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From idea to rollout, in one tool.Product overview

Prepare

Decide

Roll out

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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

Probant vs. Varify.io

Both tools compared point by point, based on Varify.io’s public documentation, accessed November 11, 2026. Every statement about Varify.io links to its source.

37 sources from 15 official pages, accessed November 11, 2026.

What Varify.io offers.

Varify.io is a visual A/B testing platform for marketing and CRO teams, published by Varify Software GmbH, near Munich.12 Its monthly price is fixed, whatever the site’s traffic.3 The default test is frequentist; Bayesian is limited to the Pro plan.45

Probant is for sites that want A/B test verdicts that hold up, with a plan set before launch and guardrails monitored through rollout. It measures what each conversion is worth: the margin on an order, a qualified or signed lead, a paid subscription.

The differences, point by point.

On the left, what Varify.io’s public documentation says, each sentence with its source. On the right, what Probant does. “Not mentioned” means nothing was found in that documentation, which does not prove a feature is missing.

Probant and Varify.io, point by point. Note numbers link to the sources at the bottom of the page.
CriterionVarify.ioProbant
Statistical methodOne-sided frequentist tests by default (chi-square for rates, Student’s t-test for values such as RPV); the Pro plan adds two-sided and Bayesian. The method is set for the whole account, not per experiment.45Frequentist, with a sequential plan set before launch: target effect, duration, and checkpoints. The verdict fits in one sentence, with a 95% range. Where to check
PeekingThe documentation recommends ignoring interim significance and waiting for the final result; sequential testing is announced as coming (“SOON”) on the Enterprise plan.67Decisions are only made at planned checkpoints, with O’Brien-Fleming boundaries: very strict at first, close to the usual threshold at the end. During a rollout, ranges are always valid (mSPRT), so you can check them at any time. Where to check
Traffic split (SRM)An automatic sample ratio mismatch (SRM) check is not mentioned in their public documentation (as of November 11, 2026).The traffic split is checked with a chi-square test every time the report is read. If the split is off, the test moves to “blocked” status and no winner is declared. Where to check
GuardrailsAn option stops an experiment automatically when a defined result condition is met.8 Guardrails that stop a test on their own are not mentioned in their public documentation (as of November 11, 2026).Guardrail metrics are tracked with their range; a guardrail is only breached if the whole range crosses the limit. A breached guardrail blocks the test’s verdict, stops a running test on its own, and during a rollout moves visitors back to the original automatically. Where to check
Gradual rolloutsA winning variant can stay live in one click, and allocation accepts decimals for a gradual ramp-up; no automatic rollback on metric degradation is documented.910Steps of 25% → 50% → 100% by default, 10% → 25% → 50% → 100% in cautious mode. Automatic rollback when a guardrail is breached; an exposed visitor stays exposed in the following steps. Where to check
Multi-armed banditThe multi-armed bandit is listed on the Enterprise plan with the label “SOON” (upcoming).11Optimization test: Thompson sampling, reallocated at most once a day, with a minimum share per variant. It maximizes a conversion rate, or an amount per visitor such as revenue: purchase probability and average order value drawn from their distributions, with values capped at a percentile as in an A/B test. Optionally, shares per device (mobile, tablet, desktop): one draw per device, each with its own learning and floor. A visitor always keeps their variant: a new split only applies to visitors who arrive after it. The screen says so: it maximizes conversions (or the amount per visitor) during the test, without proving that a variant is better. The difference is read period by period (and device by device), with no declared winner; the CSV export gives the same reading. Where to check
Revenue and margin per visitorSignificance on revenue and ARPU (t-test) on all plans; no confidence interval on revenue per visitor is documented.1213 A guide suggests price tests to find the best contribution margin.14 Margin per visitor is not mentioned in their public documentation (as of November 11, 2026).Revenue and margin per visitor, each with its range; the gain is stated in euros. Margin is calculated on the server from reconciled orders, the cost of each product (Shopify or CSV), and store fees; no margin verdict below 90% of revenue covered by known costs. Where to check
Winner’s curseA winner’s curse correction is not mentioned in their public documentation (as of November 11, 2026).The reported gain is corrected for the winner’s curse by Bayesian shrinkage toward the effects of the store’s past tests. Where to check
Bayesian modeBayesian mode (Pro plan) shows a probability that the variant beats the original and a duration forecast up to 95%. The choice of prior and expected loss are not documented.1516Optional, off by default: a Bayesian reading next to the verdict, with the probability that the variant does better, the credible interval, and the expected loss of each choice. The prior is centered on zero and as wide as the effects measured by the store’s completed tests; while there are too few of them to estimate it, the Bayesian reading is not shown. The decision always follows the sealed plan; when the two readings disagree, the report explains why. Where to check
Multiple comparisonsThe documentation states that the risk of a false winner grows with each added metric.17 A multiple comparisons correction is not mentioned in their public documentation (as of November 11, 2026).Segment comparisons are corrected with the Holm method. With several variants, the error risk is split across comparisons (Bonferroni). Where to check
Multivariate testingA Varify page about multivariate testing states that the tool generates all combinations and splits traffic evenly. The pricing page, the features page, and the user documentation mention “multi-variation testing” (A/B/n), without describing a multivariate test. Interaction reporting points to BigQuery.1819Full factorial design generated by Probant: two to four sections, each with two to four levels, up to sixteen combinations, each served as a variant. Main effects of each section across all traffic and interactions between two sections, corrected with the Holm method on the comparisons stated in the plan. Based on the workspace’s measured traffic, the plan says whether the test can reach a conclusion and suggests removing a level or a section; no best combination is declared without a check. Where to check
