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Testing · head to head

GrowthBook vs Optimizely

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
Optimizely logo

Optimizely

Marketing

Digital experience optimization

From
$10000/year
Rated
-
Full reviewWebsite

The short version

  • Only GrowthBook has a free tier, so it costs nothing to try first.
  • 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.; Optimizely no pricing is published and no minimum is stated
  • They diverge on capability: GrowthBook covers Feature flags, Optimizely covers A/B testing.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which GrowthBook and Optimizely actually diverge.

Attributes where GrowthBook and Optimizely differ
AttributeGrowthBookOptimizely
Starting priceFree$10000/year
Pricing modelPer user per monthquote
Free tierYesNo
PlatformsWeb, Self-hosted, DockerWeb, Mobile
CategoryTestingMarketing
FoundedUnknown2010

Identical on both: user rating (Not yet rated).

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 Optimizely

  • A/B testing
  • Multivariate testing
  • Personalization
  • Feature management
  • Analytics
  • Google Analytics
  • Adobe Analytics
  • SOC2

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 Optimizely
  • A data team that needs experiment results to reconcile exactly with the metrics reported in its BI toolnot Optimizely
  • A company with data residency or privacy constraints that cannot send user-level event data to a third-party vendornot Optimizely
  • Running long-tail experiments where sequential testing and CUPED shorten the time to a decision on low-traffic surfacesnot Optimizely

Optimizely

  • A/B testing and experimentation across web and product experiencesnot GrowthBook
  • Feature flagging and personalisation for digital productsnot 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.

Optimizely

  • No pricing is published and no minimum is stated
  • Every plan is individually packaged, so no two quotes are necessarily comparable
  • Reaching a figure requires a demo or sales conversation

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

Optimizely

$10000/year
  • Enterprise$undefined/year
    • A/B testing
    • Personalization
    • Feature management

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 Optimizely if

  • You need a/b testing.
  • You work on Web, Mobile.
  • You also want multivariate testing.
Optimizely review

Questions people ask

Is GrowthBook or Optimizely better?
Neither clearly leads. GrowthBook starts at Free and Optimizely at $10000/year, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, GrowthBook or Optimizely?
GrowthBook has a free tier; the other does not. Paid plans start at Free for GrowthBook and $10000/year for Optimizely.
Does GrowthBook or Optimizely run on more platforms?
GrowthBook runs on Web, Self-hosted, Docker. Optimizely runs on Web, Mobile.
Can I use GrowthBook for free?
Yes. GrowthBook has a free tier, so you can try it without paying. Optimizely starts at $10000/year.
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 Optimizely is typically brought in for.
What can GrowthBook do that Optimizely cannot?
GrowthBook covers Feature flags, Warehouse-native analysis, Reusable metric definitions, Bayesian and frequentist engines. Optimizely covers A/B testing, Multivariate testing, Personalization, Feature management.

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.

Optimizely: How much does Optimizely cost?

Optimizely does not publish pricing rates. The company states that every plan is individually packaged based on specific customer needs. Interested customers must request a demo or contact the sales team to receive customized pricing.

Source
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.

Optimizely: What is the pricing model for Optimizely?

Optimizely uses a custom enterprise pricing model rather than published rate cards. Pricing is determined through direct consultation with the sales team based on the customer's digital needs and feature requirements.

Source
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.

Optimizely: Is there a free trial of Optimizely?

Optimizely does not specify free trial availability on its website. Customers interested in exploring the platform are directed to request a demo through the company's website to discuss trial options.

Source
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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