diff --git a/packages/core/src/Properties.ts b/packages/core/src/Properties.ts
index e058f96000..d8bca379da 100644
--- a/packages/core/src/Properties.ts
+++ b/packages/core/src/Properties.ts
@@ -1,5 +1,5 @@
 import { TolgeeConfig } from './TolgeeConfig';
-import { Scope } from './types';
+import { Mode, Scope } from './types';
 
 const PREFERRED_LANGUAGES_LOCAL_STORAGE_KEY = '__tolgee_preferredLanguages';
 const CURRENT_LANGUAGE_LOCAL_STORAGE_KEY = '__tolgee_currentLanguage';
@@ -9,6 +9,7 @@ export class Properties {
   scopes?: Scope[];
   projectId?: number;
   permittedLanguageIds?: number[];
+  mode?: Mode;
   _currentLanguage?: string;
 
   get currentLanguage(): string {
diff --git a/packages/core/src/Tolgee.test.ts b/packages/core/src/Tolgee.test.ts
index b162253cc5..0c445eef08 100644
--- a/packages/core/src/Tolgee.test.ts
+++ b/packages/core/src/Tolgee.test.ts
@@ -48,7 +48,7 @@ describe('Tolgee', () => {
   });
 
   test('will load api key details', async () => {
-    propertiesMock.mock.instances[0].config.mode = 'development';
+    propertiesMock.mock.instances[0].mode = 'development';
     await tolgee.run();
     expect(
       coreServiceMock.mock.instances[0].loadApiKeyDetails
@@ -59,7 +59,7 @@ describe('Tolgee', () => {
   });
 
   test('will not set properties.scopes on run in production mode', async () => {
-    propertiesMock.mock.instances[0].config.mode = 'production';
+    propertiesMock.mock.instances[0].mode = 'production';
     await tolgee.run();
     expect(coreServiceMock.mock.instances[0].getApiKeyDetails).toBeCalledTimes(
       0
@@ -149,7 +149,7 @@ describe('Tolgee', () => {
 
     describe('async translate', () => {
       test('will return wrapped string from text service in development mode', async () => {
-        propertiesMock.mock.instances[0].config.mode = 'development';
+        propertiesMock.mock.instances[0].mode = 'development';
         const translated = await tolgee.translate(dummyKey, dummyParams);
 
         expect(mockedWrap).toBeCalledWith(
@@ -162,7 +162,7 @@ describe('Tolgee', () => {
       });
 
       test('will return translated string from text service in production mode', async () => {
-        propertiesMock.mock.instances[0].config.mode = 'production';
+        propertiesMock.mock.instances[0].mode = 'production';
         const translated = await tolgee.translate(dummyKey, dummyParams);
 
         expect(translated).toEqual(translatedDummyText);
@@ -177,7 +177,7 @@ describe('Tolgee', () => {
       });
 
       test('will not wrap when development is on, but noWrap is true', async () => {
-        propertiesMock.mock.instances[0].config.mode = 'development';
+        propertiesMock.mock.instances[0].mode = 'development';
         const translated = await tolgee.translate(dummyKey, dummyParams, true);
 
         expect(mockedWrap).not.toBeCalled();
@@ -185,13 +185,13 @@ describe('Tolgee', () => {
       });
 
       test('will wait for translations load before wrapping', async () => {
-        propertiesMock.mock.instances[0].config.mode = 'development';
+        propertiesMock.mock.instances[0].mode = 'development';
         await tolgee.translate(dummyKey, dummyParams);
         expect(mockedLoadTranslations).toBeCalled();
       });
 
       test('passes default value to wrap fn', async () => {
-        propertiesMock.mock.instances[0].config.mode = 'development';
+        propertiesMock.mock.instances[0].mode = 'development';
         await tolgee.translate(dummyKey, dummyParams, false, 'Default');
         expect(mockedWrap).toBeCalledWith(
           'dummyText',
@@ -202,7 +202,7 @@ describe('Tolgee', () => {
       });
 
       test('passes default value to translate fn', async () => {
-        propertiesMock.mock.instances[0].config.mode = 'development';
+        propertiesMock.mock.instances[0].mode = 'development';
         await tolgee.translate(dummyKey, dummyParams, true, 'Default');
         expect(mockedTranslate).toBeCalledWith(
           'dummyText',
@@ -214,7 +214,7 @@ describe('Tolgee', () => {
       });
 
