diff --git a/passport.js b/passport.js
new file mode 100644
index 0000000000..073111a7fa
--- /dev/null
+++ b/passport.js
@@ -0,0 +1,223 @@
+// Import required modules
+const passport = require('passport');
+const _ = require('lodash');
+const moment = require('moment');
+const axios = require('axios');
+const User = require('../models/User');
+
+// Serialize and deserialize user
+passport.serializeUser((user, done) => {
+  done(null, user.id);
+});
+
+passport.deserializeUser(async (id, done) => {
+  try {
+    const user = await User.findById(id);
+    done(null, user);
+  } catch (error) {
+    done(error);
+  }
+});
+
+// Common function to handle different services
+const handleService = async (req, accessToken, refreshToken, profile, done) => {
+  try {
+    if (req.user) {
+      const existingUser = await User.findOne({ [`${profile.provider}`]: profile.id });
+      if (existingUser) {
+        req.flash('errors', { msg: `There is already a ${_.startCase(profile.provider)} account that belongs to you. Sign in with that account or delete it, then link it with your current account.` });
+        return done(null, existingUser);
+      }
+      const user = await User.findById(req.user.id);
+      user[`${profile.provider}`] = profile.id;
+      user.tokens.push({ kind: `${profile.provider}`, accessToken });
+      user.profile.name = user.profile.name || profile.displayName;
+      user.profile.picture = user.profile.picture || profile.photos[0].value;
+      await user.save();
+      req.flash('info', { msg: `${_.startCase(profile.provider)} account has been linked.` });
+      return done(null, user);
+    }
+    const existingUser = await User.findOne({ [`${profile.provider}`]: profile.id });
+    if (existingUser) {
+      return done(null, existingUser);
+    }
+    const existingEmailUser = await User.findOne({ email: profile.emails[0].value });
+    if (existingEmailUser) {
+      req.flash('errors', { msg: `There is already an account using this email address. Sign in to that account and link it with ${_.startCase(profile.provider)} manually from Account Settings.` });
+      return done(null, existingEmailUser);
+    }
+    const user = new User();
+    user.email = profile.emails[0].value;
+    user[`${profile.provider}`] = profile.id;
+    user.tokens.push({ kind: `${profile.provider}`, accessToken });
+    user.profile.name = profile.displayName;
+    user.profile.picture = profile.photos[0].value;
+    await user.save();
+    return done(null, user);
+  } catch (err) {
+    return done(err);
+  }
+};
+
+// Export common function
+exports.handleService = handleService;
+
+// Import required modules
+const passport = require('passport');
+const { handleService } = require('./passportUtils');
+const User = require('../models/User');
+
+// Sign in with Facebook
+passport.use(new FacebookStrategy({
+  clientID: process.env.FACEBOOK_ID,
+  clientSecret: process.env.FACEBOOK_SECRET,
+  callbackURL: `${process.env.BASE_URL}/auth/facebook/callback`,
+  profileFields: ['name', 'email', 'link', 'locale', 'timezone', 'gender'],
+  passReqToCallback: true
+}, async (req, accessToken, refreshToken, profile, done) => {
+  try {
+    await handleService(req, accessToken, refreshToken, profile, done);
+  } catch (err) {
+    return done(err);
+  }
+}));
+
+// Sign in with Google
+passport.use(new GoogleStrategy({
+  clientID: process.env.GOOGLE_ID,
+  clientSecret: process.env.GOOGLE_SECRET,
+  callbackURL: '/auth/google/callback',
+  passReqToCallback: true
+}, async (req, accessToken, refreshToken, params, profile, done) => {
+  try {
+    await handleService(req, accessToken, refreshToken, profile, done);
+  } catch (err) {
+    return done(err);
+  }
+}));
+
+// Sign in with Twitter
+passport.use(new TwitterStrategy({
+  consumerKey: process.env.TWITTER_KEY,
+  consumerSecret: process.env.TWITTER_SECRET,
+  callbackURL: `${process.env.BASE_URL}/auth/twitter/callback`,
+  passReqToCallback: true
+}, async (req, accessToken, tokenSecret, profile, done) => {
+  try {
+    await handleService(req, accessToken, tokenSecret, profile, done);
+  } catch (err) {
+    return done(err);
