diff --git a/HearthDb.CardDefsDownloader/HearthDb.CardDefsDownloader.csproj b/HearthDb.CardDefsDownloader/HearthDb.CardDefsDownloader.csproj
new file mode 100644
index 0000000..918adb6
--- /dev/null
+++ b/HearthDb.CardDefsDownloader/HearthDb.CardDefsDownloader.csproj
@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>netcoreapp3.1</TargetFramework>
+        <LangVersion>8</LangVersion>
+        <OutputType>Exe</OutputType>
+    </PropertyGroup>
+
+</Project>
diff --git a/HearthDb.CardDefsDownloader/Program.cs b/HearthDb.CardDefsDownloader/Program.cs
new file mode 100644
index 0000000..391e55d
--- /dev/null
+++ b/HearthDb.CardDefsDownloader/Program.cs
@@ -0,0 +1,31 @@
+using System;
+using System.IO;
+using System.Net;
+using System.Net.Http;
+using System.Net.Http.Headers;
+
+namespace HearthDb.CardDefsDownloader
+{
+    class Program
+    {
+        static void Main(string[] args)
+        {
+	        Console.WriteLine(args[0]);
+            var httpClient = new HttpClient(new HttpClientHandler { AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate });
+
+			// CardDefs.base.xml contains non localized tags and enUS tag
+	        // Other languages can be found under e.g. CardDefs.deDE.xml
+            using var request = new HttpRequestMessage(HttpMethod.Get, "https://api.hearthstonejson.com/v1/latest/CardDefs.base.xml");
+            request.Headers.AcceptEncoding.Add(new StringWithQualityHeaderValue("gzip"));
+            request.Headers.AcceptEncoding.Add(new StringWithQualityHeaderValue("deflate"));
+
+			var response = httpClient.SendAsync(request).Result;
+			var data = response.Content.ReadAsStringAsync().Result;
+			File.WriteAllText(Path.Combine(args[0], "CardDefs.base.xml"), data);
+
+			var etag = response.Headers.ETag.Tag;
+			var lastModified = response.Content.Headers.LastModified;
+			File.WriteAllText(Path.Combine(args[0], "CardDefs.base.etag"), $"{etag}\n{lastModified.ToString()}");
+        }
+    }
+}
\ No newline at end of file
diff --git a/HearthDb.Tests/CardDefsLoadTest.cs b/HearthDb.Tests/CardDefsLoadTest.cs
index f6724ee..0a2c805 100644
--- a/HearthDb.Tests/CardDefsLoadTest.cs
+++ b/HearthDb.Tests/CardDefsLoadTest.cs
@@ -36,5 +36,11 @@ public void LoadCards_CorrectlyAssemblesData()
             Assert.AreEqual("Flame Lance", Cards.All["AT_001"].GetLocName(Locale.enUS));
             Assert.AreEqual("Flammenlanze", Cards.All["AT_001"].GetLocName(Locale.deDE));
         }
+
+        [TestMethod]
+        public void HasEtag()
+        {
+            Assert.IsNotNull(Cards.GetBaseCardDefsETag());
+        }
     }
 }
\ No newline at end of file
diff --git a/HearthDb.sln b/HearthDb.sln
index 5773565..286e4c3 100644
--- a/HearthDb.sln
+++ b/HearthDb.sln
@@ -11,6 +11,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "HearthDb.EnumsGenerator", "
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "HearthDb.Tests", "HearthDb.Tests\HearthDb.Tests.csproj", "{875316D1-C4C3-48BD-BDAE-3727269B2A67}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "HearthDb.CardDefsDownloader", "HearthDb.CardDefsDownloader\HearthDb.CardDefsDownloader.csproj", "{92DBA109-DF71-4874-827A-20B00EABB57D}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -51,6 +53,14 @@ Global
 		{875316D1-C4C3-48BD-BDAE-3727269B2A67}.Release|Any CPU.Build.0 = Release|Any CPU
 		{875316D1-C4C3-48BD-BDAE-3727269B2A67}.Release|x86.ActiveCfg = Release|Any CPU
 		{875316D1-C4C3-48BD-BDAE-3727269B2A67}.Release|x86.Build.0 = Release|Any CPU
+		{92DBA109-DF71-4874-827A-20B00EABB57D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{92DBA109-DF71-4874-827A-20B00EABB57D}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{92DBA109-DF71-4874-827A-20B00EABB57D}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{92DBA109-DF71-4874-827A-20B00EABB57D}.Debug|x86.Build.0 = Debug|Any CPU
+		{92DBA109-DF71-4874-827A-20B00EABB57D}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{92DBA109-DF71-4874-827A-20B00EABB57D}.Release|Any CPU.Build.0 = Release|Any CPU
+		{92DBA109-DF71-4874-827A-20B00EABB57D}.Release|x86.ActiveCfg = Release|Any CPU
+		{92DBA109-DF71-4874-827A-20B00EABB57D}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
diff --git a/HearthDb/Cards.cs b/HearthDb/Cards.cs
index 618da68..633ac12 100644
--- a/HearthDb/Cards.cs
+++ b/HearthDb/Cards.cs
@@ -41,6 +41,21 @@ public static class Cards
 
