ConfigCat is a feature flag and configuration management service that lets you separate releases from deployments. You can turn your features ON/OFF using ConfigCat Management Console even after they are deployed. ConfigCat lets you target specific groups of users based on region, email or any other custom user attribute.
For SSR (Server-Side Rendering) Universal applications use configcat-node SDK.
1. Install and import package:
via NPM package:
npm i configcat-js
Connect your application tab to get your API Key:2. Go to
3. Create a ConfigCat client instance:
var configCatClient = configcat;
We strongly recommend using the ConfigCat Client as a Singleton object in your application.
4. Get your setting value:
The Promise (async/await) way:
or the Callback way:
Getting user specific setting values with Targeting
Using this feature, you will be able to get different setting values for different users in your application by passing a
User Object to
Read more about Targeting here.
const userObject = identifier : "#USER-IDENTIFIER#" ;configCatClient;
The ConfigCat SDK supports 3 different polling mechanisms to acquire the setting values from ConfigCat. After latest setting values are downloaded, they are stored in the internal cache then all requests are served from there. Read more about Polling Modes and how to use them at ConfigCat Docs.
If you need help how to use this SDK feel free to to contact the ConfigCat Staff on https://configcat.com. We're happy to help.
Contributions are welcome.
XMLHttpRequest module not defined/found:
configcat-js SDK needs to download the feature flag and setting values from ConfigCat's servers via a HTTP GET request. The SDK uses
XMLHttpRequest a built in object in all browsers. This way the package size is smaller instead of using a 3rd party library. The error above can appear in cases when the
configcat-js SDK is used within a SSR (Server-Side Rendering) Universal application. In these cases we recommend using configcat-node SDK.