent builds the variants
Each variant is built as injected code on your real site. You review it in the preview before anything is published.
3
Split and launch
Choose each variant's weight and how much of your traffic enters the test. Every visitor always sees the same version.
4
Read the verdict
The statistics engine tells you when there is a real winner. Declare it and that variant becomes the page's base version.

CAPABILITIES

Everything a test needs to be trustworthy

The part you never see in a screenshot — assignment, exclusion, restarts — is what makes the result mean something.

Variants

A/B and A/B/n from the same workflow

The Original plus as many variants as you need, each with its own draft and version history.

Each variant is edited separately, by the agent or a person.
Preview any variant before publishing.
Declaring a variant the winner makes it the base version.

Assignment

Every visitor, always in the same group

Assignment happens in the browser with a first-party identifier, so it is stable across visits and never breaks your site's caching.

Configurable weight per variant.
You decide what share of traffic enters the test.
Mutual exclusion groups for tests that overlap.

Clean measurement

Data that never mixes

Change the split or a variant while the test runs and measurement starts again from that moment.

Every conversion is attributed to the variant the visitor saw.
A primary goal plus guardrails that must not get worse.
Automatic sample ratio mismatch (SRM) check.

AI AGENT

The agent builds the test; you decide if it ships

It is not an assistant that helps you write CSS. It builds complete variants, sets up measurement and reads the result.

You decide

Which page and which goal matter now.
Which metric must not get worse.
The split and the traffic that enters the test.
Publishing: nothing reaches your site without your approval.

The agent does

Proposes the hypothesis and the variant from your data.
Builds the variant in your brand's look.
Sets up goals and guardrails.
Reads the verdict and proposes the next test.

A test in Bixlow

Page: Product page
Variant B: Sticky add-to-cart bar on mobile
Split: 50 / 50 · 80% of traffic
Primary metric: Purchase
Guardrail: Revenue per session
Verdict: Waiting for minimum sample · day 4 of 7

BIXLOW STUDIO

Want a testing program, not a one-off test?

Bixlow Studio designs the roadmap, builds and launches tests every week and walks you through them, with a strategist approving every step.

Meet Bixlow Studio

01Funnel audit and a prioritized list of hypotheses.
02New tests every week on your site.
03Results read with a senior strategist.

KEEP EXPLORING

FREQUENTLY ASKED QUESTIONS

A/B testing

Do I need a developer to run an A/B test?

No. You install the script once, and from then on the agent builds each variant as code injected into your site. You can review and edit what it builds before publishing.

How many variants can I test at once?

A test can have the Original plus several variants (A/B/n). The more variants, the more traffic you need to reach a verdict, and the statistics engine accounts for that.

Can a visitor see different variants on each visit?

No. Assignment is deterministic and stored in the browser, so each visitor always sees the same variant of the same test.

What happens if I change the split while a test runs?

Measurement restarts from that moment so data from two different setups never mixes.

Will it slow my site down?

The script loads asynchronously and fails silently: if Bixlow can't be reached, your site renders exactly as it would without it.

Which plan includes A/B tests?

A/B tests are part of the Premium plan. Goals and analytics are in every plan, so you can start by measuring and run tests when you need them.

GET STARTED

Your first test, today

Install the script, tell the agent what you want to test and review the variant before it goes live.