 		public static string Build { get; private set; }
 
+		private static (string Etag, string LastModified)? _baseCardDefsEtag;
+		public static (string Etag, string LastModified) GetBaseCardDefsETag()
+		{
+			if(_baseCardDefsEtag == null)
+			{
+				using var stream = Assembly.GetExecutingAssembly().GetManifestResourceStream("HearthDb.CardDefs.base.etag");
+				if (stream == null)
+					return (null, null);
+				using var reader = new StreamReader(stream);
+				var text = reader.ReadToEnd().Split('\n');
+				_baseCardDefsEtag = (text[0], text[1]);
+			}
+			return _baseCardDefsEtag.Value;
+		}
+
 		static Cards()
 		{
 			if(Config.AutoLoadCardDefs)
diff --git a/HearthDb/HearthDb.csproj b/HearthDb/HearthDb.csproj
index cd82c23..aa2c024 100644
--- a/HearthDb/HearthDb.csproj
+++ b/HearthDb/HearthDb.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk" DefaultsTargets="DownloadBaseData">
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
@@ -20,6 +20,9 @@
         <EmbeddedResource Include="hsdata/CardDefs.base.xml">
             <LogicalName>$(RootNamespace).CardDefs.base.xml</LogicalName>
         </EmbeddedResource>
+        <EmbeddedResource Include="hsdata/CardDefs.base.etag">
+            <LogicalName>$(RootNamespace).CardDefs.base.etag</LogicalName>
+        </EmbeddedResource>
     </ItemGroup>
 
     <ItemGroup>
@@ -29,15 +32,12 @@
     </ItemGroup>
 
   <PropertyGroup>
-    <!-- CardDefs.base.xml contains non localized tags and enUS tag -->
-    <!-- Other languages can be found under e.g. CardDefs.deDE.xml -->
     <BaseDataUrl>https://api.hearthstonejson.com/v1/latest/CardDefs.base.xml</BaseDataUrl>
   </PropertyGroup>
 
     <Target Name="DownloadBaseData" BeforeTargets="PreBuildEvent">
-        <DownloadFile SourceUrl="$(BaseDataUrl)" DestinationFolder="$(MSBuildProjectDirectory)/hsdata" SkipUnchangedFiles="true">
-            <Output TaskParameter="DownloadedFile" ItemName="Content" />
-        </DownloadFile>
+      <Exec Command="msbuild $(SolutionDir)HearthDb.CardDefsDownloader\HearthDb.CardDefsDownloader.csproj"/>
+      <Exec Command="$(SolutionDir)HearthDb.CardDefsDownloader\bin\Debug\netcoreapp3.1\HearthDb.CardDefsDownloader.exe $(SolutionDir)\HearthDb\hsdata"/>
     </Target>
 
 </Project>