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Conversion Optimization

Optimizely

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Panel rating · 6 judges · How to read the stars

Category median

Sovereignty: 1 of 4 dimensions proven

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

by Optimizely North America Inc. · www.optimizely.com

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

The panel's verdict

Optimizely's Web and Feature Experimentation scores best where its documentation runs deepest. Data and integrations, the strongest column at 4-6, rests on warehouse connections to BigQuery, Snowflake, Redshift and Databricks documented with service-account, role and key setup detail and a warehouse-native analytics claim. Experimentation scope follows at 4-5, though several judges found that A/B, multi-page, feature and server-side testing appear as feature-grid copy with no documented SDKs behind them. The weak columns run low: performance impact sits at 0-1 with no public information found on snippet size, loading behaviour or Core Web Vitals; statistical rigour at 1-2 rests on one phrase — a 'Proprietary Stats Engine for results you can trust' — with no named method; consent and tracking at 1-2 reflects guidance aimed at the customer's own forms rather than the test script. Sovereignty is a uniform 3: EU contracting entities exist, transfers rest on the EU-US Data Privacy Framework, and a hashed user ID may be shared with ad networks. Scores tracked closely, the only spread wider than one point being data and integrations; no plan prices are published.

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Speaks for it

  • Warehouse connections to BigQuery, Snowflake, Amazon Redshift and Databricks are documented with service-account, role and JSON-key setup detail.
  • Warehouse-native analytics is claimed on the plans page for measuring outcomes such as revenue and retention on your own data.
  • The plans page lists A/B, multi-page, feature and server-side testing alongside real-time personalisation and audience targeting.
  • A data processing agreement and trust centre are published, with a Data Protection Officer contact listed.

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Held against it

  • We found no public information on the experiment snippet's size, loading behaviour, flicker handling or Core Web Vitals impact.
  • The only statistical statement captured is 'Proprietary Stats Engine for results you can trust', with no named method or sample-size guidance.
  • We found no public information on what the test script stores on a device, whether it runs before consent, or whether a cookieless mode exists.
  • We found no public information on documented SDKs, multivariate tests, mutually exclusive groups or holdouts behind the testing claims.
  • We found no public information on where visitor data is hosted or on named subprocessors, while transfers rest on the EU-US Data Privacy Framework.

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Best for

  • You already run BigQuery, Snowflake, Amazon Redshift or Databricks and want test outcomes measured against your own warehouse data.
  • You need A/B, multi-page, feature and server-side testing in one platform and will verify SDK and delivery mechanics with the vendor before signing.
  • Your team wants experimentation analytics unified with customer and product data in BigQuery to measure revenue and retention.

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Avoid if

  • You must document the statistical method, sample-size guidance or peeking protections to a regulator or your finance team before declaring a winner.
  • Your page-speed budget cannot absorb a third-party script whose weight and flicker behaviour you cannot verify before deployment.
  • Your DPO needs documented consent behaviour of the test script — what it stores on a device and whether it runs before the banner is answered — before rollout.
  • You need a documented API or visitor-level export to re-check winners outside the vendor's dashboard.

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The scores

Experiment types & delivery

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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 Growth Lead

The plans page claims A/B, multi-page, feature and server-side testing with real-time personalization and audience targeting, but that is feature-grid copy rather than documentation. The captured documentation covers consent forms and warehouse setup only, and we found no public information on SDKs for server-side work, multivariate tests, or a visual editor for experiments the team could use unaided. 2 1

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The E-Commerce Manager

The plans page lists A/B, multi-page, feature and server-side testing plus real-time personalisation and audience targeting — broad enough on paper for most of what I run. But that is a feature grid, and we found no public information on documented SDKs, multivariate tests, mutually exclusive groups, holdouts, or whether personalisation itself can be tested against a control, which is the proof I actually need before paying for it. 1 2

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The Product Engineer

The plans page lists A/B, multi-page, feature and server-side testing, a proprietary stats engine and real-time personalisation — but that is a feature grid, and the captured documentation gives me no SDK, no delivery detail and no server-side implementation to read. I score what I can verify, and here the grid claims more than the documentation shows. 1 2

