diff --git a/CHANGELOG.md b/CHANGELOG.md
index 844ba4106e..654821f034 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 ### Fixes
 
+- Emit transaction.data inside contexts.trace.data ([#3936](https://github.com/getsentry/sentry-dotnet/pull/3936))
 - Native SIGSEGV errors resulting from managed NullReferenceExceptions are now suppressed on Android ([#3903](https://github.com/getsentry/sentry-dotnet/pull/3903))
 - OTel activities that are marked as not recorded are no longer sent to Sentry ([#3890](https://github.com/getsentry/sentry-dotnet/pull/3890))
 - Fixed envelopes with oversized attachments getting stuck in __processing ([#3938](https://github.com/getsentry/sentry-dotnet/pull/3938))
diff --git a/src/Sentry/IHasData.cs b/src/Sentry/IHasData.cs
new file mode 100644
index 0000000000..980f403731
--- /dev/null
+++ b/src/Sentry/IHasData.cs
@@ -0,0 +1,17 @@
+namespace Sentry;
+
+/// <summary>
+/// Implemented by objects that contain a map of untyped additional metadata.
+/// </summary>
+public interface IHasData
+{
+    /// <summary>
+    /// An arbitrary mapping of additional metadata to store with the event.
+    /// </summary>
+    IReadOnlyDictionary<string, object?> Data { get; }
+
+    /// <summary>
+    /// Sets an extra.
+    /// </summary>
+    void SetData(string key, object? value);
+}
diff --git a/src/Sentry/ISpanData.cs b/src/Sentry/ISpanData.cs
index 373ff75c34..3a475102b8 100644
--- a/src/Sentry/ISpanData.cs
+++ b/src/Sentry/ISpanData.cs
@@ -5,7 +5,7 @@ namespace Sentry;
 /// <summary>
 /// Immutable data belonging to a span.
 /// </summary>
-public interface ISpanData : ITraceContext, IHasTags, IHasExtra
+public interface ISpanData : ITraceContext, IHasData, IHasTags, IHasExtra
 {
     /// <summary>
     /// Start timestamp.
diff --git a/src/Sentry/Internal/NoOpSpan.cs b/src/Sentry/Internal/NoOpSpan.cs
index babecc4a4d..f6e49e5a2c 100644
--- a/src/Sentry/Internal/NoOpSpan.cs
+++ b/src/Sentry/Internal/NoOpSpan.cs
@@ -19,6 +19,7 @@ protected NoOpSpan()
     public bool? IsSampled => default;
     public IReadOnlyDictionary<string, string> Tags => ImmutableDictionary<string, string>.Empty;
     public IReadOnlyDictionary<string, object?> Extra => ImmutableDictionary<string, object?>.Empty;
+    public IReadOnlyDictionary<string, object?> Data => ImmutableDictionary<string, object?>.Empty;
     public DateTimeOffset StartTimestamp => default;
     public DateTimeOffset? EndTimestamp => default;
     public bool IsFinished => default;
@@ -71,6 +72,10 @@ public void SetExtra(string key, object? value)
     {
     }
 
+    public void SetData(string key, object? value)
+    {
+    }
+
     public SentryTraceHeader GetTraceHeader() => SentryTraceHeader.Empty;
 
     public IReadOnlyDictionary<string, Measurement> Measurements => ImmutableDictionary<string, Measurement>.Empty;
diff --git a/src/Sentry/Protocol/Trace.cs b/src/Sentry/Protocol/Trace.cs
index 289b2a4b08..8878aab170 100644
--- a/src/Sentry/Protocol/Trace.cs
+++ b/src/Sentry/Protocol/Trace.cs
@@ -50,6 +50,21 @@ internal set
     /// <inheritdoc />
     public bool? IsSampled { get; internal set; }
 
+    private Dictionary<string, object?> _data = new();
+
+    /// <summary>
+    /// Get the metadata
+    /// </summary>
+    public IReadOnlyDictionary<string, object?> Data => _data;
+
+    /// <summary>
+    /// Adds metadata to the trace
+    /// </summary>
+    /// <param name="key"></param>
+    /// <param name="value"></param>
+    public void SetData(string key, object? value)
+        => _data[key] = value;
+
     /// <summary>
     /// Clones this instance.
     /// </summary>
@@ -63,7 +78,8 @@ internal set
         Operation = Operation,
         Origin = Origin,
         Status = Status,
-        IsSampled = IsSampled
+        IsSampled = IsSampled,
+        _data = _data.ToDict()
     };
 
