diff --git a/src/App/Services/MobilePlatformUtilsService.cs b/src/App/Services/MobilePlatformUtilsService.cs
index f45bc8a79..5a78065b9 100644
--- a/src/App/Services/MobilePlatformUtilsService.cs
+++ b/src/App/Services/MobilePlatformUtilsService.cs
@@ -1,5 +1,6 @@
 using Bit.App.Abstractions;
 using Bit.App.Models;
+using Bit.Core.Abstractions;
 using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
@@ -8,7 +9,7 @@ using Xamarin.Forms;
 
 namespace Bit.App.Services
 {
-    public class MobilePlatformUtilsService
+    public class MobilePlatformUtilsService : IPlatformUtilsService
     {
         private static readonly Random _random = new Random();
 
diff --git a/src/Core/Abstractions/IPlatformUtilsService.cs b/src/Core/Abstractions/IPlatformUtilsService.cs
new file mode 100644
index 000000000..1c21ad28d
--- /dev/null
+++ b/src/Core/Abstractions/IPlatformUtilsService.cs
@@ -0,0 +1,28 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Bit.Core.Enums;
+
+namespace Bit.Core.Abstractions
+{
+    public interface IPlatformUtilsService
+    {
+        string IdentityClientId { get; }
+
+        Task CopyToClipboardAsync(string text, Dictionary<string, object> options = null);
+        string GetApplicationVersion();
+        DeviceType GetDevice();
+        string GetDeviceString();
+        bool IsDev();
+        bool IsSelfHost();
+        bool IsViewOpen();
+        void LaunchUri(string uri, Dictionary<string, object> options = null);
+        int? LockTimeout();
+        Task<string> ReadFromClipboardAsync(Dictionary<string, object> options = null);
+        void SaveFile();
+        Task<bool> ShowDialogAsync(string text, string title = null, string confirmText = null,
+            string cancelText = null, string type = null);
+        void ShowToast(string type, string title, string text, Dictionary<string, object> options = null);
+        void ShowToast(string type, string title, string[] text, Dictionary<string, object> options = null);
+        bool SupportsU2f();
+    }
+}
\ No newline at end of file
diff --git a/src/Core/Exceptions/ApiException.cs b/src/Core/Exceptions/ApiException.cs
new file mode 100644
index 000000000..2b46d55ec
--- /dev/null
+++ b/src/Core/Exceptions/ApiException.cs
@@ -0,0 +1,14 @@
+using Bit.Core.Models.Response;
+using System;
+
+namespace Bit.Core.Exceptions
+{
+    public class ApiException : Exception
+    {
+        public ApiException(ErrorResponse error)
+            : base("An API error has occurred.")
+        { }
+
+        public ErrorResponse Error { get; set; }
+    }
+}
diff --git a/src/Core/Models/Domain/EnvironmentUrls.cs b/src/Core/Models/Domain/EnvironmentUrls.cs
new file mode 100644
index 000000000..6f6b43577
--- /dev/null
+++ b/src/Core/Models/Domain/EnvironmentUrls.cs
@@ -0,0 +1,9 @@
+namespace Bit.Core.Models.Domain
+{
+    public class EnvironmentUrls
+    {
+        public string Base { get; set; }
+        public string Api { get; set; }
+        public string Identity { get; set; }
+    }
+}
diff --git a/src/Core/Models/Request/DeviceRequestModels.cs b/src/Core/Models/Request/DeviceRequestModels.cs
new file mode 100644
index 000000000..ecc9bf90c
--- /dev/null
+++ b/src/Core/Models/Request/DeviceRequestModels.cs
@@ -0,0 +1,21 @@
+using Bit.Core.Abstractions;
+using Bit.Core.Enums;
+
+namespace Bit.Core.Models.Request
+{
+    public class DeviceRequest
+    {
+        public DeviceRequest(string appId, IPlatformUtilsService platformUtilsService)
+        {
+            Type = platformUtilsService.GetDevice();
+            Name = platformUtilsService.GetDeviceString();
+            Identifier = appId;
+            PushToken = null; // TODO?