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The CRO Consultant

The pricing page promises "A/B, multi-page, feature and server-side testing" with real-time personalisation and audience targeting, which claims more than a client-side-only tool. But this is a marketing grid, not documentation: we found no public information on server-side SDKs, multivariate tests, mutually exclusive groups or holdouts, so I score the claim rather than mechanics I can verify. 1 2

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The Data Protection Officer

The product pages advertise A/B, multi-page, feature and server-side testing with real-time personalisation and audience targeting, which is a solid middle position on this scale. Beyond that, we found no public information on documented SDKs, mutually exclusive experiment groups, holdouts, or edge delivery. 1 2

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The Skeptic

The plans page lists A/B, multi-page, feature and server-side testing with real-time personalisation and audience targeting, which is more than client-side splits. But every claim sits on a feature grid: I found no public information on documented SDKs, multivariate tests, mutually exclusive groups or holdouts, so the delivery mechanics cannot be verified from what was captured. 1 2

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Statistical method & guardrails

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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 Growth Lead

The only evidence is the phrase 'Proprietary Stats Engine for results you can trust', and we found no public information naming the method, giving sample-size or duration guidance, or addressing peeking and sample ratio mismatch. When finance asks where the uplift figure came from, 'proprietary' is not a defence I can take to the board. 2

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The E-Commerce Manager

The captured pages point to a 'Proprietary Stats Engine for results you can trust' without documenting the method, its assumptions, or any sample-size guidance. We found no public information on intervals, protection against stopping a test early, correction for multiple variants, or sample ratio mismatch detection. 2

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The Product Engineer

The only statistical statement anywhere is the plans page's "Proprietary Stats Engine for results you can trust"; we found no public information naming the method, sample-size or duration guidance, handling of peeking or multiple comparisons, or sample ratio mismatch detection. An engine I cannot see into deciding my winners is a claim, not a method. 2

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The CRO Consultant

The only statistics evidence we found is "Proprietary Stats Engine for results you can trust" — a brand name, with the method itself unnamed and nothing on sample size, peeking or sample ratio mismatch. I cannot defend a winner declaration to a client on trust language alone. 2

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The Data Protection Officer

The plans page promises a proprietary Stats Engine for results you can trust, and we found no public information naming the statistical method, giving sample-size or duration guidance, or warning against stopping a test early. As the person who has to certify a result to a regulator, I cannot even tell from these pages whether a Bayesian or frequentist model decides the winner. 2

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The Skeptic

The whole statistical story is one phrase on the plans page — "Proprietary Stats Engine for results you can trust" — a brand name where I need a method, and neither frequentist nor Bayesian is stated. I found no public information on sample-size or duration guidance, protection against peeking, corrections for multiple metrics or variants, or sample ratio mismatch detection. 2

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Snippet performance & flicker

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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 Growth Lead

We found no public information on script size, loading behaviour or flicker handling for the experimentation snippet. The only performance statement captured is high-performance content delivery on.NET Core in the CMS description, which speaks to content, not to the test script. 2

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The E-Commerce Manager

We found no public information on the test snippet's size, loading behaviour or flicker handling; the only performance statement on the captured pages concerns high-performance.NET Core delivery for the CMS, which is not the script sitting on my product page. No published figures exist for script weight, Core Web Vitals impact, or anti-flicker trade-offs. 2

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The Product Engineer

We found no public information on the snippet's weight, loading behaviour, flicker handling or Core Web Vitals impact — the captured pages say nothing measurable about the client-side script's cost to the page. For a script that runs on every visitor, that leaves me nothing to assess. 1 2

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The CRO Consultant

We found no public information on snippet weight, loading behaviour, flicker handling or any measured effect on Core Web Vitals. The only performance language on the captured pages concerns high-performance delivery of the CMS on.NET Core, which is a different product from the experiment snippet. 2

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The Data Protection Officer

We found no public information on script size, loading behaviour, flicker handling, or effects on Core Web Vitals anywhere in the captured pages. What I can see is marketing language about high performance delivery, which tells me nothing about what the snippet costs the page it tests. 1 2

