GrowthBook vs Statsig

GrowthBook

Feature-flag experiments, a visual editor, URL redirects and inline server-side tests run through 24+ SDKs across server, client, mobile and edge, with mutual exclusion via namespaces, holdouts, sticky bucketing and a Cloudflare edge app that evaluates flags and rewrites variations before HTML reaches the browser. We found no public information on a personalisation capability that can itself be tested against a control, a documented experiment lifecycle from hypothesis to archived result, or a searchable library of past results.

Statsig

The captured pages show client-side testing through a no-code editor and server-side delivery through open-source SDKs for over thirty languages, with layers and holdouts for managing experiment interactions and attribute- and segment-based targeting. Feature flags are described as linked directly to product data, which supports one shared audience and metric model. We found no public information on edge or CDN delivery, multivariate or multi-page tests, or a documented lifecycle from hypothesis to archived result.

GrowthBook

Both engines are documented by name — Bayesian by default with an improper uninformative prior and a switchable proper prior, frequentist two-sample t-tests for relative percent change — alongside Holm-Bonferroni and Benjamini-Hochberg corrections across goal metrics and variations, sample ratio mismatch detection, CUPED on both engines, guardrail metrics, minimum-data checks against reading results too early, and the whole implementation open source under MIT so a result can be reproduced. The captured pages do note that adjusted p-values are available in the interface and CSV downloads but not through the API.

Statsig

The methods are named on the pricing page: sequential testing, CUPED, Bonferroni and Benjamini-Hochberg corrections, and winsorization, and power analysis appears in the platform capability list. That goes well beyond naming a school of statistics. We found no public information on sample ratio mismatch detection, guardrail metrics that stop a harmful test, or a methodology published in enough detail to reproduce a result.

GrowthBook

The gbuuid cookie is named, first-party and configurable, assignment is documented as stateless hashing that needs no cookie, an environment variable delays writing the cookie until a consent event fires from the page, and sticky bucketing is documented as consent-gated — yet from these pages I still cannot answer whether the exposure tracking callback or the payload fetch waits for the consent banner, and we found no public information on consent-management-platform integrations, cookie lifetimes, IP anonymisation, or guidance on the legal basis for testing in the EU. The privacy notice further states that DNT signals are not responded to or honored.

Statsig

The only statement we found about what is stored on the device is Amplitude's general list of cookie categories — essential, performance, functionality, advertising — and we found no public information listing Statsig's storage keys, their lifetimes, or IP anonymisation. Critically, we found no public information on whether the test script may run before the consent banner is answered, on a consent-pending mode, on a cookieless mode, or on integration with consent management platforms, so the §25 TDDDG question a German buyer must answer is unaddressed on these pages.

GrowthBook

The documentation is candid that the edge app's default is a blocking API call that delays page delivery, and publishes two elimination paths — a webhook push model to an edge key-value store and a just-in-time payload cache — plus CDN delivery of SDK payloads, a proxy server with caching for self-hosters, and edge evaluation that runs visual and redirect experiments into the HTML before it ships to cut flicker. We found no public information on absolute script size figures or measured Core Web Vitals impact.

Statsig

The pages publish figures for the vendor's own infrastructure — post-init evaluation latency under 1ms and 99.99% uptime for API and console — not the cost the snippet imposes on the customer's page. We found no public information on script size, loading behaviour, flicker handling, a self-hosting option, or any effect on Core Web Vitals.

GrowthBook

Warehouse-native is the core promise: metrics defined once in SQL and computed in the customer's own Snowflake, BigQuery, Databricks or Redshift with every query visible and no PII leaving the warehouse, alongside a full REST API covering experiments, per-experiment results, fact tables and saved groups, and named integrations including Segment.io, GA4, Google Tag Manager, Slack and Shopify. We found no public information on stated API rate limits or streaming export of raw event data.

Statsig

Warehouse-native deployment, warehouse ingestion and data warehouse imports, outgoing data integrations, and a data export API are all listed, which lets results be checked against the customer's own data. We found no public information on visitor-level raw export formats, a CDP integration for audiences, or documented API rate limits.

GrowthBook

The contracting entity is GrowthBook, Inc. of Anaheim, California, the privacy notice states personal information is held and processed in the United States by consent-through-use, hosting is on AWS, and I found no public information on an EU residency option for the cloud service, on a published subprocessor list that includes the CDN at cdn.growthbook.io, or on server regions for the named AI sub-processors (Anthropic, Google, OpenAI, xAI) and the ClickHouse managed warehouse. Self-hosted, air-gapped deployment is the only documented path that keeps data on infrastructure the customer controls.

Statsig

The contracting entities are American — Statsig in Bellevue under Washington law, with the privacy notice resolving to Amplitude in San Francisco — and the notice states personal data may be transferred to the United States. EU hosting appears only inside the warehouse-native enterprise option, so visitor data is not processed in the EU as standard. We found no public information on a Statsig-specific subprocessor list naming the CDN; Google and Stripe appear only incidentally in Amplitude's site-wide notice, though standard contractual clauses are mentioned as a possible safeguard.

GrowthBook

Starter is free with up to 3 users and 1 project, Pro is "$40 / seat / month" with up to 30 users and 3 projects, and the usage-based pieces carry published limits and overage — managed warehouse events 1M/mo and 2M/mo "then $30/M", CDN requests 1M/mo and 2M/mo "then $10/M", CDN bandwidth 5GB/mo and 20GB/mo "then $1/GB" — with unlimited feature flags, experiments and traffic. Enterprise is priced only as Custom, and we found no public information on minimum term or VAT treatment.

Statsig

The free and Pro tiers are fully priced with the traffic metric defined: 2M events per month free, then $150 /mo with 5M events included and $0.05 per 1K events thereafter, overages billed in the next period, dedup windows documented, and no charge for exposures on 0% or 100% rollouts. The Enterprise tier is priced only as "Custom" with event- or experiment-based contracts, seats are unpriced, and taxes are simply the customer's responsibility, so the full annual cost is not computable at every tier.