diff --git a/casdk-docs/docs/tutorial-extras/configuration.md b/casdk-docs/docs/tutorial-extras/configuration.md
index c65aa44f2..e7a12756f 100644
--- a/casdk-docs/docs/tutorial-extras/configuration.md
+++ b/casdk-docs/docs/tutorial-extras/configuration.md
@@ -202,6 +202,11 @@ where the assembly `CarbonAware.WebApi.dll` is located under `data-sources/json`
 directory. For instance, if the application is installed under `/app`, copy the
 file to `/app/data-sources/json`.
 
+Emission data in JSON is cached by default, it means original data would be handled
+even if JSON is updated.
+You need to set `DataSources__Configurations__JSON__CacheJsonData=false`
+if you want to handle updated data.
+
 ```sh
 cp <mydir>/mycustomfile.json /app/data-sources/json
 export DataSources__Configurations=Json
diff --git a/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/mock/JsonDataSourceMocker.cs b/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/mock/JsonDataSourceMocker.cs
index 5e09ba3de..808e3df9b 100644
--- a/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/mock/JsonDataSourceMocker.cs
+++ b/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/mock/JsonDataSourceMocker.cs
@@ -4,7 +4,7 @@
 using System.Text.Json;
 
 namespace CarbonAware.DataSources.Json.Mocks;
-internal class JsonDataSourceMocker : IDataSourceMocker
+public class JsonDataSourceMocker : IDataSourceMocker
 {
     public JsonDataSourceMocker() { }
 
diff --git a/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/src/Configuration/JsonDataSourceConfiguration.cs b/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/src/Configuration/JsonDataSourceConfiguration.cs
index 2c69e6be8..b54a3116d 100644
--- a/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/src/Configuration/JsonDataSourceConfiguration.cs
+++ b/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/src/Configuration/JsonDataSourceConfiguration.cs
@@ -30,11 +30,14 @@ public string DataFileLocation
         }
     }
 
+    public bool CacheJsonData { get; set; }
+
     public JsonDataSourceConfiguration()
     {
         var assemblyPath = Assembly.GetExecutingAssembly().Location;
         assemblyDirectory = Path.GetDirectoryName(assemblyPath)!;
         DataFileLocation = DefaultDataFile;
+        CacheJsonData = true;
     }
 
     private static bool IsValidDirPath(string fileName)
diff --git a/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/src/JsonDataSource.cs b/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/src/JsonDataSource.cs
index c62735dcb..c4943f558 100644
--- a/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/src/JsonDataSource.cs
+++ b/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/src/JsonDataSource.cs
@@ -104,11 +104,11 @@ private IEnumerable<EmissionsData> FilterByLocation(IEnumerable<EmissionsData> d
         }
         using Stream stream = GetStreamFromFileLocation();
         var jsonObject = await JsonSerializer.DeserializeAsync<EmissionsJsonFile>(stream);
-        if (_emissionsData is null || !_emissionsData.Any())
+        if (_configuration.CacheJsonData && (_emissionsData is null || !_emissionsData.Any()))
         {
             _emissionsData = jsonObject?.Emissions;
         }
-        return _emissionsData;
+        return jsonObject?.Emissions;
     }
 
     private Stream GetStreamFromFileLocation()
diff --git a/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/test/CarbonAware.DataSources.Json.Tests.csproj b/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/test/CarbonAware.DataSources.Json.Tests.csproj
index 065ebeee5..c54355685 100644
--- a/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/test/CarbonAware.DataSources.Json.Tests.csproj
+++ b/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/test/CarbonAware.DataSources.Json.Tests.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>net8.0</TargetFramework>
@@ -8,10 +8,10 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk"/>
-    <PackageReference Include="Moq"/>
-    <PackageReference Include="NUnit"/>
-    <PackageReference Include="NUnit3TestAdapter"/>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" />
+    <PackageReference Include="Moq" />
+    <PackageReference Include="NUnit" />
+    <PackageReference Include="NUnit3TestAdapter" />
     <PackageReference Include="coverlet.collector">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
@@ -23,6 +23,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <ProjectReference Include="..\mock\CarbonAware.DataSources.Json.Mocks.csproj" />
     <ProjectReference Include="..\src\CarbonAware.DataSources.Json.csproj" />
   </ItemGroup>
 
diff --git a/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/test/JsonDataSourceTests.cs b/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/test/JsonDataSourceTests.cs
index 4e204cec3..68ea73e24 100644
--- a/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/test/JsonDataSourceTests.cs
+++ b/src/CarbonAware.DataSources/CarbonAware.DataSources.Json/test/JsonDataSourceTests.cs
@@ -9,6 +9,7 @@
 using Moq.Protected;
 using Microsoft.Extensions.Options;
 using CarbonAware.DataSources.Json.Configuration;
+using CarbonAware.DataSources.Json.Mocks;
 
 namespace CarbonAware.DataSources.Json.Tests;
 
@@ -105,6 +106,56 @@ public async Task GetCarbonIntensityAsync_ReturnsEmptyEmissionData()
         Assert.That(!result.Any(), Is.True);
     }
 
+    [TestCase(true, TestName = "Test JsonDataSource with caching")]
+    [TestCase(false, TestName = "Test JsonDataSource without caching")]
+    public async Task GetCarbonIntensityAsync_CacheEmissionData(bool cache)
+    {
+        var logger = Mock.Of<ILogger<JsonDataSource>>();
+
+        var monitor = new Mock<IOptionsMonitor<JsonDataSourceConfiguration>>();
+        var config = new JsonDataSourceConfiguration
+        {
+            CacheJsonData = cache
+        };
+        monitor.Setup(m => m.CurrentValue).Returns(config);
+        var dataSource = new JsonDataSource(logger, monitor.Object);
+
+        JsonDataSourceMocker dsMocker = new();
+
+        var today = DateTimeOffset.Now;
+        var todayEnd = today.AddMinutes(30);
+        var todayLocation = new Location() { Name = "japan" };
+        dsMocker.SetupDataMock(today, todayEnd, todayLocation.Name);
+        var result1 = await dataSource.GetCarbonIntensityAsync(todayLocation, today, todayEnd);
+        Assert.AreEqual(1, result1.Count());
+        foreach (var r in result1)
+        {
+            Assert.AreEqual(r.Location, todayLocation.Name);
+        }
+
+        var yesterday = today.AddDays(-1);
+        var yesterdayEnd = yesterday.AddMinutes(30);
+        var yesterdayLocation = new Location() { Name = "uk" };
+        dsMocker.SetupDataMock(yesterday, yesterdayEnd, yesterdayLocation.Name);
+        if (cache)
+        {
+            var result2 = await dataSource.GetCarbonIntensityAsync(todayLocation, today, todayEnd);
+            Assert.AreEqual(1, result2.Count());
+            foreach (var r in result2)
+            {
+                Assert.AreEqual(r.Location, todayLocation.Name);
+            }
+        } else
+        {
+            var result2 = await dataSource.GetCarbonIntensityAsync(yesterdayLocation, yesterday, yesterdayEnd);
+            Assert.AreEqual(1, result2.Count());
+            foreach (var r in result2)
+            {
+                Assert.AreEqual(r.Location, yesterdayLocation.Name);
+            }
+        }
+    }
+
     private Mock<JsonDataSource> SetupMockDataSource() {
         var logger = Mock.Of<ILogger<JsonDataSource>>();
         var monitor = Mock.Of<IOptionsMonitor<JsonDataSourceConfiguration>>();