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Developer Tools · head to head

ConfigCat vs esbuild

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
esbuild logo

esbuild

Web Development

Extremely fast JavaScript bundler written in Go

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.; esbuild deliberately does not type-check TypeScript, only strips types, so tsc still runs separately
  • They diverge on capability: ConfigCat covers Feature flags and configuration, esbuild covers Very fast builds.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which ConfigCat and esbuild actually diverge.

Attributes where ConfigCat and esbuild differ
AttributeConfigCatesbuild
Pricing modelPer month by feature flag and environment countOpen source, no licence fee
PlatformsWeb, API, iOS, Android, Node.js, .NET, Java, Python, GoLinux, macOS, Windows
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 esbuild

  • Very fast builds
  • TypeScript support
  • Tree shaking and minification
  • Simple API

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 esbuild
  • A team that wants every engineer, product manager and support agent to have a login without paying per seatnot esbuild
  • Decoupling deployment from release with percentage rollouts and a kill switch, without buying an experimentation platformnot esbuild
  • A small team that needs ten flags permanently and can run indefinitely on the free tiernot esbuild

esbuild

  • Build pipelines where bundle time is the bottlenecknot ConfigCat
  • Libraries and tools needing a fast, embeddable bundlernot ConfigCat
  • Replacing slower bundlers where the plugin ecosystem is not needednot 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.

esbuild

  • Deliberately does not type-check TypeScript, only strips types, so tsc still runs separately
  • Plugin API is far narrower than webpack or Rollup, and complex builds hit its limits
  • Code splitting support has historically lagged the more established bundlers
  • Frequently used indirectly through Vite, so direct use is a narrower need than the download numbers suggest

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

esbuild

Free
  • esbuildFree
    • Full functionality
    • Commercial use permitted
    • Community support

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 esbuild if

  • You need very fast builds.
  • You want to start without paying.
  • You work on Linux, macOS, Windows.
  • You also want typescript support.
esbuild review

Questions people ask

Is ConfigCat or esbuild better?
Neither clearly leads. ConfigCat starts at Free and esbuild at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, ConfigCat or esbuild?
ConfigCat starts at Free and esbuild at Free.
Does ConfigCat or esbuild run on more platforms?
ConfigCat runs on Web, API, iOS, Android, Node.js, .NET, Java, Python, Go. esbuild runs on Linux, macOS, Windows.
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 esbuild is typically brought in for.
What can ConfigCat do that esbuild cannot?
ConfigCat covers Feature flags and configuration, Percentage rollouts, Targeting rules and segments, Unlimited seats. esbuild covers Very fast builds, TypeScript support, Tree shaking and minification, Simple API.

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.

esbuild: Is esbuild 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.

esbuild: Does esbuild type-check TypeScript?

No. It strips types for speed and does not check them. Run tsc separately if you need type checking.

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.

esbuild: Do I need esbuild if I use Vite?

You already have it. Vite uses esbuild internally for dependency pre-bundling and transforms.

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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