GrowthBook

Open source feature flags and A/B testing that run experiment analysis inside your own data warehouse

As of 31 August 2026, GrowthBook has a free plan and paid plans start at $40/month. GrowthBook does feature flagging and experimentation, but it computes results by querying your warehouse rather than by collecting events itself. Softwr lists it under Testing. GrowthBook is available on Web, Self-hosted.

Visit siteVisit GrowthBook

Overview

What GrowthBook does

GrowthBook is an MIT-licensed platform combining feature flags with a statistics engine for A/B tests. Flags evaluate in SDKs across a long list of languages, and when a test finishes GrowthBook writes SQL against Snowflake, BigQuery, Redshift, Databricks, ClickHouse or Postgres to compute the result. Metrics are defined once as SQL and reused across experiments, and the engine supports both Bayesian and frequentist analysis with sequential testing and CUPED variance reduction. The commercial consequence of warehouse-native analysis is that you are not paying a vendor per tracked event or per monthly active user for data you already store. It also means the numbers in GrowthBook reconcile with the numbers in your BI tool, because they came from the same tables, which removes an argument that experimentation programmes routinely lose. Self-hosting is a genuine option, not a crippled tier: the open source build has unlimited users, unlimited flags and unlimited experiments on one project. Users are engineering and data teams that already run a warehouse. The trade offs are that you need that warehouse and someone fluent in SQL to define metrics correctly, cloud Pro is $40 per seat per month with usage overages for CDN requests and bandwidth on top, and the statistics engine assumes you understand what you are configuring. It is a tool for teams with data competence, not a turnkey optimisation product for a marketing department.

What people use it for

An engineering team that wants feature flags without a per-monthly-active-user bill that grows with product success
A data team that needs experiment results to reconcile exactly with the metrics reported in its BI tool
A company with data residency or privacy constraints that cannot send user-level event data to a third-party vendor
Running long-tail experiments where sequential testing and CUPED shorten the time to a decision on low-traffic surfaces

Where it falls short

Concrete and checkable, so you can decide whether any of them matter to you. This is the half of a review a vendor will not write about GrowthBook.

Warehouse-native analysis is only an advantage if you have a warehouse with clean event data in it; without one, GrowthBook has nothing to compute against and you are back to buying an event-collecting platform.
Metrics are SQL, so a marketing or product team without data engineering support cannot define or fix them, and a badly written metric silently produces a confident wrong answer.
Cloud Pro bills per seat and then adds CDN request and bandwidth overages, so a high-traffic site can find the variable component exceeds the seat cost it budgeted for.
Self-hosting means you own the Mongo database, the SDK endpoint availability and the upgrade path, and a flag service that is down is a production incident, not an analytics inconvenience.
The statistics engine exposes real choices, Bayesian versus frequentist, sequential testing, variance reduction, and the tool will not stop a team that configures them wrongly, so it rewards statistical literacy and punishes its absence.

Cross-shopped

What people choose instead of GrowthBook

Each pairing was judged by two reviewers asking whether a buyer would genuinely weigh the two against each other. The ones that failed were deleted rather than published.

GrowthBookvs
LaunchDarkly
LaunchDarkly: If you want a mature commercial flag platform with enterprise governance and will pay per monthly active user for it
GrowthBookvs
Statsig
Statsig: If you want warehouse-native experimentation with a larger built-in analytics layer and a hosted-first model
GrowthBookvs
Unleash
Unleash: If you only need open source feature flags and have no interest in the experimentation statistics

Pricing

What GrowthBook costs

Taken from the vendor's own pricing page. Prices move, so check before you buy.