     /// <summary>
@@ -103,6 +119,7 @@ public void WriteTo(Utf8JsonWriter writer, IDiagnosticLogger? logger)
         writer.WriteString("origin", Origin ?? Internal.OriginHelper.Manual);
         writer.WriteStringIfNotWhiteSpace("description", Description);
         writer.WriteStringIfNotWhiteSpace("status", Status?.ToString().ToSnakeCase());
+        writer.WriteDictionaryIfNotEmpty("data", _data, logger);
 
         writer.WriteEndObject();
     }
@@ -120,6 +137,7 @@ public static Trace FromJson(JsonElement json)
         var description = json.GetPropertyOrNull("description")?.GetString();
         var status = json.GetPropertyOrNull("status")?.GetString()?.Replace("_", "").ParseEnum<SpanStatus>();
         var isSampled = json.GetPropertyOrNull("sampled")?.GetBoolean();
+        var data = json.GetPropertyOrNull("data")?.GetDictionaryOrNull() ?? new();
 
         return new Trace
         {
@@ -130,7 +148,8 @@ public static Trace FromJson(JsonElement json)
             Origin = origin,
             Description = description,
             Status = status,
-            IsSampled = isSampled
+            IsSampled = isSampled,
+            _data = data
         };
     }
 }
diff --git a/src/Sentry/SentrySpan.cs b/src/Sentry/SentrySpan.cs
index 9031556c7d..e94ca99074 100644
--- a/src/Sentry/SentrySpan.cs
+++ b/src/Sentry/SentrySpan.cs
@@ -66,15 +66,26 @@ public void UnsetTag(string key) =>
         (_tags ??= new Dictionary<string, string>()).Remove(key);
 
     // Aka 'data'
-    private Dictionary<string, object?>? _extra;
     private readonly MetricsSummary? _metricsSummary;
 
+
+    private Dictionary<string, object?>? _data;
+
+    /// <inheritdoc />
+    public IReadOnlyDictionary<string, object?> Data =>
+        _data ??= new Dictionary<string, object?>();
+
+    /// <inheritdoc />
+    public void SetData(string key, object? value) =>
+        (_data ??= new Dictionary<string, object?>())[key] = value;
+
     /// <inheritdoc />
-    public IReadOnlyDictionary<string, object?> Extra => _extra ??= new Dictionary<string, object?>();
+    [Obsolete("Use SetData")]
+    public IReadOnlyDictionary<string, object?> Extra => Data;
 
     /// <inheritdoc />
-    public void SetExtra(string key, object? value) =>
-        (_extra ??= new Dictionary<string, object?>())[key] = value;
+    [Obsolete("Use Data")]
+    public void SetExtra(string key, object? value) => SetData(key, value);
 
     /// <summary>
     /// Initializes an instance of <see cref="SentrySpan"/>.
@@ -100,7 +111,7 @@ public SentrySpan(ISpan tracer)
         Description = tracer.Description;
         Status = tracer.Status;
         IsSampled = tracer.IsSampled;
-        _extra = tracer.Extra.ToDict();
+        _data = tracer.Data.ToDict();
 
         if (tracer is SpanTracer spanTracer)
         {
@@ -138,7 +149,7 @@ public void WriteTo(Utf8JsonWriter writer, IDiagnosticLogger? logger)
         writer.WriteString("start_timestamp", StartTimestamp);
         writer.WriteStringIfNotNull("timestamp", EndTimestamp);
         writer.WriteStringDictionaryIfNotEmpty("tags", _tags!);
-        writer.WriteDictionaryIfNotEmpty("data", _extra!, logger);
+        writer.WriteDictionaryIfNotEmpty("data", _data!, logger);
         writer.WriteDictionaryIfNotEmpty("measurements", _measurements, logger);
         writer.WriteSerializableIfNotNull("_metrics_summary", _metricsSummary, logger);
 
@@ -173,7 +184,7 @@ public static SentrySpan FromJson(JsonElement json)
             Status = status,
             IsSampled = isSampled,
             _tags = tags!,
-            _extra = data!,
+            _data = data!,
             _measurements = measurements,
         };
     }
diff --git a/src/Sentry/SentryTransaction.cs b/src/Sentry/SentryTransaction.cs
index b69acd3f52..386891ec01 100644
--- a/src/Sentry/SentryTransaction.cs
+++ b/src/Sentry/SentryTransaction.cs
@@ -179,12 +179,6 @@ public IReadOnlyList<string> Fingerprint
     /// <inheritdoc />
     public IReadOnlyCollection<Breadcrumb> Breadcrumbs => _breadcrumbs;
 
-    // Not readonly because of deserialization
-    private Dictionary<string, object?> _extra = new();
-
-    /// <inheritdoc />
-    public IReadOnlyDictionary<string, object?> Extra => _extra;
-
     // Not readonly because of deserialization
     private Dictionary<string, string> _tags = new();
 
