Flagsmith SDK API

The SDK API is designed to be used by Flagsmith SDKs to evaluate feature flags and retrieve environment data.

Authentication

The SDK API is designed to be publicly accessible. Calls need to have an environment key supplied with each request. This is provided as an HTTP header, with the name X-Environment-Key and the value of the Environment Key that you can find within the Flagsmith administrative area. See Flags API Authentication for more details.

Core API

Please note that the SDK API is specifically to be used with our SDKs. If you want to drive aspects of Flagsmith programmatically, you need to use our private Core API.

You can find the full spec to our Core API here.