       test('props object works correctly', async () => {
-        propertiesMock.mock.instances[0].config.mode = 'development';
+        propertiesMock.mock.instances[0].mode = 'development';
         await tolgee.translate({
           key: dummyKey,
           params: dummyParams,
@@ -231,7 +231,7 @@ describe('Tolgee', () => {
       });
 
       test('passes orEmpty correctly', async () => {
-        propertiesMock.mock.instances[0].config.mode = 'development';
+        propertiesMock.mock.instances[0].mode = 'development';
         await tolgee.translate({
           key: dummyKey,
           params: dummyParams,
@@ -250,7 +250,7 @@ describe('Tolgee', () => {
 
     describe('sync instant', () => {
       test('will return wrapped string from text service in development mode', async () => {
-        propertiesMock.mock.instances[0].config.mode = 'development';
+        propertiesMock.mock.instances[0].mode = 'development';
         const dummyParams = {};
         const translated = tolgee.instant(dummyKey, dummyParams);
 
@@ -264,7 +264,7 @@ describe('Tolgee', () => {
       });
 
       test('will return translated string from text service in production mode', async () => {
-        propertiesMock.mock.instances[0].config.mode = 'production';
+        propertiesMock.mock.instances[0].mode = 'production';
         const translated = tolgee.instant(dummyKey, dummyParams);
 
         expect(translated).toEqual(translatedDummyText);
@@ -290,7 +290,7 @@ describe('Tolgee', () => {
       });
 
       test('will not wrap when development is on, but noWrap is true', async () => {
-        propertiesMock.mock.instances[0].config.mode = 'development';
+        propertiesMock.mock.instances[0].mode = 'development';
         const translated = tolgee.instant(dummyKey, dummyParams, true);
 
         expect(mockedWrap).not.toBeCalled();
@@ -309,7 +309,7 @@ describe('Tolgee', () => {
       });
 
       test('passes default value to wrap fn', async () => {
-        propertiesMock.mock.instances[0].config.mode = 'development';
+        propertiesMock.mock.instances[0].mode = 'development';
         const dummyParams = {};
         tolgee.instant(dummyKey, dummyParams, false, false, 'Default');
 
@@ -322,7 +322,7 @@ describe('Tolgee', () => {
       });
 
       test('props object works correctly', async () => {
-        propertiesMock.mock.instances[0].config.mode = 'development';
+        propertiesMock.mock.instances[0].mode = 'development';
         await tolgee.instant({
           key: dummyKey,
           params: dummyParams,
@@ -341,7 +341,7 @@ describe('Tolgee', () => {
     });
 
     test('passes default value to instant fn', async () => {
-      propertiesMock.mock.instances[0].config.mode = 'development';
+      propertiesMock.mock.instances[0].mode = 'development';
       const dummyParams = {};
       tolgee.instant(dummyKey, dummyParams, true, false, 'Default');
 
@@ -372,7 +372,7 @@ describe('Tolgee', () => {
   });
 
   test('will return proper initialLoading', () => {
-    tolgee.properties.config.mode = 'production';
+    tolgee.properties.mode = 'production';
     tolgee.properties.config.preloadFallback = true;
     tolgee.properties.currentLanguage = 'cs';
     tolgee.properties.config.staticData = {
@@ -385,7 +385,7 @@ describe('Tolgee', () => {
     tolgee.properties.config.preloadFallback = true;
     tolgee.properties.config.staticData.en = {};
     expect(tolgee.initialLoading).toEqual(false);
-    tolgee.properties.config.mode = 'development';
+    tolgee.properties.mode = 'development';
     expect(tolgee.initialLoading).toEqual(false);
   });
 
diff --git a/packages/core/src/Tolgee.ts b/packages/core/src/Tolgee.ts
index 28af038dc4..8d80971663 100644
--- a/packages/core/src/Tolgee.ts
+++ b/packages/core/src/Tolgee.ts
@@ -124,20 +124,24 @@ export class Tolgee {
 
   init(config: TolgeeConfig) {
     this.dependencyService.init(config);
+    const { apiKey, apiUrl } = this.dependencyService.properties.config;
+    this.dependencyService.properties.mode =
+      apiKey && apiUrl ? 'development' : 'production';
+
     return this;
   }
 
   public async run(): Promise<void> {
     this.dependencyService.run();
-    if (this.properties.config.mode === 'development') {
+    if (this.properties.mode === 'development') {
       try {
         await this.coreService.loadApiKeyDetails();
       } catch (e) {
         // eslint-disable-next-line no-console
-        console.error("Couldn't connect to tolgee");
+        console.error("Couldn't connect to Tolgee");
         // eslint-disable-next-line no-console
         console.error(e);
-        this.properties.config.mode = 'production';
+        this.properties.mode = 'production';
       }
     }
 
