GrowthBook vs Statsig

GrowthBook

Feature-flag experiments, a visual editor, URL redirects and even custom assignment from third-party systems all feed one results model, with namespaces for mutually exclusive tests, holdouts, sticky bucketing and multivariate, sequential and bandit test types documented. Edge delivery on Cloudflare Workers is documented in detail, and 24+ SDKs cover server, client, mobile and edge. We found no public information on personalisation that can itself be tested against a control, which keeps this just under the top band.

Statsig

Feature flags, layers for mutually exclusive experiments, holdouts, a no-code editor and a shared metric model with product analytics and session replay, plus 30+ open-source SDKs for server-side delivery, take this well past a basic split test. We found no public information on edge or CDN delivery or on personalisation that can itself be tested against a control, which is what separates this from the top tier.

GrowthBook

Both Bayesian and frequentist engines are documented down to default priors, two-sample t-tests and correction families (Holm-Bonferroni and Benjamini-Hochberg), with SRM detection, CUPED, guardrail metrics, minimum-data checks against reading 5-vs-2 results, and suspicious-uplift and multiple-exposure alerts. Analysis runs in visible SQL on the customer's own warehouse with only aggregates accessed, and the implementation is open source under MIT, so a client's data team can audit a result end to end. Corrections apply only to the frequentist engine and adjusted p-values export to CSV but not the API — minor caveats on an otherwise reproducible setup.

Statsig

Sequential testing, CUPED, Winsorization, Bonferroni and Benjamini-Hochberg corrections are all named, plus power analysis in the platform list, so the peeking and multiple-comparison risks I brief clients on are addressed explicitly. We found no public information on sample ratio mismatch detection or guardrail metrics that can stop a harmful test, and the methods appear as feature bullets rather than documented assumptions.

GrowthBook

The gbuuid identifier is a first-party cookie whose persistence can be held until consent via a documented setting and a page event, assignment itself is stateless hashing that needs no cookie, and sticky bucketing can be gated per user on consent having been given. For a DPO sign-off I still miss the rest: we found no public information on consent-management-platform integrations, a published cookie and storage list with lifetimes, IP anonymisation, or guidance on the legal basis for testing in the EU.

Statsig

The only consent-relevant material is Amplitude's site-wide privacy notice, which lists cookie categories and legal bases but nothing Statsig-specific about the test script. We found no public information on what the script does before consent is given, no consent-management integration, no published list of storage keys with lifetimes and no mapping to §25 TDDDG — this is not something I could hand a client's DPO.

GrowthBook

The documentation is unusually honest that the Edge App's default mode makes a blocking API call on every request, and spells out the fixes: a KV push model or just-in-time payload cache to eliminate it, plus edge-rendered visual and redirect experiments that cut flicker before HTML ships. Self-hosting with your own CDN or the Proxy server is documented, and the SDKs are claimed 50% smaller with zero network calls. We found no published figures for script weight or Core Web Vitals impact, only relative claims.

Statsig

The only published figure is post-init evaluation latency under 1ms for the SDK, which says nothing about what the snippet costs the client's page. We found no public information on script size, anti-flicker handling, impact on Core Web Vitals, or a self-hosting option for the script.

GrowthBook

Warehouse-native is the architecture, not a connector: metrics are defined in SQL and computed on Snowflake, BigQuery, Databricks or Redshift with no PII leaving the warehouse, every query is visible, and a versioned REST API includes a per-experiment results endpoint for pulling analysis into our own reporting. Results including adjusted p-values export to CSV, and native integrations cover Slack, Datadog, Shopify, WordPress and more. We found no published API rate limits and no CDP integration for audience syncing, which keeps it a notch below fully self-serve.

Statsig

Warehouse-native deployment, warehouse ingestion and a data export API are published, which matters to me because a result can be checked in the client's own data. The outgoing data integrations sit on the enterprise tier, and we found no public information on CDP-based audiences or stated API limits.

GrowthBook

GrowthBook, Inc. of Anaheim, California is the contracting entity, cloud hosting is stated as AWS in the United States, the privacy notice asks users to consent to transfer and processing in the United States, and the terms say the website is for use only by persons located in the United States. US AI providers are named as subprocessors for optional features, but we found no public information on a published subprocessor list, EU data residency, or a transfer safeguard such as adequacy or standard contractual clauses. Self-hosting air-gapped, where no data leaves the customer's system, is the only documented path that keeps visitor data off US infrastructure.

Statsig

The contracting entities are Statsig, LLC of Bellevue and Amplitude, Inc. of San Francisco under Washington law, and the privacy notice states personal data may be transferred to the United States with standard contractual clauses as safeguard. EU hosting appears as a warehouse-native feature on the pricing page, but the captured pages give different signals on residency and we found no published Statsig subprocessor list or DPA covering the visitor data the script collects.

GrowthBook

The seat model is public and computable: Starter free with one project and up to three users, Pro at $40 per seat per month up to 30 users and three projects, with published overage rates for managed warehouse events ($30 per million above the tier), CDN requests ($10 per million) and CDN bandwidth ($1 per GB) — plus unlimited traffic and unlimited experiments on every tier. The traffic meter here is events and CDN usage rather than monthly tracked users, which I can still estimate before a contract. Enterprise is custom-priced, and we found no public information on minimum term or VAT treatment.

Statsig

The Developer and Pro tiers are fully public — free with 2M events per month, $150 /mo including 5M events then $0.05 per 1K events, with exposure dedup windows and no charge for 0 or 100% roll-outs — so I can estimate an invoice before the contract, though each Pro subscription covers one project only. VAT treatment and renewal terms are stated in the terms, but the enterprise tier carrying warehouse native and SSO is Custom pricing, which keeps it short of fully computable.