Variance reduction (CUPED)Variance reduction (CUPED) is not mentioned in their public documentation (as of November 11, 2026).CUPED applied to live test reports, using each visitor’s history before their first exposure; without history, the difference stays unadjusted and the report says so. Where to check
Visual editorNo-code visual editor and HTML/CSS/JavaScript editor on all plans; the Chrome extension lets you try the editor and run QA without the snippet installed.2021Two ways to edit, producing the same changes: a page preview loaded by Probant, without its scripts, or the live page on the site, scripts included. On the site, the editor is loaded by the script already installed, through a short-lived signed link for one draft and one variant, with no browser extension. It only sends the chosen changes to Probant. Where to check
Widgets“Campaign Booster”: USP bar, notification, info bar, exit layer, back-to-top arrow; the Shopify Checkout app adds components (USP list, shipping progress bar) that can be tested or deployed.2223Banner, countdown, pop-up, badge, reassurance, action bar, delivery date, social proof, promo code, free shipping, and survey, set up without code in the editor and saved in the workspace library for other tests. A widget is just a set of ordinary changes: escaped text, links over https or to the site, and styles applied without a style attribute, so a strict CSP does not need loosening. The countdown follows the site’s time zone and disappears at the deadline; the pop-in opens on arrival, on exit intent, or after scrolling, closes with the keyboard, and does not reappear during the visit if consent allows. Their small modules only load for visitors in the variant. The delivery date is calculated in the visitor’s browser (cutoff time, business days, public holidays); social proof shows the exact number of purchases received over a rolling week, and only above a threshold. The survey asks up to 8 questions (closed answers, recommendation scale, open question) with conditional logic, on the page or through a link outside the site (email, QR code), based on 70 templates (recommendation, satisfaction, effort, checkout blockers, cancellation, concept test, multi-question surveys…); open answers are redacted before sending (email addresses, phone numbers, cards, IBANs), kept for 180 days, and grouped by theme; each question is read by variant, with its range and response rate, and comparisons across all questions are corrected together; a response through a link is attached to the variant the visitor saw, recalculated by Probant, or stays outside the test. Where to check
Script and flicker11.5 KB snippet, synchronous or asynchronous; an optional anti-flicker script, placed before the snippet, hides the page (opacity 0) until the variant is applied.242526Script under 7 KB compressed, loaded asynchronously, that does not hide the page while it loads. Server-side assignment available, for a display with no flicker at all. Where to check
Granular permissionsThree system roles (Admin, Publisher, Editor) from the Pro plan; creating roles and assigning individual permissions are limited to the Enterprise plan.2728Four fixed roles, plus custom roles the owner builds from a catalog of named permissions: prepare, launch and stop, roll out, approve a launch, write variant JavaScript, manage flags, metrics, margin, members, and keys. No privilege escalation: billing, roles, transfer, and deletion of the workspace stay with the owner; no one can grant more than their own permissions, and an API key cannot exceed its author’s. Where to check
Data hostingApplication hosted on AWS in Frankfurt; script delivered through Cloudflare’s global network. Subprocessors are listed in Annex 5 of the DPA.29Database and compute in Amsterdam, with Scaleway, in the European Union. Scaleway, which hosts the database and compute, is a French company. Published subprocessor list: Scaleway (Amsterdam, Netherlands (nl-ams region), in the European Union), Brevo (European Union: servers in France and Germany, encrypted backups in Belgium (Google Cloud), according to Brevo), Mistral AI (European Union by default (European API endpoint), according to Mistral), ClickHouse (option not used), Stripe (Contract with Stripe Payments Europe, Ltd. (Ireland); data transferred to Stripe, LLC (United States), according to Stripe), Sentry (European Union: Frankfurt (Germany), including backups, according to Sentry). Depending on the feature used, Mistral may temporarily transfer data outside the European Union to the subprocessors it publishes; its data processing agreement limits these transfers to countries the EU recognizes as adequate, or covers them with standard contractual clauses. Stripe transfers payment data to Stripe, LLC, in the United States, under the Data Privacy Framework and, failing that, standard contractual clauses. Whatever region is chosen, Sentry may keep the data of Probant’s Sentry account (members, settings, audit log, project descriptions) in the United States; reported errors stay in Frankfurt. Where to check
Consent by defaultVarify sets no cookies and stores the assignment in localStorage/sessionStorage; a consent option is built in, and Varify leaves it to the customer’s legal review to decide whether it is needed. This mode delays tracking; the snippet can also be installed without consent, in which case variants are shown directly.303132Consent required by default: no cookie, no assignment, and nothing sent before the visitor agrees. Consent given mid-page: the page does not change in front of the visitor; their variant starts on the next page. First-party cookie, lasting 390 days at most, never extended. Where to check
Pricing modelFlat fee per domain: Growth €199/month and Pro €249/month billed annually (€249 and €349 monthly), Enterprise from €799/month; unlimited traffic when measurement goes through GA4 or BigQuery. With another analytics tool, Varify Realtime Tracking is priced individually by MTU; AI credits extra. Monthly or annual commitment (also semiannual on Pro).333435Creating a Probant workspace is free; paid plans cost €590 to €1,990 per month depending on the number of tested visitors (2 months free with annual billing), with no overage charges. Agency plan: 1,000,000 tested visitors per month, shared across client workspaces, from 3 workspaces, for €1,490 per month or €14,900 per year. Where to check

