diff --git a/src/electron/Settings.ts b/src/electron/Settings.ts
index de010b9a3a..d09ac7fb62 100644
--- a/src/electron/Settings.ts
+++ b/src/electron/Settings.ts
@@ -5,11 +5,11 @@ import { userDataPath } from '../environment-remote';
 const debug = require('../preload-safe-debug')('Ferdium:Settings');
 
 export default class Settings {
-  type = '';
+  type: string = '';
 
-  defaultState: {};
+  defaultState: object;
 
-  @observable store = {};
+  @observable store: object = {};
 
   constructor(type: string, defaultState = {}) {
     this.type = type;
@@ -23,41 +23,41 @@ export default class Settings {
     }
   }
 
-  set(settings) {
+  set(settings: object): void {
     this.store = this._merge(settings);
 
     this._writeFile();
   }
 
-  get all() {
+  get all(): object {
     return this.store;
   }
 
-  get allSerialized() {
+  get allSerialized(): object {
     return toJS(this.store);
   }
 
-  get(key: string | number) {
+  get(key: string | number): any {
     return this.store[key];
   }
 
-  _merge(settings) {
+  _merge(settings: object): object {
     return Object.assign(this.defaultState, this.store, settings);
   }
 
-  _hydrate() {
+  _hydrate(): void {
     this.store = this._merge(readJsonSync(this.settingsFile));
     debug('Hydrate store', this.type, this.allSerialized);
   }
 
-  _writeFile() {
+  _writeFile(): void {
     outputJsonSync(this.settingsFile, this.store, {
       spaces: 2,
     });
     debug('Write settings file', this.type, this.allSerialized);
   }
 
-  get settingsFile() {
+  get settingsFile(): string {
     return userDataPath(
       'config',
       `${this.type === 'app' ? 'settings' : this.type}.json`,
diff --git a/src/electron/deepLinking.ts b/src/electron/deepLinking.ts
index 532bdd6fb0..36de1b1436 100644
--- a/src/electron/deepLinking.ts
+++ b/src/electron/deepLinking.ts
@@ -1,4 +1,9 @@
-export default function handleDeepLink(window, rawUrl) {
+import { BrowserWindow } from 'electron';
+
+export default function handleDeepLink(
+  window: BrowserWindow,
+  rawUrl: string,
+): void {
   const url = rawUrl.replace('ferdium://', '');
 
   if (!url) return;
diff --git a/src/electron/macOSPermissions.ts b/src/electron/macOSPermissions.ts
index 2415534e56..c9f22aecbd 100644
--- a/src/electron/macOSPermissions.ts
+++ b/src/electron/macOSPermissions.ts
@@ -35,7 +35,7 @@ function hasScreenCapturePermissionAlreadyBeenGranted(): boolean {
   return screenCaptureStatus === 'granted';
 }
 
-function createStatusFile() {
+function createStatusFile(): void {
   try {
     writeFileSync(filePath, '');
   } catch (error) {
@@ -48,7 +48,9 @@ function createStatusFile() {
   }
 }
 
-export const askFormacOSPermissions = async (mainWindow: BrowserWindow) => {
+export const askFormacOSPermissions = async (
+  mainWindow: BrowserWindow,
+): Promise<void> => {
   debug('Checking camera & microphone permissions');
   systemPreferences.askForMediaAccess('camera');
   systemPreferences.askForMediaAccess('microphone');
diff --git a/src/electron/windowUtils.ts b/src/electron/windowUtils.ts
index 1db1ff2464..9c9fd1b77c 100644
--- a/src/electron/windowUtils.ts
+++ b/src/electron/windowUtils.ts
@@ -1,6 +1,6 @@
 import { screen } from 'electron';
 
-export function isPositionValid(position: { x: number; y: number }) {
+export function isPositionValid(position: { x: number; y: number }): boolean {
   const displays = screen.getAllDisplays();
   const { x, y } = position;
   return displays.some(