Optimizely vs VWO

Optimizely

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.

VWO

The pricing page shows a visual editor with WYSIWYG and code editing, A/B/n, split and multivariate tests, advanced targeting and triggers beyond plain URLs, and single-page-application support, with mutually exclusive groups at the enterprise tier — most of what my team needs day to day. However, I found no public information on documented SDKs for server-side delivery, holdouts or edge delivery, so the server-side half rests on a module name rather than documentation.

Optimizely

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.

VWO

Guardrail metrics, sample ratio mismatch detection and multi-arm bandit campaigns are listed, which is more rigour tooling than most feature grids show. But I found no public information naming the statistical method, showing confidence or credible intervals, or offering a sample-size or duration calculator — exactly what finance will ask me to produce when the uplift is challenged.

Optimizely

The consent documentation tells customers they must obtain affirmative, per-purpose consent and store it, framing consent as the customer's obligation, and we found no public information on what the test script stores on the device or whether it runs before consent. No cookie list, consent-pending mode or cookieless option appears in the captured pages, which is a serious exposure for a German rollout.

VWO

The privacy policy states outright that it applies only to Wingify's customers and not to the visitors of my website, and an opt-out for end users plus an available data processing addendum are mentioned. Beyond that I found no public information on what the test script stores on a device, on its behaviour before consent is given, or on a cookieless mode — a real problem for a German team under TDDDG.

Optimizely

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.

VWO

Self-hosting appears on the enterprise tier and the privacy policy describes CDN delivery from ten locations on named infrastructure. But I found no published figures for script size, asynchronous loading or flicker handling, and no public information on the effect on Core Web Vitals.

Optimizely

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.

VWO

An integrations section exists, pull-based integrations ship at the Pro tier, API access is gated to Enterprise, and Data Studio is a paid add-on. I found no public information on API documentation, export of visitor-level results or warehouse-native analysis, so a result could not be re-checked in my own data as far as these pages show.

Optimizely

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.

VWO

The contracting entity is Wingify Software Pvt. Ltd. of Delhi, and the privacy policy states all customer data is centrally stored in Washington DC and Dallas, with standard contractual clauses and an Article 27 representative in Vienna as safeguards. I found no public information on an EU residency option or a published subprocessor list, and the visitor data the script records flows to US-hosted infrastructure.

Optimizely

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.

VWO

The pricing page names Growth, Pro and Enterprise tiers plus add-ons and even a shared-MTU-quota question, but states "No fixed plans. Just a custom proposal built around your goals and scope", and no price figure appears anywhere. A free trial exists, but the invoice is a sales conversation, and I cannot defend a budget line I cannot compute.