What Varify.io also does.

Probant shares these points with Varify.io.

  • A visual editor

    No-code visual editor and HTML/CSS/JavaScript editor on all plans; the Chrome extension lets you try the editor and run QA without the snippet installed.2021

  • EU hosting

    Application hosted on AWS in Frankfurt; script delivered through Cloudflare’s global network. Subprocessors are listed in Annex 5 of the DPA.29

  • A Bayesian reading

    Bayesian mode (Pro plan) shows a probability that the variant beats the original and a duration forecast up to 95%. The choice of prior and expected loss are not documented.1516

  • An asynchronous script that does not hide the page

    11.5 KB snippet, synchronous or asynchronous; an optional anti-flicker script, placed before the snippet, hides the page (opacity 0) until the variant is applied.242526

When to choose Varify.io over Probant.

Based on Varify.io’s public documentation.

  • You want a fixed price that does not depend on traffic

    Flat fee per domain: Growth €199/month and Pro €249/month billed annually (€249 and €349 monthly), Enterprise from €799/month; unlimited traffic when measurement goes through GA4 or BigQuery. With another analytics tool, Varify Realtime Tracking is priced individually by MTU; AI credits extra. Monthly or annual commitment (also semiannual on Pro).333435

  • You already measure everything in GA4 or BigQuery

    From the Pro plan, Varify runs its SQL queries in the customer’s BigQuery project (GA4 export) to evaluate experiments on raw data; no other data warehouse (Snowflake, Redshift…) is mentioned.3637

  • You want Shopify checkout components

    “Campaign Booster”: USP bar, notification, info bar, exit layer, back-to-top arrow; the Shopify Checkout app adds components (USP list, shipping progress bar) that can be tested or deployed.2223

What sets Probant apart.