+        }
+
+        public DeviceType? Type { get; set; }
+        public string Name { get; set; }
+        public string Identifier { get; set; }
+        public string PushToken { get; set; }
+    }
+}
diff --git a/src/Core/Models/Request/TokenRequest.cs b/src/Core/Models/Request/TokenRequest.cs
new file mode 100644
index 000000000..7dd8913e6
--- /dev/null
+++ b/src/Core/Models/Request/TokenRequest.cs
@@ -0,0 +1,17 @@
+using Bit.Core.Enums;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Bit.Core.Models.Request
+{
+    public class TokenRequest
+    {
+        public string Email { get; set; }
+        public string MasterPasswordHash { get; set; }
+        public string Token { get; set; }
+        public TwoFactorProviderType Provider { get; set; }
+        public bool Remember { get; set; }
+        public DeviceRequest Device { get; set; }
+    }
+}
diff --git a/src/Core/Models/Response/ErrorResponse.cs b/src/Core/Models/Response/ErrorResponse.cs
new file mode 100644
index 000000000..188134dae
--- /dev/null
+++ b/src/Core/Models/Response/ErrorResponse.cs
@@ -0,0 +1,62 @@
+using Newtonsoft.Json.Linq;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net;
+
+namespace Bit.Core.Models.Response
+{
+    public class ErrorResponse
+    {
+        public ErrorResponse(JObject response, HttpStatusCode status, bool identityResponse = false)
+        {
+            JObject errorModel = null;
+            if(response != null)
+            {
+                var responseErrorModel = response.GetValue("ErrorModel", StringComparison.OrdinalIgnoreCase);
+                if(responseErrorModel != null && identityResponse)
+                {
+                    errorModel = responseErrorModel.Value<JObject>(); ;
+                }
+                else
+                {
+                    errorModel = response;
+                }
+            }
+            if(errorModel != null)
+            {
+                Message = errorModel.GetValue("Message", StringComparison.OrdinalIgnoreCase)?.Value<string>();
+                ValidationErrors = errorModel.GetValue("ValidationErrors", StringComparison.OrdinalIgnoreCase)
+                    ?.Value<Dictionary<string, List<string>>>();
+            }
+            else
+            {
+                if((int)status == 429)
+                {
+                    Message = "Rate limit exceeded. Try again later.";
+                }
+            }
+            StatusCode = status;
+        }
+
+        public string Message { get; set; }
+        public Dictionary<string, List<string>> ValidationErrors { get; set; }
+        public HttpStatusCode StatusCode { get; set; }
+
+        public string GetSingleMessage()
+        {
+            if(ValidationErrors == null)
+            {
+                return Message;
+            }
+            foreach(var error in ValidationErrors)
+            {
+                if(error.Value?.Any() ?? false)
+                {
+                    return error.Value[0];
+                }
+            }
+            return Message;
+        }
+    }
+}
diff --git a/src/Core/Models/Response/IdentityTokenResponse.cs b/src/Core/Models/Response/IdentityTokenResponse.cs
new file mode 100644
index 000000000..c2c8e5ee9
--- /dev/null
+++ b/src/Core/Models/Response/IdentityTokenResponse.cs
@@ -0,0 +1,13 @@
+namespace Bit.Core.Models.Response
+{
+    public class IdentityTokenResponse
+    {
+        public string AccessToken { get; set; }
+        public string ExpiresIn { get; set; }
+        public string RefreshToken { get; set; }
+        public string TokenType { get; set; }
+        public string PrivateKey { get; set; }
+        public string Key { get; set; }
+        public string TwoFactorToken { get; set; }
+    }
+}
diff --git a/src/Core/Models/Response/IdentityTwoFactorResponse.cs b/src/Core/Models/Response/IdentityTwoFactorResponse.cs
new file mode 100644
index 000000000..82f082e9e
--- /dev/null
+++ b/src/Core/Models/Response/IdentityTwoFactorResponse.cs
@@ -0,0 +1,11 @@
+using Bit.Core.Enums;
+using System.Collections.Generic;
+
+namespace Bit.Core.Models.Response
+{
+    public class IdentityTwoFactorResponse
+    {
+        public List<TwoFactorProviderType> TwoFactorProviders { get; set; }