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The Skeptic

I found no public information on snippet size, loading behaviour, flicker handling or Core Web Vitals impact on any captured page, including the homepage and plans page where such figures would sit. With no published measurement of any kind, this lands at the bottom of the scale. 1 2

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Analytics, data export & integrations

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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 Growth Lead

Warehouse connections are genuinely documented — BigQuery, Snowflake, Databricks and Redshift with setup detail, plus warehouse-native analytics claimed on the plans page — so I could check outcomes against revenue in my own data. But we found no public information on a documented API, export of visitor-level experiment data, or tag-manager integration, which limits independent verification. 6 7 2

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The E-Commerce Manager

Warehouse connectivity is genuinely documented — Snowflake, BigQuery, Databricks and Redshift, with BigQuery wired into Optimizely Analytics to measure revenue and retention on my own data — which is how I would verify a test result outside the vendor's dashboard. We found no public information on a documented API for reading results, visitor-level export, or tag-manager and analytics integrations. 2 6 7

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The Product Engineer

The strongest evidence in the set: documented warehouse connections to BigQuery, Snowflake, Databricks and Redshift with real setup detail — service accounts, custom roles, JSON keys — and warehouse-native analysis claimed on the plans page. But the documented flow is the customer's warehouse feeding Optimizely Analytics, and we found no public information on an API or on exporting visitor-level experiment results, which is what I need to re-check a winner in my own data. 2 6 7

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The CRO Consultant

Warehouse-native analysis is documented in real depth — BigQuery, Snowflake, Redshift and Databricks connections with service-account permissions and roles spelled out — and that is the check-the-result-in-your-own-data story I look for. We found no public information on a documented API, visitor-level export, or export of experiment results, so it stays short of the top level despite the strong warehouse coverage. 2 6 7

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The Data Protection Officer

Warehouse-native analytics with documented connections to Google BigQuery, Snowflake, Databricks and Amazon Redshift is the strongest part of this file, including the setup steps for querying the customer's own warehouse. However, we found no public information on visitor-level raw data export, a documented API with stated limits, or export of full historical experiment data for independent re-analysis. 2 6 7

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The Skeptic

Warehouse connections to BigQuery, Snowflake, Redshift and Databricks are documented with real setup detail — service accounts, custom roles, permissions — and the plans page claims warehouse-native analytics. But the documented direction is the customer's warehouse feeding Optimizely Analytics; I found no public information on a documented API, export of results, or visitor-level data leaving the platform for independent re-analysis, which is the direction that makes a result checkable. 6 7 2

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European sovereignty panel opinion

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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 Growth Lead

The vendor is Optimizely North America Inc. of New York with Optimizely AB in Sweden named as a contracting entity, and we found no public information on where visitor data is hosted or which named subprocessors process it — only broad categories. Transfers to the US are addressed through the EU-US Data Privacy Framework and a data processing agreement is published, but nothing in the captured pages places the experimentation data in the EU. 3 4

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The E-Commerce Manager

Which entity signs matters: the privacy notice names Optimizely North America Inc. and Optimizely AB, and the terms point to a German entity too, while residency and ownership of the vendor remain unknown. The pages list only categories of recipients rather than named subprocessors, and the EU-US Data Privacy Framework together with intra-group transfer language indicates visitor data can reach the US; a DPA is published, but we found no public information showing EU hosting of visitor data as standard. 3 4

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The Product Engineer

The contracting vendor is Optimizely North America Inc., with EU entities (Optimizely AB and a Berlin GmbH) in the group, the captured pages do not state hosting, and the privacy notice names only categories of recipients — payments, hosting, analytics, storage — rather than a subprocessor list. Transfers to the US rest on the Data Privacy Framework rather than EU processing of visitor data, so this sits at residency-as-an-arrangement with the subprocessor picture unpublished. 3 4

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The CRO Consultant

The vendor is Optimizely North America Inc with EU contracting entities available (Optimizely AB, and a Berlin-registered GmbH), the privacy notice relies on the EU-US Data Privacy Framework, and a hashed user ID may be shared with ad networks such as Google and Facebook. Data residency and ownership of visitor data are unstated, and recipients appear only as categories rather than a named subprocessor list — an EU entity on the contract is a different thing from EU processing of every visitor's behaviour. 3 4