These points are not in Varify.io’s public documentation, accessed November 11, 2026. A missing mention does not prove a feature is missing; if these points matter to you, ask Varify.io.

  • Margin per visitor

    Probant measures revenue and margin per visitor, each with its range.

    Varify.ioA guide suggests price tests to find the best contribution margin.14 Margin per visitor is not mentioned in their public documentation (as of November 11, 2026).

    Learn more

  • Winner’s curse correction

    The reported gain is corrected by Bayesian shrinkage toward the effects of the store’s past tests.

    Varify.ioA winner’s curse correction is not mentioned in their public documentation (as of November 11, 2026).

    Learn more

  • SRM that blocks the verdict

    A traffic split imbalance moves the test to “blocked” status, and no winner is declared.

    Varify.ioAn automatic sample ratio mismatch (SRM) check is not mentioned in their public documentation (as of November 11, 2026).

  • Consent required by default

    No cookie, no assignment, and nothing sent before the visitor agrees.

    Varify.ioVarify sets no cookies and stores the assignment in localStorage/sessionStorage; a consent option is built in, and Varify leaves it to the customer’s legal review to decide whether it is needed. This mode delays tracking; the snippet can also be installed without consent, in which case variants are shown directly.303132 Consent required by default is not mentioned there (as of November 11, 2026).

Frequently asked questions.

How much does Varify.io cost?

Flat fee per domain: Growth €199/month and Pro €249/month billed annually (€249 and €349 monthly), Enterprise from €799/month; unlimited traffic when measurement goes through GA4 or BigQuery. With another analytics tool, Varify Realtime Tracking is priced individually by MTU; AI credits extra. Monthly or annual commitment (also semiannual on Pro).333435 Creating a Probant workspace is free; paid plans cost €590 to €1,990 per month depending on the number of tested visitors (2 months free with annual billing), with no overage charges.

Where does Varify.io host data?

Application hosted on AWS in Frankfurt; script delivered through Cloudflare’s global network. Subprocessors are listed in Annex 5 of the DPA.29 Probant hosts its database and application in Amsterdam, with Scaleway.

Does Varify.io measure margin?

A guide suggests price tests to find the best contribution margin.14 Margin per visitor is not mentioned in their public documentation (as of November 11, 2026). Probant measures revenue and margin per visitor, each with its range, from orders and the cost of each product.

Can you look at Varify.io results while a test is running?

The documentation recommends ignoring interim significance and waiting for the final result; sequential testing is announced as coming (“SOON”) on the Enterprise plan.67 Probant sets its checkpoints before launch (O’Brien-Fleming) and uses always-valid ranges during rollouts.

Sources.

Official pages from Varify.io, accessed November 11, 2026. Quotes are reproduced in their original language.

