How does ConfigCat work?


  1. You set your Feature Flags on the ConfigCat Dashboard.
  2. Your Feature Flags get distributed across the ConfigCat CDN.
  3. Your application downloads and evaluates your Feature Flags.

Feature flag evaluation is on the client side

  1. The ConfigCat SDK frequently downloads the feature flag values from the CDN.
  2. The latest feature flag values are cached locally.
  3. Your application code requests a feature flag value for a user.
  4. The SDK evaluates locally and serves without uploading any sensitive user information.
Architecture diagram of ConfigCat


A graphical user interface even for non-technical people to manage Feature Flags and teams easily. Dashboard

CDN Nodes

Serves our customers' config.json files. They are designed to scale quickly and to handle a massive number of requests.

Data Center Locations:

  • EU: Frankfurt, Amsterdam
  • America: New York City, Newark, Fremont, San Francisco
  • Asia & Oceania: Singapore, Sydney

GDPR consideration: The Data Governance feature lets you use our EU Only CDN nodes.

ConfigCat Data Center Locations

ConfigCat SDKs

The SDK is responsible for downloading and caching the config.json files. It also provides an interface to access Feature Flag values from any Desktop, Mobile, Frontend, or Backend application code. All the SDKs are open source on GitHub.

Requests & config.json downloads

A config.json download is counted every time your application downloads a configuration file from the ConfigCat CDN. The frequency of these downloads is totally under your control. Between downloads, you can access your feature flags as many times as you like, it still counts as one config.json download.
Learn more on how to forecast the number of downloads.

You can monitor the amount of your config.json downloads in real-time on the ConfigCat Dashboard.

ConfigCat real time config.json download statistics.

Public Management API

Publicly available API to provide management access to Feature Flags programmatically.