diff --git a/lib/entrypoint.test-d.ts b/lib/entrypoint.test-d.ts
index 393a7cdb8..a9a782522 100644
--- a/lib/entrypoint.test-d.ts
+++ b/lib/entrypoint.test-d.ts
@@ -94,6 +94,9 @@ export type Entrypoint = {
 
   // decide options
   OptimizelyDecideOption: typeof OptimizelyDecideOption;
+
+  // client engine
+  clientEngine: string;
 }
 
 
diff --git a/lib/index.browser.ts b/lib/index.browser.ts
index 8be972be3..b8c31659d 100644
--- a/lib/index.browser.ts
+++ b/lib/index.browser.ts
@@ -17,6 +17,7 @@ import { Config, Client } from './shared_types';
 import sendBeaconEventDispatcher from './event_processor/event_dispatcher/send_beacon_dispatcher.browser';
 import { getOptimizelyInstance } from './client_factory';
 import { EventDispatcher } from './event_processor/event_dispatcher/event_dispatcher';
+import { JAVASCRIPT_CLIENT_ENGINE } from './utils/enums';
 
 /**
  * Creates an instance of the Optimizely class
@@ -55,3 +56,5 @@ export { createVuidManager } from './vuid/vuid_manager_factory.browser';
 export * from './common_exports';
 
 export * from './export_types';
+
+export const clientEngine: string = JAVASCRIPT_CLIENT_ENGINE;
diff --git a/lib/index.node.ts b/lib/index.node.ts
index e39501e83..cb1802af8 100644
--- a/lib/index.node.ts
+++ b/lib/index.node.ts
@@ -48,3 +48,5 @@ export { createVuidManager } from './vuid/vuid_manager_factory.node';
 export * from './common_exports';
 
 export * from './export_types';
+
+export const clientEngine: string = NODE_CLIENT_ENGINE;
diff --git a/lib/index.react_native.ts b/lib/index.react_native.ts
index 4cf20fccd..48a8ee35c 100644
--- a/lib/index.react_native.ts
+++ b/lib/index.react_native.ts
@@ -51,3 +51,5 @@ export { createVuidManager } from './vuid/vuid_manager_factory.react_native';
 export * from './common_exports';
 
 export * from './export_types';
+
+export const clientEngine: string = REACT_NATIVE_JS_CLIENT_ENGINE;