diff --git a/config/paths.js b/config/paths.js
index fe1d96a2..ed16c68b 100644
--- a/config/paths.js
+++ b/config/paths.js
@@ -1,10 +1,23 @@
+// @flow strict
 const path = require('path');
 const fs = require('fs');
 
 const appDirectory = fs.realpathSync(process.cwd());
 const resolveApp = (relativePath) => path.resolve(appDirectory, relativePath);
 
-const paths = {
+type PathsType = {
+  clientBuild: string,
+  serverBuild: string,
+  dotenv: string,
+  src: string,
+  srcClient: string,
+  srcServer: string,
+  srcApp: string,
+  publicPath: string,
+  resolveModules?: Array<string>
+};
+
+const paths: PathsType = {
   clientBuild: resolveApp('build/client'),
   serverBuild: resolveApp('build/server'),
   dotenv: resolveApp('.env'),
diff --git a/src/server/index.js b/src/server/index.js
index 06aa19a4..31a1241d 100644
--- a/src/server/index.js
+++ b/src/server/index.js
@@ -1,24 +1,35 @@
-// eslint-disable-next-line import/no-extraneous-dependencies
+// @flow strict
 import express from 'express';
+import type {
+  $Application,
+  $Request,
+  $Response,
+  NextFunction,
+} from 'express';
 import cors from 'cors';
 import path from 'path';
 import chalk from 'chalk';
+// "express-manifest-helpers" has not compatible Flow version
+// $FlowIgnoreMe
 import manifestHelpers from 'express-manifest-helpers';
 import bodyParser from 'body-parser';
 
-import serverRender from './render';
-import paths from '../../config/paths';
 import store from '@/store';
-
+// "paths" isn't been transpiled, so it can be ignored
+// $FlowIgnoreMe
+import paths from '../../config/paths';
+import serverRender from './render';
+// "dotenv" has not compatible Flow version
+// $FlowFixMe
 require('dotenv').config();
 
-const app = express();
+const app: $Application = express();
 
 // Use Nginx or Apache to serve static assets in production or remove the if() around the following
 // lines to use the express.static middleware to serve assets for production (not recommended!)
 if (process.env.NODE_ENV === 'development') {
   app.use(paths.publicPath, express.static(path.join(paths.clientBuild, paths.publicPath)));
-  app.use('/favicon.ico', (req, res) => {
+  app.use('/favicon.ico', (req: $Request, res: $Response): void => {
     res.send('');
   });
 }
@@ -27,8 +38,10 @@ app.use(cors());
 
 app.use(bodyParser.json());
 
-app.use((req, res, next) => {
-  req.store =store;
+app.use((req: $Request, res: $Response, next: NextFunction) => {
+  // "store" doesn't exists on express$Request, so we can just ignore it
+  // $FlowIgnore
+  req.store = store;
   return next();
 });
 
@@ -43,7 +56,7 @@ app.use(
 app.use(serverRender());
 
 // eslint-disable-next-line no-unused-vars
-app.use((err, req, res, next) => {
+app.use((err: Error, req: $Request, res: $Response, next: NextFunction): $Response => {
   return res.status(404).json({
     status: 'error',
     message: err.message,
@@ -66,7 +79,7 @@ app.use((err, req, res, next) => {
   });
 });
 
-app.listen(process.env.PORT || 8500, () => {
+app.listen(process.env.PORT || 8500, (): void => {
   // eslint-disable-next-line no-console
   console.log(
     `[${new Date().toISOString()}]`,