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Testing · head to head

GrowthBook vs Kong Gateway

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
Kong Gateway logo

Kong Gateway

APIs

Open-source and cloud API gateway for managing microservices traffic

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.; Kong Gateway the free open-source gateway lacks the analytics, portals, and support of the paid Konnect tiers.
  • They diverge on capability: GrowthBook covers Feature flags, Kong Gateway covers API request routing.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which GrowthBook and Kong Gateway actually diverge.

Attributes where GrowthBook and Kong Gateway differ
AttributeGrowthBookKong Gateway
Pricing modelPer user per monthfreemium
PlatformsWeb, Self-hosted, Dockerweb, linux, api
CategoryTestingAPIs
FoundedUnknown2017

Identical on both: starting price (Free), free tier (Yes), 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 Kong Gateway

  • API request routing
  • Plugin ecosystem
  • Developer portals
  • AI Gateway
  • Analytics and observability
  • SSO and audit logs

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

Kong Gateway

  • Routing and securing traffic across microservicesnot GrowthBook
  • Publishing internal or external developer portalsnot GrowthBook
  • Managing rate limits and authentication at the API edgenot GrowthBook
  • Gateway-level routing to multiple LLM providersnot 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.

Kong Gateway

  • The free open-source gateway lacks the analytics, portals, and support of the paid Konnect tiers.
  • Plus tier caps API requests at 1M/month before incurring per-million overage charges.
  • Enterprise pricing is custom and not published, making budgeting harder without sales contact.
  • Configuration and plugin management can require significant operational expertise to run at scale.

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

Kong Gateway

Free
  • Free TrialFree
    • 30-day enterprise functionality trial
    • Unlimited gateways
    • 30-day analytics retention
  • Plus$undefined/month
    • Up to 5 serverless, 2 hybrid, 2 dedicated cloud gateways
    • 1M API requests/month included
    • Up to 2 developer portals
  • Enterprise$undefined/month
    • Unlimited hybrid and dedicated cloud gateways
    • Unlimited developer portals
    • SSO and audit logs

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 Kong Gateway if

  • You need api request routing.
  • You want to start without paying.
  • You work on web, linux, api.
  • You also want plugin ecosystem.
Kong Gateway review

Questions people ask

Is GrowthBook or Kong Gateway better?
Neither clearly leads. GrowthBook starts at Free and Kong Gateway at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, GrowthBook or Kong Gateway?
GrowthBook starts at Free and Kong Gateway at Free.
Does GrowthBook or Kong Gateway run on more platforms?
GrowthBook runs on Web, Self-hosted, Docker. Kong Gateway runs on web, linux, api.
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 Kong Gateway is typically brought in for.
What can GrowthBook do that Kong Gateway cannot?
GrowthBook covers Feature flags, Warehouse-native analysis, Reusable metric definitions, Bayesian and frequentist engines. Kong Gateway covers API request routing, Plugin ecosystem, Developer portals, AI Gateway.

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.

Kong Gateway: Is Kong Gateway free?

Kong's core gateway is open source and free to self-host. Kong Konnect, the managed cloud platform, offers a 30-day free trial before moving to paid Plus or custom Enterprise 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.

Kong Gateway: How is usage metered on the Plus plan?

The Plus plan includes 1M API requests per month, with additional usage billed at $200 per extra 1 million requests up to a 10M/month cap, plus per-gateway and per-LLM-model charges.

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.

Kong Gateway: What support is included?

Plus includes email support with a 2-business-day SLA, while Enterprise adds dedicated success managers and professional services.

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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