diff --git a/npm/ng-packs/packages/core/src/lib/services/localization.service.ts b/npm/ng-packs/packages/core/src/lib/services/localization.service.ts
index a26f1af06f..e449c4afb9 100644
--- a/npm/ng-packs/packages/core/src/lib/services/localization.service.ts
+++ b/npm/ng-packs/packages/core/src/lib/services/localization.service.ts
@@ -23,13 +23,12 @@ export class LocalizationService {
     if (otherInstance) throw new Error('LocaleService should have only one instance.');
   }
 
-  private setRouteReuse(reuse: ShouldReuseRoute) {
+  setRouteReuse(reuse: ShouldReuseRoute) {
     this.router.routeReuseStrategy.shouldReuseRoute = reuse;
   }
 
   registerLocale(locale: string) {
     const { shouldReuseRoute } = this.router.routeReuseStrategy;
-
     this.setRouteReuse(() => false);
     this.router.navigated = false;
 
@@ -41,11 +40,11 @@ export class LocalizationService {
     });
   }
 
-  get(keys: string, ...interpolateParams: string[]): Observable<string> {
-    return this.store.select(state => state.ConfigState.getCopy(keys, ...interpolateParams));
+  get(key: string, ...interpolateParams: string[]): Observable<string> {
+    return this.store.select(state => state.ConfigState.getLocalization(key, ...interpolateParams));
   }
 
-  instant(keys: string, ...interpolateParams: string[]): string {
-    return this.store.selectSnapshot(state => state.ConfigState.getCopy(keys, ...interpolateParams));
+  instant(key: string, ...interpolateParams: string[]): string {
+    return this.store.selectSnapshot(state => state.ConfigState.getLocalization(key, ...interpolateParams));
   }
 }
diff --git a/npm/ng-packs/packages/core/src/lib/states/config.state.ts b/npm/ng-packs/packages/core/src/lib/states/config.state.ts
index 29799a502b..1dcc5d8512 100644
--- a/npm/ng-packs/packages/core/src/lib/states/config.state.ts
+++ b/npm/ng-packs/packages/core/src/lib/states/config.state.ts
@@ -113,6 +113,11 @@ export class ConfigState {
     return selector;
   }
 
+  /**
+   *
+   * @param deprecated, Use getLocalization instead. To be delete in v1
+   *
+   */
   static getCopy(key: string, ...interpolateParams: string[]) {
     if (!key) key = '';
 
@@ -161,6 +166,54 @@ export class ConfigState {
     return selector;
   }
 
+  static getLocalization(key: string, ...interpolateParams: string[]) {
+    if (!key) key = '';
+
+    const keys = key.split('::') as string[];
+    const selector = createSelector(
+      [ConfigState],
+      (state: Config.State) => {
+        if (!state.localization) return key;
+
+        const { defaultResourceName } = state.environment.localization;
+        if (keys[0] === '') {
+          if (!defaultResourceName) {
+            throw new Error(
+              `Please check your environment. May you forget set defaultResourceName?
+              Here is the example:
+               { production: false,
+                 localization: {
+                   defaultResourceName: 'MyProjectName'
+                  }
+               }`,
+            );
+          }
+
+          keys[0] = snq(() => defaultResourceName);
+        }
+
+        let localization = (keys as any).reduce((acc, val) => {
+          if (acc) {
+            return acc[val];
+          }
+
+          return undefined;
+        }, state.localization.values);
+
+        interpolateParams = interpolateParams.filter(params => params != null);
+        if (localization && interpolateParams && interpolateParams.length) {
+          interpolateParams.forEach(param => {
+            localization = localization.replace(/[\'\"]?\{[\d]+\}[\'\"]?/, param);
+          });
+        }
+
+        return localization || key;
+      },
+    );
+
+    return selector;
+  }
+
   constructor(private appConfigurationService: ApplicationConfigurationService, private store: Store) {}
 
   @Action(GetAppConfiguration)
diff --git a/npm/ng-packs/packages/core/src/lib/tests/localization.service.spec.ts b/npm/ng-packs/packages/core/src/lib/tests/localization.service.spec.ts
new file mode 100644
index 0000000000..c279fb6da2
--- /dev/null
+++ b/npm/ng-packs/packages/core/src/lib/tests/localization.service.spec.ts
@@ -0,0 +1,81 @@
+import { Router } from '@angular/router';
+import { createServiceFactory, SpectatorService, SpyObject } from '@ngneat/spectator';
+import { Store } from '@ngxs/store';
+import { Observable, of } from 'rxjs';
+import { LocalizationService } from '../services/localization.service';
+
+describe('LocalizationService', () => {
+  let spectator: SpectatorService<LocalizationService>;
+  let store: SpyObject<Store>;
+  let service: LocalizationService;
+
+  const createService = createServiceFactory({
+    service: LocalizationService,
+    entryComponents: [],
+    mocks: [Store, Router],
+  });
+
+  beforeEach(() => {
+    spectator = createService();
+    store = spectator.get(Store);
+    service = spectator.service;
+  });
+
+  describe('#currentLang', () => {
+    it('should be tr', () => {
+      store.selectSnapshot.andCallFake((selector: (state: any, ...states: any[]) => string) => {
+        return selector({ SessionState: { getLanguage: 'tr' } });
+      });
+
+      expect(service.currentLang).toBe('tr');
+    });
+  });
+
+  describe('#get', () => {
+    it('should be return an observable localization', async () => {
+      store.select.andCallFake((selector: (state: any, ...states: any[]) => Observable<string>) => {
+        return selector({ ConfigState: { getLocalization: (keys, ...interpolateParams) => of(keys) } });
+      });
+
+      const localization = await service.get('AbpTest').toPromise();
+
+      expect(localization).toBe('AbpTest');
+    });
+  });
+
+  describe('#instant', () => {
+    it('should be return a localization', () => {
+      store.selectSnapshot.andCallFake((selector: (state: any, ...states: any[]) => Observable<string>) => {
+        return selector({ ConfigState: { getLocalization: (keys, ...interpolateParams) => keys } });
+      });
+
+      expect(service.instant('AbpTest')).toBe('AbpTest');
+    });
+  });
+
+  describe('#registerLocale', () => {
+    it('should return registerLocale and then call setRouteReuse', () => {
+      const router = spectator.get(Router);
+
+      const shouldReuseRoute = () => true;
+      router.routeReuseStrategy = { shouldReuseRoute } as any;
+
+      router.navigateByUrl.andCallFake(url => {
+        return new Promise(resolve => resolve({ catch: () => null }));
+      });
+
+      service.registerLocale('tr');
+
+      expect(router.navigated).toBe(false);
+      expect(router.routeReuseStrategy.shouldReuseRoute).not.toEqual(shouldReuseRoute);
+    });
+
+    it('should throw an error message when service have an otherInstance', async () => {
+      try {
+        const instance = new LocalizationService(null, null, null, {} as any);
+      } catch (error) {
+        expect((error as Error).message).toBe('LocaleService should have only one instance.');
+      }
+    });
+  });
+});
diff --git a/npm/ng-packs/packages/theme-shared/src/lib/tests/state-overwrite.ts b/npm/ng-packs/packages/core/src/lib/tests/state-overwrite.ts
similarity index 100%
rename from npm/ng-packs/packages/theme-shared/src/lib/tests/state-overwrite.ts
rename to npm/ng-packs/packages/core/src/lib/tests/state-overwrite.ts