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ConfigCat vs Rust

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
Rust logo

Rust

Developer Tools

A language empowering everyone to build reliable and efficient software

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.; Rust compile times significantly longer than languages like Go or C
  • They diverge on capability: ConfigCat covers Feature flags and configuration, Rust covers Memory safety.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which ConfigCat and Rust actually diverge.

Attributes where ConfigCat and Rust differ
AttributeConfigCatRust
Pricing modelPer month by feature flag and environment countopen-source
PlatformsWeb, API, iOS, Android, Node.js, .NET, Java, Python, GoWindows, Linux, macOS
FoundedUnknown2010

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 Rust

  • Memory safety
  • Zero-cost abstractions
  • Ownership system
  • Pattern matching
  • Type inference
  • Cargo package manager
  • Cross compilation
  • Fearless concurrency

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

Rust

  • Systems programming and operating system developmentnot ConfigCat
  • Performance-critical applicationsnot ConfigCat
  • Embedded systems and firmwarenot ConfigCat
  • Network services and concurrent applicationsnot 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.

Rust

  • Compile times significantly longer than languages like Go or C
  • Smaller ecosystem of libraries and frameworks compared to Python or JavaScript
  • Community still smaller than mainstream languages, reducing available third-party resources

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

Rust

Free

No published plan breakdown. See the Rust 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 Rust if

  • You need memory safety.
  • You want to start without paying.
  • You work on Windows, Linux, macOS.
  • You also want zero-cost abstractions.
Rust review

Questions people ask

Is ConfigCat or Rust better?
Neither clearly leads. ConfigCat starts at Free and Rust at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, ConfigCat or Rust?
ConfigCat starts at Free and Rust at Free.
Does ConfigCat or Rust run on more platforms?
ConfigCat runs on Web, API, iOS, Android, Node.js, .NET, Java, Python, Go. Rust runs on Windows, Linux, macOS.
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 Rust is typically brought in for.
What can ConfigCat do that Rust cannot?
ConfigCat covers Feature flags and configuration, Percentage rollouts, Targeting rules and segments, Unlimited seats. Rust covers Memory safety, Zero-cost abstractions, Ownership system, Pattern matching.

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.

Rust: Is Rust free?

Yes, Rust is free and open-source. The Rust Foundation provides institutional support for this community-driven project, and there are no costs associated with using the programming language.

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.

Rust: What license does Rust use?

Rust is open-source and operated under an open-source license. Full license details are available in the policies section of the Rust website.

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.

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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