+        public Dictionary<TwoFactorProviderType, Dictionary<string, object>> TwoFactorProviders2 { get; set; }
+    }
+}
diff --git a/src/Core/Services/ApiService.cs b/src/Core/Services/ApiService.cs
new file mode 100644
index 000000000..118fc4180
--- /dev/null
+++ b/src/Core/Services/ApiService.cs
@@ -0,0 +1,102 @@
+using Bit.Core.Abstractions;
+using Bit.Core.Exceptions;
+using Bit.Core.Models.Domain;
+using Bit.Core.Models.Response;
+using Newtonsoft.Json.Linq;
+using System;
+using System.Linq;
+using System.Net;
+using System.Net.Http;
+using System.Threading.Tasks;
+
+namespace Bit.Core.Services
+{
+    public class ApiService
+    {
+        private readonly HttpClient _httpClient = new HttpClient();
+        private readonly ITokenService _tokenService;
+        private readonly IPlatformUtilsService _platformUtilsService;
+
+        private string _deviceType;
+        private bool _usingBaseUrl = false;
+
+        public ApiService(
+            ITokenService tokenService,
+            IPlatformUtilsService platformUtilsService)
+        {
+            _tokenService = tokenService;
+            _platformUtilsService = platformUtilsService;
+        }
+
+        public bool UrlsSet { get; private set; }
+        public string ApiBaseUrl { get; set; }
+        public string IdentityBaseUrl { get; set; }
+
+        public void SetUrls(EnvironmentUrls urls)
+        {
+            UrlsSet = true;
+            if(!string.IsNullOrWhiteSpace(urls.Base))
+            {
+                _usingBaseUrl = true;
+                ApiBaseUrl = urls.Base + "/api";
+                IdentityBaseUrl = urls.Base + "/identity";
+                return;
+            }
+            if(!string.IsNullOrWhiteSpace(urls.Api) && !string.IsNullOrWhiteSpace(urls.Identity))
+            {
+                ApiBaseUrl = urls.Api;
+                IdentityBaseUrl = urls.Identity;
+                return;
+            }
+            // Local Dev
+            //ApiBaseUrl = "http://localhost:4000";
+            //IdentityBaseUrl = "http://localhost:33656";
+            // Production
+            ApiBaseUrl = "https://api.bitwarden.com";
+            IdentityBaseUrl = "https://identity.bitwarden.com";
+        }
+
+        #region Auth APIs
+
+        public async Task<Tuple<IdentityTokenResponse, IdentityTwoFactorResponse>> PostIdentityTokenAsync()
+        {
+            var request = new HttpRequestMessage
+            {
+                RequestUri = new Uri(string.Concat(IdentityBaseUrl, "/connect/token")),
+                Method = HttpMethod.Post
+            };
+            request.Headers.Add("Content-Type", "application/x-www-form-urlencoded; charset=utf-8");
+            request.Headers.Add("Accept", "application/json");
+            request.Headers.Add("Device-Type", _deviceType);
+
+            var response = await _httpClient.SendAsync(request);
+            JObject responseJObject = null;
+            if(response.Headers.Contains("content-type") &&
+                response.Headers.GetValues("content-type").Any(h => h.Contains("application/json")))
+            {
+                var responseJsonString = await response.Content.ReadAsStringAsync();
+                responseJObject = JObject.Parse(responseJsonString);
+            }
+
+            if(responseJObject != null)
+            {
+                if(response.IsSuccessStatusCode)
+                {
+                    return new Tuple<IdentityTokenResponse, IdentityTwoFactorResponse>(
+                        responseJObject.ToObject<IdentityTokenResponse>(), null);
+                }
+                else if(response.StatusCode == HttpStatusCode.BadRequest &&
+                    responseJObject.ContainsKey("TwoFactorProviders2") &&
+                    responseJObject["TwoFactorProviders2"] != null &&
+                    responseJObject["TwoFactorProviders2"].HasValues)
+                {
+                    return new Tuple<IdentityTokenResponse, IdentityTwoFactorResponse>(
+                        null, responseJObject.ToObject<IdentityTwoFactorResponse>());
+                }
+            }
+            throw new ApiException(new ErrorResponse(responseJObject, response.StatusCode, true));
+        }
+
+        #endregion
+    }
+}