@@ -270,7 +264,6 @@ public SentryTransaction(ITransactionTracer tracer)
         Sdk = tracer.Sdk;
         Fingerprint = tracer.Fingerprint;
         _breadcrumbs = tracer.Breadcrumbs.ToList();
-        _extra = tracer.Extra.ToDict();
         _tags = tracer.Tags.ToDict();
 
         _spans = FromTracerSpans(tracer);
@@ -339,8 +332,20 @@ public void AddBreadcrumb(Breadcrumb breadcrumb) =>
         _breadcrumbs.Add(breadcrumb);
 
     /// <inheritdoc />
+    public IReadOnlyDictionary<string, object?> Data => _contexts.Trace.Data;
+
+    /// <inheritdoc />
+    [Obsolete("Use Data")]
+    public IReadOnlyDictionary<string, object?> Extra => _contexts.Trace.Data;
+
+    /// <inheritdoc />
+    [Obsolete("Use SetData")]
     public void SetExtra(string key, object? value) =>
-        _extra[key] = value;
+        SetData(key, value);
+
+    /// <inheritdoc />
+    public void SetData(string key, object? value) =>
+        _contexts.Trace.SetData(key, value);
 
     /// <inheritdoc />
     public void SetTag(string key, string value) =>
@@ -401,7 +406,6 @@ public void WriteTo(Utf8JsonWriter writer, IDiagnosticLogger? logger)
         writer.WriteSerializable("sdk", Sdk, logger);
         writer.WriteStringArrayIfNotEmpty("fingerprint", _fingerprint);
         writer.WriteArrayIfNotEmpty("breadcrumbs", _breadcrumbs, logger);
-        writer.WriteDictionaryIfNotEmpty("extra", _extra, logger);
         writer.WriteStringDictionaryIfNotEmpty("tags", _tags!);
         writer.WriteArrayIfNotEmpty("spans", _spans, logger);
         writer.WriteDictionaryIfNotEmpty("measurements", _measurements, logger);
@@ -459,7 +463,6 @@ public static SentryTransaction FromJson(JsonElement json)
             Sdk = sdk,
             _fingerprint = fingerprint,
             _breadcrumbs = breadcrumbs,
-            _extra = extra,
             _tags = tags,
             _measurements = measurements,
             _spans = spans
diff --git a/src/Sentry/SpanTracer.cs b/src/Sentry/SpanTracer.cs
index 9dbbbc4b96..ed51d48eaa 100644
--- a/src/Sentry/SpanTracer.cs
+++ b/src/Sentry/SpanTracer.cs
@@ -85,10 +85,17 @@ public void UnsetTag(string key) =>
     private readonly ConcurrentDictionary<string, object?> _data = new();
 
     /// <inheritdoc />
-    public IReadOnlyDictionary<string, object?> Extra => _data;
+    public IReadOnlyDictionary<string, object?> Data => _data;
 
     /// <inheritdoc />
-    public void SetExtra(string key, object? value) => _data[key] = value;
+    public void SetData(string key, object? value) =>
+        _data[key] = value;
+
+    /// <inheritdoc />
+    public IReadOnlyDictionary<string, object?> Extra => Data;
+
+    /// <inheritdoc />
+    public void SetExtra(string key, object? value) => SetData(key, value);
 
     internal Func<bool>? IsFiltered { get; set; }
 
diff --git a/src/Sentry/TransactionTracer.cs b/src/Sentry/TransactionTracer.cs
index 69376ad71f..e8059a2d00 100644
--- a/src/Sentry/TransactionTracer.cs
+++ b/src/Sentry/TransactionTracer.cs
@@ -157,10 +157,15 @@ public IReadOnlyList<string> Fingerprint
     /// <inheritdoc />
     public IReadOnlyCollection<Breadcrumb> Breadcrumbs => _breadcrumbs;
 
-    private readonly ConcurrentDictionary<string, object?> _extra = new();
+    private readonly ConcurrentDictionary<string, object?> _data = new();
 
     /// <inheritdoc />
-    public IReadOnlyDictionary<string, object?> Extra => _extra;
+    [Obsolete("Use Data")]
+    public IReadOnlyDictionary<string, object?> Extra => _data;
+
+    /// <inheritdoc />
+    public IReadOnlyDictionary<string, object?> Data => _data;
+
 
     private readonly ConcurrentDictionary<string, string> _tags = new();
 
@@ -270,7 +275,11 @@ internal TransactionTracer(IHub hub, ITransactionContext context, TimeSpan? idle
     public void AddBreadcrumb(Breadcrumb breadcrumb) => _breadcrumbs.Add(breadcrumb);
 
