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Developer Tools · head to head

ConfigCat vs ESLint

ConfigCat logo

ConfigCat

Developer Tools

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

From
Free
Rated
-
Full reviewWebsite
ESLint logo

ESLint

Developer Tools

Find and fix problems in JavaScript code

From
Free
Rated
-
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.; ESLint slow performance on large codebases compared to newer tools like Oxlint and Biome
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which ConfigCat and ESLint actually diverge.

Attributes where ConfigCat and ESLint differ
AttributeConfigCatESLint
Pricing modelPer month by feature flag and environment countUnknown
PlatformsWeb, API, iOS, Android, Node.js, .NET, Java, Python, GoBrowser-based JavaScript, Node.js, Any JavaScript environment
FoundedUnknown2019

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

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 ESLint

Nothing recorded that ConfigCat does not also cover.

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

ESLint

  • Statically analysing JavaScript and JSX to find problems before runtimenot ConfigCat
  • Automatically fixing issues with syntax-aware rewritesnot ConfigCat
  • Enforcing a consistent code style across a teamnot ConfigCat
  • Running as a CI step to block non-conforming codenot ConfigCat
  • Writing custom rules for project-specific conventionsnot 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.

ESLint

  • Slow performance on large codebases compared to newer tools like Oxlint and Biome
  • Complexity in configuration from scratch, particularly for TypeScript support
  • Limited built-in TypeScript support, requiring separate parsers and coordination with new TypeScript features

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

ESLint

Free

No published plan breakdown. See the ESLint review.

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 ESLint if

  • You want to start without paying.
  • You work on Browser-based JavaScript, Node.js, Any JavaScript environment.
ESLint review

Questions people ask

Is ConfigCat or ESLint better?
Neither clearly leads. ConfigCat starts at Free and ESLint at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, ConfigCat or ESLint?
ConfigCat starts at Free and ESLint at Free.
Does ConfigCat or ESLint run on more platforms?
ConfigCat runs on Web, API, iOS, Android, Node.js, .NET, Java, Python, Go. ESLint runs on Browser-based JavaScript, Node.js, Any JavaScript environment.
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 ESLint is typically brought in for.
What can ConfigCat do that ESLint cannot?
ConfigCat covers Feature flags and configuration, Percentage rollouts, Targeting rules and segments, Unlimited seats.

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.

ESLint: Does ESLint automatically fix code issues?

Many problems ESLint finds can be automatically fixed via the --fix flag. ESLint fixes are syntax-aware so you won't experience errors introduced by traditional find-and-replace algorithms.

Source
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.

ESLint: How much does ESLint cost?

ESLint is completely free and open-source software maintained by the OpenJS Foundation. The project accepts voluntary donations from sponsors.

Source
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.

ESLint: Can I write custom ESLint rules?

Yes. You can develop custom rules that work alongside built-in functionality through ESLint's plugin system, allowing complete customization for your project needs.

Source
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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