@@ -206,7 +210,7 @@ export class Tolgee {
       defaultValue
     );
 
-    if (this.properties.config.mode === 'development' && !noWrap) {
+    if (this.properties.mode === 'development' && !noWrap) {
       await this.coreService.loadApiKeyDetails();
       return this.dependencyService.wrapper.wrap(
         key,
@@ -238,7 +242,7 @@ export class Tolgee {
     defaultValue?: string | undefined,
     translation?: TranslationTags<any>
   ): TranslationTags<any> {
-    if (this.properties.config.mode === 'development') {
+    if (this.properties.mode === 'development') {
       return this.dependencyService.wrapper.wrap(
         key,
         params,
@@ -295,7 +299,7 @@ export class Tolgee {
       defaultValue
     );
 
-    if (this.properties.config.mode === 'development' && !noWrap) {
+    if (this.properties.mode === 'development' && !noWrap) {
       return this.dependencyService.wrapper.wrap(
         key,
         params,
diff --git a/packages/core/src/TolgeeConfig.ts b/packages/core/src/TolgeeConfig.ts
index ca5560c8c7..66a2b78006 100644
--- a/packages/core/src/TolgeeConfig.ts
+++ b/packages/core/src/TolgeeConfig.ts
@@ -1,6 +1,7 @@
-import { Mode, TreeTranslationsData } from './types';
+import { TreeTranslationsData } from './types';
 import { NodeHelper } from './helpers/NodeHelper';
 import { ModifierKey } from './Constants/ModifierKey';
+import { Mode } from 'fs';
 
 const API_KEY_LOCAL_STORAGE = '__tolgee_apiKey';
 const API_URL_LOCAL_STORAGE = '__tolgee_apiUrl';
@@ -24,6 +25,10 @@ type UiType =
   | Promise<UiLibInterface>;
 
 export class TolgeeConfig {
+  /**
+   * @deprecated This option won't have any effect,
+   * because mode is now automatically detected when apiKey + apiUrl are set
+   */
   mode?: Mode;
   apiUrl?: string;
   apiKey?: string;
@@ -117,10 +122,9 @@ export class TolgeeConfig {
     if (this._targetElement === undefined) {
       this._targetElement = DEFAULT_TARGET_ELEMENT_SUPPLIER();
     }
-    this.mode = this.mode || (this.apiKey ? 'development' : 'production');
     this.fallbackLanguage = this.fallbackLanguage || this.defaultLanguage;
     if (this.watch === undefined) {
-      this.watch = this.mode === 'development';
+      this.watch = Boolean(this.apiKey && this.apiUrl);
     }
     if (this.availableLanguages === undefined && this.staticData) {
       this.availableLanguages = Object.keys(this.staticData);
diff --git a/packages/core/src/services/CoreService.test.ts b/packages/core/src/services/CoreService.test.ts
index 1885842a73..34c918763b 100644
--- a/packages/core/src/services/CoreService.test.ts
+++ b/packages/core/src/services/CoreService.test.ts
@@ -77,7 +77,7 @@ describe('CoreService', () => {
         throw new Error();
       });
       await coreService.getApiKeyDetails();
-      expect(getMockedInstance(Properties).config.mode).toEqual('production');
+      expect(getMockedInstance(Properties).mode).toEqual('production');
       // eslint-disable-next-line no-console
       expect(console.error).toBeCalledTimes(2);
     });
@@ -102,7 +102,7 @@ describe('CoreService', () => {
 
     test('will set properties.scopes on run in development mode', async () => {
       const propertiesMock = getMockedInstance(Properties);
-      propertiesMock.config.mode = 'development';
+      propertiesMock.mode = 'development';
       await coreService.loadApiKeyDetails();
       expect(propertiesMock.scopes).toContain('translations.edit' as Scope);
       expect(propertiesMock.scopes).not.toContain('translations.view' as Scope);
@@ -110,7 +110,7 @@ describe('CoreService', () => {
 