     /// <inheritdoc />
-    public void SetExtra(string key, object? value) => _extra[key] = value;
+    [Obsolete("Use SetData")]
+    public void SetExtra(string key, object? value) => _data[key] = value;
+
+    /// <inheritdoc />
+    public void SetData(string key, object? value) => _data[key] = value;
 
     /// <inheritdoc />
     public void SetTag(string key, string value) => _tags[key] = value;
diff --git a/test/Sentry.Tests/Protocol/SentryTransactionTests.cs b/test/Sentry.Tests/Protocol/SentryTransactionTests.cs
index 597e275c15..4e0872ada1 100644
--- a/test/Sentry.Tests/Protocol/SentryTransactionTests.cs
+++ b/test/Sentry.Tests/Protocol/SentryTransactionTests.cs
@@ -207,7 +207,7 @@ public void SerializeObject_AllPropertiesSetToNonDefault_SerializesValidObject()
             "category",
             BreadcrumbLevel.Warning));
 
-        transaction.SetExtra("extra_key", "extra_value");
+        transaction.SetData("extra_key", "extra_value");
         transaction.Fingerprint = new[] { "fingerprint" };
         transaction.SetTag("tag_key", "tag_value");
         transaction.SetMeasurement("measurement_1", 111);
diff --git a/test/Sentry.Tests/SerializationTests.cs b/test/Sentry.Tests/SerializationTests.cs
new file mode 100644
index 0000000000..51a57bdd34
--- /dev/null
+++ b/test/Sentry.Tests/SerializationTests.cs
@@ -0,0 +1,50 @@
+using System.Text.Json.Nodes;
+
+namespace Sentry.Tests;
+
+public partial class SerializationTests
+{
+    private readonly IDiagnosticLogger _testOutputLogger;
+
+    public SerializationTests(ITestOutputHelper output)
+    {
+        _testOutputLogger = new TestOutputDiagnosticLogger(output);
+    }
+
+    [Fact]
+    public void Serialization_TransactionAndSpanData()
+    {
+        var hub = Substitute.For<IHub>();
+        var context = new TransactionContext("name", "operation", new SentryTraceHeader(SentryId.Empty, SpanId.Empty, false));
+        var transactionTracer = new TransactionTracer(hub, context);
+        var span = transactionTracer.StartChild("childop");
+        span.SetData("span1", "value1");
+
+        var transaction = new SentryTransaction(transactionTracer)
+        {
+            IsSampled = false
+        };
+        transaction.SetData("transaction1", "transaction_value");
+        var json = transaction.ToJsonString(_testOutputLogger);
+        _testOutputLogger.LogDebug(json);
+
+        var node = JsonNode.Parse(json);
+        var dataNode = node?["contexts"]?["trace"]?["data"]?["transaction1"]?.GetValue<string>();
+        dataNode.Should().NotBeNull("contexts.trace.data.transaction1 not found");
+        dataNode.Should().Be("transaction_value");
+
+        var spansNode = node?["spans"]?.AsArray();
+        spansNode.Should().NotBeNull("spans not found");
+        var spanDataNode = spansNode!.FirstOrDefault()?["data"]?["span1"]?.GetValue<string>();
+        spanDataNode.Should().NotBeNull("spans.data not found");
+        spanDataNode.Should().Be("value1");
+
+        // verify deserialization
+        var reader = new Utf8JsonReader(Encoding.UTF8.GetBytes(json));
+        var el = JsonElement.ParseValue(ref reader);
+        var backTransaction = SentryTransaction.FromJson(el);
+
+        backTransaction.Spans.First().Data["span1"].Should().Be("value1", "Span value missing");
+        backTransaction.Contexts.Trace.Data["transaction1"].Should().Be("transaction_value", "Transaction value missing");
+    }
+}
diff --git a/test/Sentry.Tests/SerializationTests.verify.cs b/test/Sentry.Tests/SerializationTests.verify.cs
index 86a671cb3c..65b08857fa 100644
--- a/test/Sentry.Tests/SerializationTests.verify.cs
+++ b/test/Sentry.Tests/SerializationTests.verify.cs
@@ -4,15 +4,8 @@
 
 namespace Sentry.Tests;
 
-public class SerializationTests
+public partial class SerializationTests
 {
-    private readonly IDiagnosticLogger _testOutputLogger;
-
-    public SerializationTests(ITestOutputHelper output)
-    {
-        _testOutputLogger = new TestOutputDiagnosticLogger(output);
-    }
-
     [Theory]
     [MemberData(nameof(GetData))]
     public async Task Serialization(string name, object target)