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The Data Protection Officer

Multiple contracting entities are named, including Optimizely AB and a Berlin company, but the applicable entity depends on the deal, and we found no public information on where visitor data is processed or stored. The privacy notice lists only categories of recipients — hosting, analytics, storage — rather than a published subprocessor list naming the CDN, and transfers outside the EU rest on the EU-US Data Privacy Framework rather than EU processing. 3 4

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The Skeptic

The contracting entity varies by deal — Optimizely North America Inc., Optimizely AB, or Optimizely GmbH in Berlin — and nothing captured states where visitor data is hosted or processed. Subprocessors appear only as broad categories, the stated safeguard for transfers is the EU-US Data Privacy Framework, and a hashed user identifier may be shared with US-based networks such as Google and Facebook; a data processing agreement exists, but residency remains an open question. 3 4

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Pricing transparency not rated — the vendor publishes no price

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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 Growth Lead

There are no public prices at all — every plan is individually packaged through a sales conversation, so no annual cost is computable. The subscription terms do disclose that overage is billed at two times the usage-volume unit price, invoiced monthly in arrears, with twelve-month automatic renewal and ninety days' cancellation notice, but the unit price itself is not published. 2 4

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The E-Commerce Manager

The plans page puts every tier behind a contact form — 'Every Optimizely plan is individually packaged' — so we found no public prices at all. The terms do publish the machinery around the invoice: overage at 'two times (2x) Usage Volume unit price', twelve-month auto-renewal, non-refundable fees, no usage reduction during the term, and 120 days' notice of price increases — with no base price visible, my December-peak invoice cannot be computed from public pages. 2 4

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The Product Engineer

The plans page is explicit: "Every Optimizely plan is individually packaged. Tell us a bit about your digital needs, and we'll create a plan together." The terms do publish mechanics — overage fees at two times the usage unit price invoiced monthly in arrears, twelve-month auto-renewal, ninety-day non-renewal notice — but with no public tier prices or usage volume pricing, the invoice remains a sales conversation. 2 4

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The CRO Consultant

"Every Optimizely plan is individually packaged" through a contact form — we found no public prices, no traffic metric and no limits, so the invoice is unknowable before a sales conversation. The terms do publish real mechanics — overage fees at "two times (2x) Usage Volume unit price" invoiced monthly in arrears, twelve-month auto-renewal with ninety days' notice — but without a public unit price they help me assess risk, not budget a client's annual cost. 2 4

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The Data Protection Officer

The plans page states every plan is individually packaged through a contact form, so no tier price is public and an annual cost cannot be computed. The subscription terms do publish the mechanics that will surprise buyers — usage-volume overage at two times the unit price invoiced monthly in arrears, automatic twelve-month renewal, ninety-day cancellation notice — but mechanics without figures leave the invoice unknowable. 2 4

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The Skeptic

Every plan is "individually packaged" through a conversation, so no tier, traffic metric or limit is public and no annual invoice can be computed. The published terms do state pricing mechanics — overage at "two times (2x) Usage Volume unit price" invoiced monthly in arrears, automatic twelve-month renewal, ninety days' notice to cancel, no usage reduction during a term — but mechanics without prices still leave the cost unknowable. 2 4

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European sovereignty — proven facts

1 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 Not determined — uncited Report an error
Subprocessors Not determined — uncited 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 (7)

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

  1. 1 Vendor homepage www.optimizely.com Checked 22 Sep 2026 Details →
  2. 2 Pricing page www.optimizely.com Checked 22 Sep 2026 Details →
  3. 3 Privacy policy www.optimizely.com Checked 22 Sep 2026 Details →
  4. 4 Terms of service www.optimizely.com Checked 22 Sep 2026 Details →
  5. 5 Consent & visitor tracking — found from sitemap docs.optimizely.com Checked 1 Oct 2026 Details →
  6. 6 Analytics, data export & integrations — found from sitemap docs.optimizely.com Checked 1 Oct 2026 Details →
  7. 7 Analytics, data export & integrations — found from sitemap docs.optimizely.com Checked 1 Oct 2026 Details →