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Developer Tools · head to head

ConfigCat vs Envoy

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
Envoy logo

Envoy

Technology

A high-performance L7 proxy written in C++ that is configured by an API rather than a config file, and is usually deployed under a control plane.

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.; Envoy the configuration surface is very large and hand-written bootstrap YAML runs to hundreds of lines for routing that Nginx expresses in twenty, which is why nearly every production deployment sits under a control plane and inherits that control plane's constraints as well.
  • They diverge on capability: ConfigCat covers Feature flags and configuration, Envoy covers xDS dynamic configuration.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which ConfigCat and Envoy actually diverge.

Attributes where ConfigCat and Envoy differ
AttributeConfigCatEnvoy
Pricing modelPer month by feature flag and environment countopen-source
PlatformsWeb, API, iOS, Android, Node.js, .NET, Java, Python, GoWeb
CategoryDeveloper ToolsTechnology

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 Envoy

  • xDS dynamic configuration
  • Protocol breadth
  • Filter chain architecture
  • Observability by default
  • Outlier detection
  • Traffic shaping
  • mTLS termination and origination
  • Hot restart

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

Envoy

  • Acting as the data plane under a service mesh or Gateway API implementation, which is how the overwhelming majority of deployments use itnot ConfigCat
  • An edge or API gateway that needs per-route retry budgets, circuit breaking and outlier detection rather than round-robin proxyingnot ConfigCat
  • Migrating traffic between service versions or between a monolith and its replacement, using weighted splits and shadow trafficnot ConfigCat
  • Standardising observability across a polyglot estate, so that latency, error rates and tracing look the same regardless of the language a service is written innot 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.

Envoy

  • The configuration surface is very large and hand-written bootstrap YAML runs to hundreds of lines for routing that Nginx expresses in twenty, which is why nearly every production deployment sits under a control plane and inherits that control plane's constraints as well.
  • xDS is the real API and it is not stable in the comfortable sense; the v2 API set was removed outright, resource types continue to be deprecated, and your control plane and Envoy binaries have to be upgraded roughly in step or the proxies stop accepting configuration.
  • Extending it properly means writing a C++ filter and building and maintaining your own Envoy binary; the alternatives are Lua, which adds per-request overhead, and proxy-wasm, whose ABI has remained effectively experimental for years with a real performance cost.
  • At sidecar density the per-proxy memory and CPU footprint is a measurable share of cluster capacity, since thousands of workloads each carry a full proxy, and this is precisely the cost that has pushed mesh projects towards node-level or ambient architectures.
  • There is no single vendor selling support for Envoy itself; you get the community plus control-plane vendors such as Solo.io and Tetrate, so an Envoy-level production bug is your own engineers in a C++ codebase unless a support contract happens to cover it.
  • Diagnosing why a request got a particular response involves reading config dumps, the stats endpoint and the RESPONSE_FLAGS codes in access logs rather than a readable error, which is a specific skill you must hire or spend months growing.

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

Envoy

Free

No published plan breakdown. See the Envoy 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 Envoy if

  • You need xds dynamic configuration.
  • You want to start without paying.
  • You also want protocol breadth.
Envoy review

Questions people ask

Is ConfigCat or Envoy better?
Neither clearly leads. ConfigCat starts at Free and Envoy at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, ConfigCat or Envoy?
ConfigCat starts at Free and Envoy at Free.
Does ConfigCat or Envoy run on more platforms?
ConfigCat runs on Web, API, iOS, Android, Node.js, .NET, Java, Python, Go. Envoy 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 Envoy is typically brought in for.
What can ConfigCat do that Envoy cannot?
ConfigCat covers Feature flags and configuration, Percentage rollouts, Targeting rules and segments, Unlimited seats. Envoy covers xDS dynamic configuration, Protocol breadth, Filter chain architecture, Observability by default.

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.

Envoy: Should I run Envoy on its own, or under a control plane?

Almost always under one. Directly authoring xDS or static bootstrap configuration is viable for a handful of routes and becomes unmanageable beyond that. Envoy Gateway, Istio, Contour, Gloo and Consul all exist to generate that configuration for you.

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.

Envoy: How does it compare with Nginx or HAProxy?

Envoy is dynamically configured over an API and instrumented far more heavily; Nginx and HAProxy are faster to configure and lighter for straightforward reverse proxying. If you never need to change routing without a reload, Envoy is more machinery than the problem requires.

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.

Envoy: What does it cost?

Nothing to licence; it is Apache 2.0 and there is no paid edition. The cost is engineering time and, for most organisations, a commercial control plane or cloud service that packages it.

ConfigCat: How fast does a flag change take effect?

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

Envoy: Can I write extensions without C++?

You can write Lua filters or proxy-wasm modules in Rust, Go, C++ or AssemblyScript. Both carry per-request overhead compared with a native filter, and the Wasm path has been slower to stabilise than the project originally projected.

Envoy: Is it a CNCF project?

Yes, it is a graduated CNCF project licensed under Apache 2.0, which means the trademark and governance sit with the foundation rather than with Lyft or any vendor.

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