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Testing · head to head

GrowthBook vs TestNG

GrowthBook logo

GrowthBook

Testing

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

From
Free
Rated
-
Full reviewWebsite
TestNG logo

TestNG

Testing

Java testing framework created by Cedric Beust, still actively maintained but effectively a single-lead project

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: 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.; TestNG maintainership is concentrated around creator Cedric Beust rather than a broad team or foundation, which is a real continuity risk compared to JUnit's independent team or Jest's foundation backing.
  • They diverge on capability: GrowthBook covers Feature flags, TestNG covers Test dependencies.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which GrowthBook and TestNG actually diverge.

Attributes where GrowthBook and TestNG differ
AttributeGrowthBookTestNG
Pricing modelPer user per monthOpen source, no licence fee
PlatformsWeb, Self-hosted, DockerLinux, macOS, Windows

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Testing).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in GrowthBook

  • Feature flags
  • Warehouse-native analysis
  • Reusable metric definitions
  • Bayesian and frequentist engines
  • CUPED variance reduction
  • Visual editor
  • Self-hosting
  • Guardrail metrics

Only in TestNG

  • Test dependencies
  • XML suite configuration
  • Native parallel execution
  • Data providers
  • Grouping
  • Flexible reporting

What people use each for

The jobs each tool is most often brought in to do.

GrowthBook

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

TestNG

  • A Java integration test suite that needs to skip dependent tests automatically when a prerequisite test failsnot GrowthBook
  • A team wanting XML-based suite configuration to manage large, grouped test suites without touching code for each runnot GrowthBook
  • A project needing native parallel test execution at the class or method level without adding a separate pluginnot GrowthBook
  • A Selenium-based UI test suite that uses TestNG as the underlying runner for grouping and parallelisationnot GrowthBook

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

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.

TestNG

  • Maintainership is concentrated around creator Cedric Beust rather than a broad team or foundation, which is a real continuity risk compared to JUnit's independent team or Jest's foundation backing.
  • It is a smaller ecosystem than JUnit, so fewer third-party integrations, tutorials and Stack Overflow answers exist for edge cases.
  • XML-based suite configuration, while powerful, is an extra file and syntax to maintain alongside the codebase, which some teams find adds friction JUnit's more code-centric model avoids.
  • There is no commercial support tier or vendor relationship of any kind, unlike JUnit's OpenElements arrangement, so an enterprise wanting a support contract has no route to buy one.
  • Release cadence, while active, is slower and less frequent than JUnit 5's, since it depends on a much smaller pool of active maintainers.

Pricing, plan by plan

GrowthBook

Free
  • 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/month
    • Per seat, up to 50 users
    • 3 projects
    • CDN overage at $10 per million requests beyond the included allowance
  • Enterprise$undefined/year
    • Unlimited users and projects
    • SSO, audit logs and advanced permissions
    • Available on cloud or self-hosted

TestNG

Free
  • TestNGFree
    • Full functionality, no usage limits
    • Community support via GitHub
    • No commercial support tier exists

Which should you pick?

Choose GrowthBook if

  • You need feature flags.
  • You want to start without paying.
  • You work on Web, Self-hosted, Docker.
  • You also want warehouse-native analysis.
GrowthBook review

Choose TestNG if

  • You need test dependencies.
  • You want to start without paying.
  • You work on Linux, macOS, Windows.
  • You also want xml suite configuration.
TestNG review

Questions people ask

Is GrowthBook or TestNG better?
Neither clearly leads. GrowthBook starts at Free and TestNG at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, GrowthBook or TestNG?
GrowthBook starts at Free and TestNG at Free.
Does GrowthBook or TestNG run on more platforms?
GrowthBook runs on Web, Self-hosted, Docker. TestNG runs on Linux, macOS, Windows.
Can I use GrowthBook for free?
Both have a free tier, so you can try either at no cost before committing.
What is GrowthBook best used for?
GrowthBook is most often used 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. Of those, an engineering team that wants feature flags without a per-monthly-active-user bill that grows with product success and a data team that needs experiment results to reconcile exactly with the metrics reported in its bi tool are not what TestNG is typically brought in for.
What can GrowthBook do that TestNG cannot?
GrowthBook covers Feature flags, Warehouse-native analysis, Reusable metric definitions, Bayesian and frequentist engines. TestNG covers Test dependencies, XML suite configuration, Native parallel execution, Data providers.

Answered from the vendors’ own pages

GrowthBook: 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.

TestNG: Is TestNG still actively maintained in 2026?

Yes, it continues to receive releases in its 7.x line with support for current Java versions, though maintenance is concentrated around a small team led by its creator.

GrowthBook: 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.

TestNG: What does TestNG offer that JUnit does not?

Native test dependencies, XML-based suite configuration and built-in parallel execution without needing external plugins, all of which JUnit users typically add via separate libraries.

GrowthBook: 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.

TestNG: Is there a commercial support option for TestNG?

No, unlike JUnit there is no commercial support arrangement; support is purely community-based through GitHub.

GrowthBook: 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.

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