whats-best.ai

Conversion Optimization

Varify.io

EU-Made Report an error

Panel rating · 6 judges · How to read the stars

Category median

Sovereignty: 3 of 4 dimensions proven

0–5 in half steps. 5 means the rubric's top anchor is met on the evidence.

by Varify Software GmbH · varify.io

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Read this page as one judge. Each weighs the same scores by what they care about.

The Data Protection Officer

Weighted verdict

Has to answer whether the test script may run before the consent banner is answered, and usually finds the vendor has not said. Wants the storage keys listed, a documented consent-pending mode, visitor data processed in the EU, and a published subprocessor list that includes the CDN.

Same scores as the panel view — this lens weights them the way this judge cares.

Scored by The Data Protection Officer

Experiment types & delivery

How this is scored

What can be tested and where: client-side changes through an editor, server-side and feature experiments through SDKs, multivariate and multi-page tests, and personalisation — judged on what the documentation shows rather than on the feature grid.

0 — Simple A/B split of one page element through a visual editor; no server-side option, no targeting beyond URL.

3 — Client-side A/B and split-URL tests with basic audience targeting, and no SDK or server-side delivery.

5 — Client-side and server-side experiments through documented SDKs for common languages, multivariate and multi-page tests, audience targeting on behaviour and attributes, and rule-based personalisation.

8 — Feature-flag-based experiments sharing one audience and metric model with web tests, mutually exclusive experiment groups, holdouts, edge or CDN delivery, and personalisation that can itself be tested against a control.

10 — One experimentation programme across every surface: web, app, server and edge from the same platform, experiment interactions managed, a documented experiment lifecycle from hypothesis to archived result, and a library of past results a team can search.

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The Data Protection Officer

The documentation shows client-side A/B, redirect and split-URL tests, full-factorial multivariate and multi-page experiments, mutual exclusion and audience targeting, all served through the visual editor. Server-side A/B testing appears only as a feature listing, and we found no public information on documented SDKs, feature flags, holdouts or edge delivery, so the programme stays client-side in substance. 5 6 11 13

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Statistical method & guardrails

How this is scored

Which statistics decide the winner and what protects the customer from misreading them. Scored on what the vendor documents: the method by name, how peeking and multiple comparisons are handled, and whether sample ratio mismatch is detected.

0 — A "winner" or "probability to beat" figure with no documented method, no stated sample-size guidance and no warning against stopping early.

3 — The method is named (frequentist or Bayesian) but its assumptions are not documented, and nothing prevents a test from being called while it is still underpowered.

5 — Documented method with confidence or credible intervals, a sample-size or test-duration calculator, and stated guidance on when a result may be read.

8 — Sequential testing or an equivalent documented protection against peeking, correction for multiple metrics or variants, sample ratio mismatch detection, variance reduction such as CUPED, and guardrail metrics that can stop a harmful test.

10 — The statistics are auditable: methodology published in enough detail to reproduce a result, the choice of method explained per use case, raw per-visitor data available for independent re-analysis, and the interface refuses to present an underpowered result as a conclusion.

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The Data Protection Officer

The default method is named and partly specified — a one-sided chi-square test for rates and a one-sided t-test for value metrics, with a Bayesian option in the Pro plan — and published guidance says to ignore interim results and run at least ten days with at least 500 conversions per variant. We found no public information on confidence or credible intervals, correction for multiple metrics, or sample ratio mismatch detection. 7 8 13

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Snippet performance & flicker

How this is scored

The cost the client-side snippet imposes on the page it tests: blocking load, flicker of original content, script weight and the effect on Core Web Vitals — scored on what the vendor measures and publishes, not on "lightning fast".

0 — A synchronous snippet with no stated size, no flicker handling and no mention of performance.

3 — An anti-flicker snippet that hides the page until the test loads, with a timeout, and no published figures for script size or load cost.

5 — Script size and loading behaviour documented, asynchronous loading option, flicker handling explained with its trade-off, and CDN delivery of the snippet.

8 — Published performance figures including impact on Core Web Vitals, a self-hosting or first-party-domain option for the script, per-project bundles containing only active experiments, and a server-side or edge alternative for flicker-sensitive tests.

10 — Performance is a stated commitment: measured overhead published and maintained, flicker eliminated by edge or server-side rendering as a documented path, and tooling that shows the customer what their own configuration costs the page.

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The Data Protection Officer

The snippet is published at 11.5 KB, head placement is recommended against flicker, and the optional anti-flicker script is documented with its configurable four-second hide and its stated negative effect on Core Web Vitals. We found no public information on an asynchronous loading option, CDN delivery of the snippet, self-hosting on a first-party domain, or measured figures for the snippet's own effect on Core Web Vitals. 10 11 12

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Analytics, data export & integrations

How this is scored

Getting results and raw data out: integration with analytics and tag management, export of visitor-level results, warehouse-native analysis, and an API — because an experiment result that cannot be checked in the customer's own data is a claim, not a finding.

0 — Results visible in the vendor's dashboard only; no export, no analytics integration, no API.

3 — CSV export of aggregated results and one analytics integration, with no visitor-level data and no documented API.

5 — Integrations with common analytics and tag managers, export of results, and a documented API for managing experiments and reading results.

8 — Visitor-level raw data export or streaming to a data warehouse, warehouse-native analysis on the customer's own metrics, CDP integration for audiences, and an API with stated limits.

