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probant.
Log inCreate your workspace
From idea to rollout, in one tool.Product overview

Prepare

Decide

Roll out

Scale

Visual editorBuild the variant without a developer, with the assistant.Test plan and durationDuration calculated before the first visitor.IdeasEach idea estimated from your past tests.Metrics and marginNo-code goals, margin calculated from your orders.
ReportsA one-sentence verdict, with revenue and margin in euros.Session recordings and click mapsSee what visitors do with each variant.GuardrailsA test that breaks something stops on its own.
RolloutsStep by step, with automatic rollback.PersonalizationAn experience for one audience, measured against a holdout.Feature flagsTurn a feature on by rule, and off in one click.
Learnings libraryThe effects of your finished tests, on one scale.Installation and integrationsTwo lines of code, in the browser or on the server.Team and governanceRoles, launch approvals, and an audit log.
Explore the demo Pricing
The rules behind every verdict, set before launch.The full method

The method, step by step

How Probant decidesThe peeking trapThe winner’s curseThe statistics engineGlossaryVerify a report
MethodThe winner’s curseWhy the reported gain is too good, on average.See the correction
Revenue per visitor · Free shipping progress bar
Measured lift+6.0%
After correction+4.9%
+€125,700per month after correction, instead of +€153,300

Corrected using the demo store’s 48 finished tests.

Rerun the simulation with your own number of tests and duration.A/A simulator
By site area and by team.All use cases

You are…

Know what pays off, without a statistician.

The features that matter to you:

ReportsA one-sentence verdict, with revenue and margin in euros.Metrics and marginNo-code goals, margin calculated from your orders.Visual editorBuild the variant without a developer, with the assistant.See the use case
Cart · demo storeFree shipping progress barConclusive. Proven gain+€125,700 per month · revenue per visitor +6.0%, range +2.2% to +10.0%

Computed by the engine on a demo test.

By site areaCart and shippingProduct pageCheckoutMobile navigationCategory pages
Explore the demo
Blog, docs, and tools.All resources
A/A simulatorSee for yourself what peeking costs.Why checking a test every day produces false winners.Run the simulator
BlogMethod, measurement, and lessons learned.
Nov 12What is an A/B test? Definition, steps, and an exampleNov 7Measure margin, not just revenueNov 7The winner’s curse: why the announced gain falls short
All articles
Duration calculatorHow many days it takes to detect the effect you want.DocumentationInstall the script, handle consent, send events.Video tutorialsInstall, launch a test, and read a report, on video.ComparisonsProbant vs. other tools, with sources.AB TastyKameleoonVWOOptimizelyAdobe TargetDynamic Yield+11 more
ChangelogWhat changed in Probant, by date.Case study formatContext, test, result, and decision, on the demo store.Migrate to ProbantImport your AB Tasty, VWO, or Kameleoon history, recalculated by Probant.
Articles, docs, and calculators, free to use.
One fixed monthly price, no overage charges.See pricing

How many visitors do you test each month?

A tested visitor is each unique visitor who sees a test or a rollout during the month. It’s the only thing that sets the price.

Billing
Your planEssential€590/monthor €5,900 per yearFor a store that tests continuously, down to revenue per visitor.
  • Up to 250,000 tested visitors per month
  • All features, unlimited tests within your volume
  • No overage charges
Choose Essential
Your bill never goes over your plan. Once you reach the volume, running tests keep going.Billing questions

One tool, from idea to rollout.

Probant helps you build the variant, computes the test plan before the first visitor, ends each test with a one-sentence verdict in euros, then rolls out the winner with guardrails.

Create your workspaceExplore the demo
  • Open demo, no sign-up
  • Figures computed on a fictional store
Free shipping progress bar
Conclusive. Proven gain

Showing progress toward free shipping: revenue per visitor +6.0% measured, +4.9% expected once corrected for the winner’s curse. The effect on margin isn’t established yet: +3.0% measured, range from -0.7% to +6.7%.

Measured difference+6.0%
After correction+4.9%
Expected revenue / month+€125,700+€41,600 to +€209,800
Plan locked on Oct 2318 days3 checkpoints · boundaries 3.47, 2.45, 2.00
Test plan guardrails
Return rateWithin limit
Mobile speed (LCP)Within limit

Five steps, from the first click to the library.

Every test follows the same path: the editor feeds the test plan, the plan sets how the report is read, and the report decides the rollout.

  1. 1Build the variantIn the visual editor, on your real page, or in one sentence with the assistant.
  2. 2Set the test planTarget effect, visitors, duration, and checkpoints, computed from your traffic and then locked.
  3. 3Read the verdictOne sentence, a range, and a euro amount corrected for the winner’s curse.
  4. 4Roll outIn steps, with guardrails checked at each checkpoint and automatic rollback.
  5. 5LearnEach completed test joins the library and sharpens the next estimates.

The product’s 13 features.

Each card shows a figure computed on the demo store or read from the product itself.

Prepare

Decide

Roll out

Scale

Verdicts that hold up.

A misread A/B test produces winners that earn nothing. Probant applies rules set before launch, and shows them.

These examples come from the demo store’s “Free shipping progress bar” test, except the last one, which comes from another test.

How Probant decides
The test plan is locked at launch
Free shipping progress bar: 18 days, 3 checkpoints, and a target effect of 5.5%, set on Oct 23, before the first visitor.
Decisions happen only at planned checkpoints
On day 6, z = 2.30 was already above the classic threshold of 1.96, but below the boundary of 3.47, so the test continued. The boundary was crossed on day 18 (z = 3.09).
The reported gain is corrected
+6.0% measured, +4.9% reported: the winner’s curse correction draws on the store’s 48 completed tests.
The traffic split is checked
Chi-square test on the visitors in A and B (p = 0.81). A sample ratio mismatch hides the results until it is diagnosed.
A guardrail can stop everything
“You may also like” recommendations was switched back to the original on Nov 10 at 05:12: return rate went from 1.6% to 2.9%.

The method, in detail.

The peeking trapWhy checking a test every day produces false winners.Learn more The winner’s curseWhy the reported gain is too good, on average.Learn more The statistics engineIts methods, their sources, and how each is verified.Learn more

Next: Visual editor

See this feature in the demo, on the screen this page describes, or move on to the next one.

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