Open source (self-hosted)

Free

Unlimited users, feature flags and experiments
One project
MIT licensed, you run the infrastructure

Starter (cloud)

Free

Up to 3 users
1 project
Unlimited flags, experiments and traffic

Pro (cloud)

$40 /mo

Per seat, up to 50 users
3 projects
CDN overage at $10 per million requests beyond the included allowance
Bandwidth overage at $1 per GB beyond the included allowance

Enterprise

On request

Unlimited users and projects
SSO, audit logs and advanced permissions
Available on cloud or self-hosted
Quoted individually

Capabilities

Features

Feature flags
Percentage rollouts, targeting rules and kill switches across many SDK languages
Warehouse-native analysis
Experiment results computed by SQL against your own data, not a vendor event store
Reusable metric definitions
Metrics written once in SQL and applied across every experiment
Bayesian and frequentist engines
Choose the statistical framework, with sequential testing available
CUPED variance reduction
Uses pre-experiment data to tighten confidence intervals and shorten tests
Visual editor
No-code changes for simple front-end tests without a deploy
Self-hosting
Full open source deployment with unlimited users, flags and experiments
Guardrail metrics
Automatic monitoring of metrics a test must not damage

Answered, with sources

Questions people ask

Each answer names the page it came from, so you can check it rather than take our word for it.

Is the self-hosted version actually usable, or crippled?

It is genuinely usable: unlimited users, flags and experiments on one project under an MIT licence. The paid tiers add multiple projects, SSO, audit logs and support.

Do I need a data warehouse?

For experiment analysis, effectively yes. Feature flagging works without one, but the reason to choose GrowthBook over a flag-only tool is the warehouse-native statistics.

How does the cost compare with LaunchDarkly or Optimizely?

GrowthBook charges per seat rather than per monthly active user or per tracked event, so cost stops scaling with traffic. At high volume that difference is large.

Does it support mobile and server-side flags?

Yes, there are SDKs across JavaScript, React, Python, Go, Ruby, PHP, Java, Kotlin, Swift and more, covering client, server and mobile evaluation.

Keep looking

Where to go from GrowthBook

Best Testing software for

Compare GrowthBook with

Other Testing software

Eppo
Warehouse-native experimentation and feature flagging, now sold as Datadog Experiments
Pricing on request13 researched notes
Kameleoon
A/B testing and feature experimentation with a hybrid client and server-side engine
Pricing on request12 researched notes
Split
Feature flags tied to a metrics pipeline that attributes production impact to each release, now Harness FME
Pricing on request13 researched notes
Qase
Test case management with an API first design and a free tier for small teams
Free plan10 researched notes
Appium
Open source mobile automation framework hosted under the OpenJS Foundation with copyright assigned to the foundation
Open source11 researched notes
Detox
Open source end-to-end testing framework for React Native apps, built and maintained by Wix
Open source11 researched notes
Insomnia
REST and GraphQL API client for development and testing
Free plan12 researched notes
GitHub Actions
Automate your software workflows
Free plan17 researched notes
Robot Framework
Keyword-driven test automation framework governed by a member-funded foundation
Open source13 researched notes
TestRail
Test case management priced per user, owned by the Idera software group
From $38/mo12 researched notes
Xray Test Management
Native test management for Jira, licensed per Jira user rather than per tester
11 researched notes
Cucumber
Behaviour-driven development testing framework that returned to community ownership after nine years under SmartBear
Open source11 researched notes
k6
Load testing tool with JavaScript tests on a Go runtime, now owned by Grafana Labs
Open source12 researched notes
mabl
Low-code browser and API test automation with hosted runners and self-healing selectors
Pricing on request11 researched notes
Eppo
Warehouse-native experimentation and feature flagging, now sold as Datadog Experiments
Pricing on request13 researched notes
Kameleoon
A/B testing and feature experimentation with a hybrid client and server-side engine
Pricing on request12 researched notes
WebdriverIO
Open source Node.js browser and mobile automation framework, governed under the OpenJS Foundation with Sauce Labs as a premium sponsor
Open source11 researched notes
Detox
Open source end-to-end testing framework for React Native apps, built and maintained by Wix
Open source11 researched notes

Softwr does not host reviews and shows no star rating for GrowthBook, because a rating we did not collect is not ours to publish. What is here is the pricing and platform detail from the vendor’s own pages, limitations we could state concretely, and alternatives a reviewer confirmed people weigh against it. Tell us if any of it is wrong.

Best Testing software alternatives

View all Testing software