diff --git a/src/Core/Services/SyncService.cs b/src/Core/Services/SyncService.cs
new file mode 100644
index 000000000..e581c2d05
--- /dev/null
+++ b/src/Core/Services/SyncService.cs
@@ -0,0 +1,167 @@
+using Bit.Core.Abstractions;
+using Bit.Core.Models.Data;
+using Bit.Core.Models.Response;
+using Bit.Core.Utilities;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Bit.Core.Services
+{
+    public class SyncService
+    {
+        private const string Keys_LastSyncFormat = "lastSync_{0}";
+
+        private readonly IUserService _userService;
+        private readonly IApiService _apiService;
+        private readonly ISettingsService _settingsService;
+        private readonly IFolderService _folderService;
+        private readonly ICipherService _cipherService;
+        private readonly ICryptoService _cryptoService;
+        private readonly ICollectionService _collectionService;
+        private readonly IStorageService _storageService;
+        private readonly IMessagingService _messagingService;
+
+        public SyncService(
+            IUserService userService,
+            IApiService apiService,
+            ISettingsService settingsService,
+            IFolderService folderService,
+            ICipherService cipherService,
+            ICryptoService cryptoService,
+            ICollectionService collectionService,
+            IStorageService storageService,
+            IMessagingService messagingService)
+        {
+            _userService = userService;
+            _apiService = apiService;
+            _settingsService = settingsService;
+            _folderService = folderService;
+            _cipherService = cipherService;
+            _cryptoService = cryptoService;
+            _collectionService = collectionService;
+            _storageService = storageService;
+            _messagingService = messagingService;
+        }
+
+        public bool SyncInProgress { get; set; }
+
+        public async Task<DateTime?> GetLastSyncAsync()
+        {
+            var userId = await _userService.GetUserIdAsync();
+            if(userId == null)
+            {
+                return null;
+            }
+            return await _storageService.GetAsync<DateTime?>(string.Format(Keys_LastSyncFormat, userId));
+        }
+
+        public async Task SetLastSync(DateTime date)
+        {
+            var userId = await _userService.GetUserIdAsync();
+            if(userId == null)
+            {
+                return;
+            }
+            await _storageService.SaveAsync(string.Format(Keys_LastSyncFormat, userId), date);
+        }
+
+        // Helpers
+
+        private void SyncStarted()
+        {
+            SyncInProgress = true;
+            _messagingService.Send("syncStarted");
+        }
+
+        private bool SyncCompelted(bool successfully)
+        {
+            SyncInProgress = false;
+            _messagingService.Send("syncCompleted", new Dictionary<string, object> { ["successfully"] = successfully });
+            return successfully;
+        }
+
+        private async Task<Tuple<bool, bool>> NeedsSyncingAsync(bool forceSync)
+        {
+            if(forceSync)
+            {
+                return new Tuple<bool, bool>(true, false);
+            }
+            var lastSync = await GetLastSyncAsync();
+            if(lastSync == null || lastSync == DateTime.MinValue)
+            {
+                return new Tuple<bool, bool>(true, false);
+            }
+            try
+            {
+                var response = await _apiService.GetAccountRevisionDateAsync();
+                var d = CoreHelpers.Epoc.AddMilliseconds(response);
+                if(d <= lastSync.Value)
+                {
+                    return new Tuple<bool, bool>(false, false);
+                }
+                return new Tuple<bool, bool>(true, false);
+            }
+            catch
+            {
+                return new Tuple<bool, bool>(false, true);
+            }
+        }
+
+        private async Task SyncProfileAsync(ProfileResponse response)
+        {
+            var stamp = await _userService.GetSecurityStampAsync();
+            if(stamp != null && stamp != response.SecurityStamp)
+            {
+                // TODO logout callback
+                throw new Exception("Stamp has changed.");
+            }
+            await _cryptoService.SetEncKeyAsync(response.Key);
+            await _cryptoService.SetEncPrivateKeyAsync(response.PrivateKey);
+            await _cryptoService.SetOrgKeysAsync(response.Organizations);
+            await _userService.SetSecurityStampAsync(response.SecurityStamp);
+            var organizations = response.Organizations.ToDictionary(o => o.Id, o => new OrganizationData(o));
+            await _userService.ReplaceOrganizationsAsync(organizations);
+        }
+
+        private async Task SyncFoldersAsync(string userId, List<FolderResponse> response)
+        {
+            var folders = response.ToDictionary(f => f.Id, f => new FolderData(f, userId));
+            await _folderService.ReplaceAsync(folders);
+        }
+
+        private async Task SyncCollectionsAsync(List<CollectionDetailsResponse> response)
+        {
+            var collections = response.ToDictionary(c => c.Id, c => new CollectionData(c));
+            await _collectionService.ReplaceAsync(collections);
+        }
+
+        private async Task SyncCiphersAsync(string userId, List<CipherResponse> response)
+        {
+            var ciphers = response.ToDictionary(c => c.Id, c => new CipherData(c, userId));
+            await _cipherService.ReplaceAsync(ciphers);
+        }
+
+        private async Task SyncSettingsAsync(string userId, DomainsResponse response)
+        {
+            var eqDomains = new List<List<string>>();
+            if(response != null && response.EquivalentDomains != null)
+            {
+                eqDomains = eqDomains.Concat(response.EquivalentDomains).ToList();
+            }
+            if(response != null && response.GlobalEquivalentDomains != null)
+            {
+                foreach(var global in response.GlobalEquivalentDomains)
+                {
+                    if(global.Domains.Any())
+                    {
+                        eqDomains.Add(global.Domains);
+                    }
+                }
+            }
+            await _settingsService.SetEquivalentDomainsAsync(eqDomains);
+        }
+    }
+}