  1. Source 1: varify.io/llms.txt
    Varify.io is a visual A/B testing and web experimentation platform for marketing and CRO teams.
  2. Source 2: varify.io/en/entity/varify-ab-testing-platform
    The platform is developed and operated by Varify Software GmbH in Grünwald near Munich, Germany.
  3. Source 3: varify.io/en/entity/varify-ab-testing-platform
    Varify.io charges a fixed monthly price starting at €199 — regardless of website traffic.
  4. Source 4: docs.varify.io/en/significance-calculation
    By default, Varify uses two established one-sided statistical tests:
  5. Source 5: docs.varify.io/en/significance-calculation
    In the Pro Plan, a two-sided frequentist method and a Bayesian method are also available.
  6. Source 6: docs.varify.io/en/significance-calculation
    Significance values that occur in between should be ignored - the final result is what counts.
  7. Source 7: varify.io/en/plans
    Sequential testing: Evaluate results continuously and stop a test as soon as significance is reached.SOON
  8. Source 8: varify.io/en/plans
    Auto stop experiments: Stops an experiment automatically once your defined result condition is met.
  9. Source 9: varify.io/en/plans
    Roll out winning variations: Keep a winning variation live with one click, without waiting for a developer release.
  10. Source 10: varify.io/en/plans
    Traffic allocation with decimal places: Allocate traffic precisely, for example 0.5 % for a careful ramp-up.
  11. Source 11: varify.io/en/plans
    Multi-armed bandit: Traffic shifts automatically toward the better-performing variation while the test runs.SOON
  12. Source 12: varify.io/en/plans
    Revenue significance & ARPU: Significance on revenue and average revenue per user, not just conversion rate.
  13. Source 13: varify.io/en/features/multi-variation-testing
    One report per experiment, with improvement, confidence and significance for every goal.
  14. Source 14: docs.varify.io/en/shopify-price-test
    To find out at which price your products achieve the best contribution margin, you can carry out price tests.
  15. Source 15: docs.varify.io/en/significance-calculation
    Unlike the frequentist approach, it does not calculate p-values, but a probability that a variation is better than the original.
  16. Source 16: docs.varify.io/en/significance-calculation
    With the Bayesian method, Varify displays a runtime forecast that estimates when 95 % significance is likely to be reached.
  17. Source 17: docs.varify.io/en/significance-calculation
    Alpha error accumulation increases the probability of a false positive with each additional metric - i.e. a supposed winner that is not actually a winner.
  18. Source 18: varify.io/en/multivariate-testing
    Varify.io supports both A/B testing and multivariate testing within the same platform.
  19. Source 19: varify.io/en/multivariate-testing
    Set up the MVT experiment — Varify automatically generates all combinations and distributes traffic evenly.
  20. Source 20: varify.io/en/plans
    Visual & code editor: Build variations by clicking in the page, or drop into HTML, CSS and JavaScript.
  21. Source 21: docs.varify.io/llms.txt
    Try the visual editor on your own site with the Chrome extension — no code snippet installed.
  22. Source 22: varify.io/en/plans
    Campaign Booster: Pre-defined, easy-to-add elements such as USP bars, notifications or exit-intent layers.
  23. Source 23: docs.varify.io/en/shopify-checkout-app/checkout-shopify-app
    You create components—such as a USP list or a shipping progress bar—and deploy them via an experience, either as an A/B test or directly to all visitors.
  24. Source 24: docs.varify.io/en/iso-27001
    Delivers a lightweight JavaScript snippet (11.5 KB) that applies visual or code-based changes to a website
  25. Source 25: docs.varify.io/en/varify-snippet-implementation
    You have two options for integrating the snippet: synchronous and asynchronous.
  26. Source 26: docs.varify.io/en/anti-flicker-script
    This script can optionally be integrated before the Varify.io® code snippet.
  27. Source 27: docs.varify.io/en/role-permission-management
    Varify offers the 3 standard system roles: Admin, Publisher and Editor.
  28. Source 28: varify.io/en/plans
    Creating new user roles: Define your own roles with exactly the permissions you need.
  29. Source 29: varify.io/en/features
    The application runs on AWS in Frankfurt. Delivery runs through Cloudflare's global network.
  30. Source 30: varify.io/en/features
    Varify sets no cookies. A consent option is built in; whether you need it is up to your legal review.
  31. Source 31: docs.varify.io/en/tracking-via-consent
    This has the advantage that you can, for example, integrate the Varify snippet without consent, whereby experiments are played out directly.
  32. Source 32: docs.varify.io/en/tracking-via-consent
    By triggering tracking, users are permanently assigned to an experiment and variation (local storage) and data is sent to your web analytics tool.
  33. Source 33: varify.io/llms.txt
    Varify pricing: Growth €199/month, Pro €249/month (billed annually), Enterprise from €799/month. Unlimited traffic on every plan, 15-day free trial.
  34. Source 34: varify.io/en/plans
    **Experiment data can be imported from Google Analytics 4 (and BigQuery). With any other analytics provider, experiments are measured with Varify Realtime Tracking – we set that up individually with you based on your MTU.
  35. Source 35: varify.io/en/plans
    Monthly price 249 € 349 € on request
  36. Source 36: varify.io/en/plans
    Evaluation of BigQuery Goals: Evaluate experiments on raw event data instead of sampled reports.
  37. Source 37: docs.varify.io/llms.txt
    The SQL that Varify runs in BigQuery for your reports, and where to read those jobs in the job explorer.

Migrate from Varify.io

Your Varify.io history can be imported as a generic CSV (visitors and conversions per variant) and is reread by Probant’s engine: every verdict is recalculated from visitors and conversions.

Migrate from Varify.ioExplore the demo
  • Open demo, no sign-up
  • Free to start, no overage charges
  • Database and compute in Amsterdam, with Scaleway