Methodology
How this index is made
The reader we rank for is an online business, a merchant or the agency working for them, asking one question: which A/B testing tool will deliver measurable revenue impact at a defensible cost? We do not rank for feature-count, funding news or brand size.
Evidence rules
- Every factual claim links to a source we actually loaded, with an access date. No search-snippet facts.
- Where a vendor’s own pages contradict each other (it happens more than you would think), we say so instead of picking a side.
- What we could not verify is labeled unverified, and never rated as if it existed.
- Review-platform scores are only cited where we could load the page ourselves; several platforms block automated access, and we do not launder snippets into facts.
Ranking weights
| 30% | Consent handling and behaviour before consent Consent-manager integrations, documented consent modes, Do Not Track, and whether the tool can run with no device storage at all until consent arrives. Weighted first because this is where European supervisory authorities enforce most often. |
| 25% | Contract and data-subject rights A data processing agreement under Article 28(3) you can read today, a subprocessor annex that names each vendor’s entity, location and transfer mechanism, and export and erasure paths that actually execute. |
| 20% | Data minimisation and identifier hygiene IP handling, fingerprinting, cookie versus localStorage, identifier lifetime, and whether a no-storage mode exists. |
| 15% | Data residency and hosting transparency Where visitor data is stored, whether the region is named and verifiable, and the transfer mechanism. Weighted below consent and contract because an adequacy decision or standard contractual clauses can make a non-German location lawful, while a missing legal basis is not cured by any location. |
| 10% | Compliance program and independent attestation A managed control program, and ISO 27001 or SOC 2 reports where they exist. Weighted last because a certificate evidences a process, not lawful processing of your visitors’ data. |
Updates
Facts are re-checked monthly; the full ranking is re-evaluated quarterly. Each page carries its last-reviewed date. Current edition: 2026-09-01.
Independence & disclosure
This site is operated by the company named in the imprint. We link to vendors directly and use no affiliate links. If a ranked vendor relationship exists, the imprint is the authoritative disclosure.