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ConfigCat vs Preact

ConfigCat logo

ConfigCat

Developer Tools

Feature flag service priced per flag and environment with unlimited seats and unlimited monthly active users

From
Free
Free plan
Yes
Full reviewWebsite
Preact logo

Preact

Web Development

3kB alternative to React with the same modern API

From
Free
Free plan
Yes
Full reviewWebsite

The short version

  • Each has a real cost: ConfigCat there is no experimentation or statistical analysis engine, so teams wanting real A/B tests with significance testing must buy and integrate a separate analytics or experimentation product.; Preact compatibility through preact/compat is good but not total, and some React libraries break in ways that are hard to diagnose
  • They diverge on capability: ConfigCat covers Feature flags and configuration, Preact covers 3kB runtime.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which ConfigCat and Preact actually diverge.

Attributes where ConfigCat and Preact differ
AttributeConfigCatPreact
Pricing modelPer month by feature flag and environment countOpen source, no licence fee
PlatformsWeb, API, iOS, Android, Node.js, .NET, Java, Python, GoWeb
CategoryDeveloper ToolsWeb Development

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 ConfigCat

  • Feature flags and configuration
  • Percentage rollouts
  • Targeting rules and segments
  • Unlimited seats
  • Global CDN delivery
  • Audit log
  • Public API and webhooks
  • SDKs across languages

Only in Preact

  • 3kB runtime
  • preact/compat
  • Same modern API
  • Fast rendering

What people use each for

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

ConfigCat

  • A consumer or mobile app with millions of users where per-MAU flag pricing would cost more than the flags are worthnot Preact
  • A team that wants every engineer, product manager and support agent to have a login without paying per seatnot Preact
  • Decoupling deployment from release with percentage rollouts and a kill switch, without buying an experimentation platformnot Preact
  • A small team that needs ten flags permanently and can run indefinitely on the free tiernot Preact

Preact

  • Embedded widgets that load inside someone else’s page and must stay smallnot ConfigCat
  • Marketing and content sites where JavaScript payload affects Core Web Vitalsnot ConfigCat
  • Applications targeting low-bandwidth or low-powered devicesnot ConfigCat

Where each one falls short

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

ConfigCat

  • There is no experimentation or statistical analysis engine, so teams wanting real A/B tests with significance testing must buy and integrate a separate analytics or experimentation product.
  • Pricing by flag count punishes exactly the hygiene you want: the Pro tier caps at 100 flags, so teams that do not aggressively retire stale flags are pushed to the 325 dollar Smart tier for housekeeping reasons rather than growth.
  • The free tier allows only 2 environments, which does not cover the common development, staging and production split, so almost any real deployment starts on a paid plan.
  • It is a smaller vendor than the category incumbents, so enterprise procurement teams will find less depth in compliance attestations, contractual terms and reference architecture than LaunchDarkly offers.
  • Flag evaluation relies on SDK-side caching of a CDN-delivered config, which is fast but means propagation of a change is eventually consistent rather than instant, something to understand before relying on it as an emergency kill switch.

Preact

  • Compatibility through preact/compat is good but not total, and some React libraries break in ways that are hard to diagnose
  • Behavioural differences from React exist in edge cases, particularly around event handling
  • A much smaller community, so unusual problems have fewer existing answers than React

Pricing, plan by plan

ConfigCat

Free
  • Forever FreeFree
    • 10 feature flags
    • 2 environments and 2 products
    • 2 segments
  • Pro$110/month
    • 100 feature flags
    • 3 environments and 3 products
    • Unlimited seats and MAUs
  • Smart$325/month
    • Unlimited feature flags
    • Unlimited environments, products and segments
    • Unlimited seats and MAUs
  • Enterprise$900/month
    • Everything in Smart
    • Enterprise support and controls
    • Unlimited everything on flag counts

Preact

Free
  • PreactFree
    • Full library
    • Commercial use permitted
    • No usage limits

Which should you pick?

Choose ConfigCat if

  • You need feature flags and configuration.
  • You want to start without paying.
  • You work on Web, API, iOS, Android, Node.js, .NET, Java, Python, Go.
  • You also want percentage rollouts.
ConfigCat review

Choose Preact if

  • You need 3kb runtime.
  • You want to start without paying.
  • You also want preact/compat.
Preact review

Questions people ask

Is ConfigCat or Preact better?
Neither clearly leads. ConfigCat starts at Free and Preact at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, ConfigCat or Preact?
ConfigCat starts at Free and Preact at Free.
Does ConfigCat or Preact run on more platforms?
ConfigCat runs on Web, API, iOS, Android, Node.js, .NET, Java, Python, Go. Preact runs on Web.
Can I use ConfigCat for free?
Both have a free tier, so you can try either at no cost before committing.
What is ConfigCat best used for?
ConfigCat is most often used for a consumer or mobile app with millions of users where per-mau flag pricing would cost more than the flags are worth, a team that wants every engineer, product manager and support agent to have a login without paying per seat, decoupling deployment from release with percentage rollouts and a kill switch, without buying an experimentation platform, a small team that needs ten flags permanently and can run indefinitely on the free tier. Of those, a consumer or mobile app with millions of users where per-mau flag pricing would cost more than the flags are worth and a team that wants every engineer, product manager and support agent to have a login without paying per seat are not what Preact is typically brought in for.
What can ConfigCat do that Preact cannot?
ConfigCat covers Feature flags and configuration, Percentage rollouts, Targeting rules and segments, Unlimited seats. Preact covers 3kB runtime, preact/compat, Same modern API, Fast rendering.

Answered from the vendors’ own pages

ConfigCat: How is ConfigCat priced?

By feature flag, environment and product count. Seats, monthly active users and flag reads are unlimited on every plan.

Preact: Is Preact free?

Yes, open source under the MIT licence.

ConfigCat: Is the free tier usable?

For small projects yes, but at 10 flags and 2 environments it will not cover a dev, staging and production setup.

Preact: Can I use React libraries with Preact?

Most, through the preact/compat layer. Compatibility is good but not complete, so libraries relying on React internals can break.

ConfigCat: Can it run A/B tests?

It can split traffic, but there is no statistics engine. You need a separate analytics tool to decide a winner.

Preact: Why choose Preact over React?

Bundle size, almost always. If payload is not a binding constraint, React’s ecosystem is usually the better trade.

ConfigCat: How fast does a flag change take effect?

SDKs poll and cache, so changes propagate on the polling interval rather than instantly.

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