10 — The platform treats the customer's warehouse as the source of truth: metrics defined once and computed there, full historical experiment data exportable in open formats, and a versioned API a team can build its own programme tooling on.

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The Data Protection Officer

Integrations with the common analytics and tag tools are documented alongside export of results, and the BigQuery integration delivers raw, line-by-line experiment data into the customer's own project without sampling — data the customer keeps under their own control. We found no public information on stated API limits or a CDP integration; the Experiment API is described only as an expert function. 12 13 14

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European sovereignty

How this is scored

Where visitor data is processed and stored and who the contracting entity is. Independently sourced by the sovereignty pipeline; weighted higher here than in categories that hold only the customer's own data, because the script runs on every visitor to the customer's site and their behaviour is what the platform records.

0 — Non-EU vendor and contracting entity, hosting unstated, subprocessors unnamed, and visitor data leaving the EU without a stated safeguard.

3 — EU data residency offered as an option or an enterprise add-on while the contracting entity is non-EU, or the subprocessor list is absent.

5 — EU processing of visitor data as standard and an EU contracting entity, but parts of the chain — CDN, support access, analytics — are non-EU without an explained safeguard.

8 — EU hosting on named infrastructure including the delivery of the snippet, EU contracting entity, subprocessor list published, and a DPA covering the visitor data the script collects.

10 — Sovereign end to end and evidenced: vendor, entity, hosting, snippet delivery and every subprocessor European, certification published, and no visitor data reaching a non-EU party at any point.

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The Data Protection Officer

The contracting entity is German, hosting is claimed as Frankfurt for the product, and EU processors are named for some functions — but the residency statement sits in marketing copy while the privacy policy shows the website chain processing data with US providers, including Cloudflare processing in the USA. We found no public information on a subprocessor list for the hosted testing product itself, on its hosting provider, or on a data processing agreement covering the visitor data the script collects; SOC 2 is marked only as coming soon, and the imprint names Varify Software GmbH while the privacy policy names Varify GmbH as controller. 1 2 3 4 10

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Pricing transparency

How this is scored

A category priced by traffic — monthly tracked users, visitors or impressions — where the tier a site lands in depends on numbers the buyer has to estimate. Whether a buyer can compute the real annual cost including traffic limits, overage, server-side or personalisation modules and seats — from public pages alone.

0 — No public prices at all; every tier is a sales conversation.

3 — A starting price or a free tier exists, but the traffic metric, the limits and what happens above them are unstated — the invoice is unknowable.

5 — Tier prices public with the traffic metric and its limits defined, but at least one commonly needed piece (server-side SDKs, personalisation, overage) is unpriced or "contact sales".

8 — Every tier priced publicly with the traffic metric defined, limits, overage rates, module prices, minimum term and VAT treatment stated.

10 — Complete price computability: annual invoice derivable for a given traffic volume, set of modules and team size, with overage and every add-on published.

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The Data Protection Officer

Tier prices are public with the traffic metric defined as unlimited monthly tracked users, limits for websites and active experiments stated, and a 15-day full-product trial without a credit card. Multiple domains are on request, AI features are billed in credits without a published price, VAT treatment is not stated, and the captured pages give different figures for the entry price — "For just €119 per month" on the homepage, "ab 199€/Monat" on the German page and 249 € monthly on the plans page. 1 4 10

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European sovereignty — proven facts

3 of 4 dimensions proven

Built only from facts shown on the vendor's own pages. A dimension we could not prove is left open, not scored as zero.

Ownership Not determined — uncited Report an error
Data residency EU only ⚠ unverified 3/3 pts 1 Report an error
Subprocessors US CLOUD Act reach ⚠ unverified 0/2 pts 2 Report an error

Where this could be wrong

What we left out

A claim that does not survive our checks costs us the claim, not the page. This is what was taken off this one.

Sources (14)

The pages every claim on this page was read from — each one checked, dated, and kept verifiable.

  1. 1 Vendor homepage varify.io Checked 22 Sep 2026 Details →
  2. 2 Privacy policy varify.io Checked 22 Sep 2026 Details →
  3. 3 Legal notice varify.io Checked 22 Sep 2026 Details →
  4. 4 Pricing page varify.io Checked 30 Sep 2026 Details →
  5. 5 Experiment types & delivery — found from sitemap varify.io Checked 1 Oct 2026 Details →
  6. 6 Experiment types & delivery — found from sitemap varify.io Checked 1 Oct 2026 Details →
  7. 7 Statistical method & guardrails — found from sitemap varify.io Checked 1 Oct 2026 Details →
  8. 8 Statistical method & guardrails — found from sitemap varify.io Checked 1 Oct 2026 Details →
  9. 9 Consent & visitor tracking — found from sitemap varify.io Checked 1 Oct 2026 Details →
  10. 10 Consent & visitor tracking — found from sitemap varify.io Checked 1 Oct 2026 Details →
  11. 11 Snippet performance & flicker — found from sitemap varify.io Checked 1 Oct 2026 Details →
  12. 12 Snippet performance & flicker — found from sitemap varify.io Checked 1 Oct 2026 Details →
  13. 13 Analytics, data export & integrations — found from sitemap varify.io Checked 1 Oct 2026 Details →
  14. 14 Analytics, data export & integrations — found from sitemap varify.io Checked 1 Oct 2026 Details →