+  }
+}));
+
+// Sign in with LinkedIn
+passport.use(new LinkedInStrategy({
+  clientID: process.env.LINKEDIN_ID,
+  clientSecret: process.env.LINKEDIN_SECRET,
+  callbackURL: `${process.env.BASE_URL}/auth/linkedin/callback`,
+  scope: ['r_liteprofile', 'r_emailaddress'],
+  passReqToCallback: true
+}, async (req, accessToken, refreshToken, profile, done) => {
+  try {
+    await handleService(req, accessToken, refreshToken, profile, done);
+  } catch (err) {
+    return done(err);
+  }
+}));
+
+// Sign in with GitHub
+passport.use(new GitHubStrategy({
+  clientID: process.env.GITHUB_ID,
+  clientSecret: process.env.GITHUB_SECRET,
+  callbackURL: `${process.env.BASE_URL}/auth/github/callback`,
+  passReqToCallback: true,
+  scope: ['user:email']
+}, async (req, accessToken, refreshToken, profile, done) => {
+  try {
+    await handleService(req, accessToken, refreshToken, profile, done);
+  } catch (err) {
+    return done(err);
+  }
+}));
+
+// Sign in with Snapchat
+passport.use(new SnapchatStrategy({
+  clientID: process.env.SNAPCHAT_ID,
+  clientSecret: process.env.SNAPCHAT_SECRET,
+  callbackURL: '/auth/snapchat/callback',
+  profileFields: ['id', 'displayName', 'bitmoji'],
+  scope: ['user.display_name', 'user.bitmoji.avatar'],
+  passReqToCallback: true
+}, async (req, accessToken, refreshToken, profile, done) => {
+  try {
+    await handleService(req, accessToken, refreshToken, profile, done);
+  } catch (err) {
+    return done(err);
+  }
+}));
+
+// Sign in with Twitch
+passport.use(new TwitchStrategy({
+  clientID: process.env.TWITCH_CLIENT_ID,
+  clientSecret: process.env.TWITCH_CLIENT_SECRET,
+  callbackURL: `${process.env.BASE_URL}/auth/twitch/callback`,
+  scope: ['user_read', 'chat:read', 'chat:edit', 'whispers:read', 'whispers:edit', 'user:read:email'],
+  passReqToCallback: true
+}, async (req, accessToken, refreshToken, params, profile, done) => {
+  try {
+    await handleService(req, accessToken, refreshToken, profile, done);
+  } catch (err) {
+    return done(err);
+  }
+}));
+
+// Sign in with Steam
+passport.use(new SteamOpenIdStrategy({
+  apiKey: process.env.STEAM_KEY,
+  returnURL: `${process.env.BASE_URL}/auth/steam/callback`,
+  profile: true,
+}, async (req, identifier, profile, done) => {
+  try {
+    const steamId = identifier.match(/\d+$/)[0];
+    const profileURL = `http://api.steampowered.com/ISteamUser/GetPlayerSummaries/v0002/?key=${process.env.STEAM_KEY}&steamids=${steamId}`;
+    if (req.user) {
+      const existingUser = await User.findOne({ steam: steamId });
+      if (existingUser) {
+        req.flash('errors', { msg: 'There is already an account associated with the SteamID. Sign in with that account or delete it, then link it with your current account.' });
+        return done(null, existingUser);
+      }
+      const user = await User.findById(req.user.id);
+      user.steam = steamId;
+      user.tokens.push({ kind: 'steam', accessToken: steamId });
+      try {
+        const res = await axios.get(profileURL);
+        const profileData = res.data.response.players[0];
+        user.profile.name = user.profile.name || profileData.personaname;
+        user.profile.picture = user.profile.picture || profileData.avatarmedium;
+        await user.save();
+        return done(null, user);
+      } catch (err) {
+        console.log(err);
+        await user.save();
+        return done(err, user);
+      }
+    } else {
+      try {
+        const { data } = await axios.get(profileURL);
+        const profileData = data.response.players[0];
+        const user = new User();
+        user.steam = steamId;
+        user.email = `${steamId}@steam.com`; // steam does not disclose emails, prevent duplicate keys
+        user.tokens.push({ kind: 'steam', accessToken: steamId });
+        user.profile.name = profileData.personaname;
+        user.profile.picture = profileData.avatarmedium;
+        await user.save();
+        return done(null, user);
+      } catch (err) {
+        return done(err, null);
+      }
+    }
+  } catch (err) {
+    return done(err);
+  }
+}));
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