     test('will set properties.projectId on run in development mode', async () => {
       const propertiesMock = getMockedInstance(Properties);
-      propertiesMock.config.mode = 'development';
+      propertiesMock.mode = 'development';
       await coreService.loadApiKeyDetails();
       expect(propertiesMock.projectId).toEqual(0);
     });
diff --git a/packages/core/src/services/CoreService.ts b/packages/core/src/services/CoreService.ts
index 6f5046ff1f..7821738fb4 100644
--- a/packages/core/src/services/CoreService.ts
+++ b/packages/core/src/services/CoreService.ts
@@ -49,7 +49,7 @@ export class CoreService {
       console.error(
         'Error getting scopes. Trying to switch to production mode!'
       );
-      this.properties.config.mode = 'production';
+      this.properties.mode = 'production';
     }
   }
 
diff --git a/packages/core/src/services/ElementRegistrar.test.ts b/packages/core/src/services/ElementRegistrar.test.ts
index b47ebd1efc..11fb8fa7f3 100644
--- a/packages/core/src/services/ElementRegistrar.test.ts
+++ b/packages/core/src/services/ElementRegistrar.test.ts
@@ -35,7 +35,7 @@ describe('ElementRegistrar', () => {
     const element = createElement(1, 1);
 
     beforeEach(async () => {
-      getMockedInstance(Properties).config.mode = 'development';
+      getMockedInstance(Properties).mode = 'development';
       document.body.append(element);
       await elementRegistrar.register(element);
     });
@@ -57,7 +57,7 @@ describe('ElementRegistrar', () => {
 
   test('throws error on register element without any node', async () => {
     const element = createElement(0, 0);
-    getMockedInstance(Properties).config.mode = 'development';
+    getMockedInstance(Properties).mode = 'development';
     document.body.append(element);
     elementRegistrar.register(element);
     expect((elementRegistrar as any).registeredElements).toBeInstanceOf(Set);
diff --git a/packages/core/src/services/ElementRegistrar.ts b/packages/core/src/services/ElementRegistrar.ts
index 5e00fc6b73..2ea5359e3f 100644
--- a/packages/core/src/services/ElementRegistrar.ts
+++ b/packages/core/src/services/ElementRegistrar.ts
@@ -24,7 +24,7 @@ export class ElementRegistrar {
       return;
     }
     if (
-      this.properties.config.mode === 'development' &&
+      this.properties.mode === 'development' &&
       !this.registeredElements.has(element)
     ) {
       this.translationHighlighter.listen(element);
diff --git a/packages/core/src/services/TranslationService.test.ts b/packages/core/src/services/TranslationService.test.ts
index 39cdeab478..b266b05241 100644
--- a/packages/core/src/services/TranslationService.test.ts
+++ b/packages/core/src/services/TranslationService.test.ts
@@ -79,7 +79,7 @@ describe('TranslationService', () => {
     });
 
     test('will load translations in development mode', async () => {
-      getMockedInstance(Properties).config.mode = 'development';
+      getMockedInstance(Properties).mode = 'development';
       await translationService.loadTranslations('en');
       expect(translationService.getFromCacheOrFallback('key', 'en')).toEqual(
         'translated'
@@ -184,7 +184,7 @@ describe('TranslationService', () => {
     });
 
     test("won't throw exception when there is null in translation data", async () => {
-      getMockedInstance(Properties).config.mode = 'development';
+      getMockedInstance(Properties).mode = 'development';
       getMockedInstance(ApiHttpService).fetchJson = jest.fn(async () => ({
         en: {
           hello: null,
diff --git a/packages/core/src/services/TranslationService.ts b/packages/core/src/services/TranslationService.ts
index 7f66fd67ba..d6badd9919 100644
--- a/packages/core/src/services/TranslationService.ts
+++ b/packages/core/src/services/TranslationService.ts
@@ -293,14 +293,14 @@ export class TranslationService {
   };
 
   private isFetchNeeded(lang: string) {
-    const isDevMode = this.properties.config.mode === 'development';
+    const isDevMode = this.properties.mode === 'development';
     const dataPresent = this.translationsCache.get(lang) !== undefined;
     const devFetched = Boolean(this.fetchedDev[lang]);
     return (isDevMode && !devFetched) || !dataPresent;
   }
 
   private async fetchTranslations(lang: string) {
-    const isDevMode = this.properties.config.mode === 'development';
+    const isDevMode = this.properties.mode === 'development';
     if (isDevMode) {
       return await this.fetchTranslationsDevelopment(lang);
     } else {