diff --git a/CLAUDE.md b/CLAUDE.md
index cd6b7d4..e515f07 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -55,13 +55,15 @@ Internal methods `IsAlreadyRunning()` and `WritePidFile()` are exposed to tests
 
 JSON-serialized `ProcessInfo` with fields: `ProcessId`, `ProcessName`, `StartTime`, `MainModuleFileName`. Includes backward compatibility for legacy files that stored only a plain integer PID.
 
+Serialization goes through the source-generated `ProcessInfoJsonContext`, never the reflection overloads: apps published trimmed or Native AOT run with reflection-based System.Text.Json disabled. The library sets `IsAotCompatible` on net7.0+, so a reflection call is a build error (IL2026/IL3050). The test project sets `JsonSerializerIsReflectionEnabledByDefault=false` and reads the PID file through its own `TestJsonContext`, so every test runs the way those apps do.
+
 ### Multi-targeting
 
 The library targets multiple frameworks via `ktsu.Sdk`. Uses `#if NET5_0_OR_GREATER` preprocessor directives (e.g., `Environment.ProcessId` vs `Process.GetCurrentProcess().Id`).
 
 ## Testing
 
-Tests use MSTest (`MSTest.Sdk`) targeting net10.0 only. Tests are marked `[DoNotParallelize]` because they share the PID file on disk. Each test cleans up the PID file in `[TestInitialize]`. The test project mirrors the internal `ProcessInfo` class as a private nested class for deserialization.
+Tests use MSTest (`MSTest.Sdk`) targeting net10.0 only. Tests are marked `[DoNotParallelize]` because they share the PID file on disk. Each test cleans up the PID file in `[TestInitialize]`. The test project mirrors the internal `ProcessInfo` class as a nested class, serialized through `TestJsonContext`.
 
 ## CI/CD
 
diff --git a/SingleAppInstance.Test/SingleAppInstance.Test.csproj b/SingleAppInstance.Test/SingleAppInstance.Test.csproj
index 0537f1d..e46a422 100644
--- a/SingleAppInstance.Test/SingleAppInstance.Test.csproj
+++ b/SingleAppInstance.Test/SingleAppInstance.Test.csproj
@@ -6,6 +6,9 @@
     <IsTestProject>true</IsTestProject>
     <TargetFramework>net10.0</TargetFramework>
     <TargetFrameworks></TargetFrameworks>
+    <!-- A trimmed or Native AOT app runs with reflection-based System.Text.Json disabled, so the
+         tests do too: a reflection call in the library fails every test that writes a PID file. -->
+    <JsonSerializerIsReflectionEnabledByDefault>false</JsonSerializerIsReflectionEnabledByDefault>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/SingleAppInstance.Test/SingleAppInstanceTests.cs b/SingleAppInstance.Test/SingleAppInstanceTests.cs
index ea5909f..0c3a934 100644
--- a/SingleAppInstance.Test/SingleAppInstanceTests.cs
+++ b/SingleAppInstance.Test/SingleAppInstanceTests.cs
@@ -42,7 +42,7 @@ public void WritePidFile_ShouldCreateFileWithCurrentProcessInfo()
 
 		// Verify file content
 		string fileContent = File.ReadAllText(pidFilePath);
-		ProcessInfo? processInfo = JsonSerializer.Deserialize<ProcessInfo>(fileContent);
+		ProcessInfo? processInfo = JsonSerializer.Deserialize(fileContent, TestJsonContext.Default.ProcessInfo);
 
 		Assert.IsNotNull(processInfo);
 		using Process currentProcess = Process.GetCurrentProcess();
@@ -79,7 +79,7 @@ public void WritePidFile_ShouldOverwriteExistingFile()
 		// Assert
 		string content = File.ReadAllText(pidFilePath);
 		Assert.AreNotEqual("old content", content);
-		ProcessInfo? processInfo = JsonSerializer.Deserialize<ProcessInfo>(content);
+		ProcessInfo? processInfo = JsonSerializer.Deserialize(content, TestJsonContext.Default.ProcessInfo);
 		Assert.IsNotNull(processInfo);
 		Assert.AreEqual(Environment.ProcessId, processInfo.ProcessId);
 	}
@@ -109,7 +109,7 @@ public void IsAlreadyRunning_WithCurrentProcessId_ShouldReturnFalse()
 			MainModuleFileName = currentProcess.MainModule?.FileName,
 		};
 
-		string json = JsonSerializer.Serialize(processInfo);
+		string json = JsonSerializer.Serialize(processInfo, TestJsonContext.Default.ProcessInfo);
 		File.WriteAllText(pidFilePath, json);
 
 		// Act
@@ -198,7 +198,7 @@ public void IsAlreadyRunning_WithNonExistentPid_ShouldReturnFalse()
 			MainModuleFileName = "NonExistentFile.exe",
 		};
 
-		string json = JsonSerializer.Serialize(processInfo);
+		string json = JsonSerializer.Serialize(processInfo, TestJsonContext.Default.ProcessInfo);
 		File.WriteAllText(pidFilePath, json);
 
 		// Act
@@ -283,7 +283,7 @@ public void IsAlreadyRunning_WithRunningProcessButDifferentName_ShouldReturnFals
 				MainModuleFileName = "C:\\nonexistent\\fake.exe",
 			};
 
-			string json = JsonSerializer.Serialize(processInfo);
+			string json = JsonSerializer.Serialize(processInfo, TestJsonContext.Default.ProcessInfo);
 			File.WriteAllText(pidFilePath, json);
 
 			// Act
@@ -309,7 +309,7 @@ public void IsAlreadyRunning_WithMatchingProcessButDifferentStartTime_ShouldRetu
 
 		ProcessInfo processInfo = DescribeProcess(helper.Process);
 		processInfo.StartTime = processInfo.StartTime.AddHours(-1);
-		File.WriteAllText(pidFilePath, JsonSerializer.Serialize(processInfo));
+		File.WriteAllText(pidFilePath, JsonSerializer.Serialize(processInfo, TestJsonContext.Default.ProcessInfo));
 
 		// Act
 		bool result = SingleAppInstance.IsAlreadyRunning();
@@ -325,7 +325,7 @@ public void IsAlreadyRunning_WithMatchingProcessAndStartTime_ShouldReturnTrue()
 		string pidFilePath = SingleAppInstance.PidFilePath;
 		using HelperProcess helper = HelperProcess.Start("StartTimeHelper");
 
-		File.WriteAllText(pidFilePath, JsonSerializer.Serialize(DescribeProcess(helper.Process)));
+		File.WriteAllText(pidFilePath, JsonSerializer.Serialize(DescribeProcess(helper.Process), TestJsonContext.Default.ProcessInfo));
 
 		// Act
 		bool result = SingleAppInstance.IsAlreadyRunning();
@@ -343,7 +343,7 @@ public void IsAlreadyRunning_WithMatchingProcessAndNoStoredStartTime_ShouldRetur
 
 		ProcessInfo processInfo = DescribeProcess(helper.Process);
 		processInfo.StartTime = default;
-		File.WriteAllText(pidFilePath, JsonSerializer.Serialize(processInfo));
+		File.WriteAllText(pidFilePath, JsonSerializer.Serialize(processInfo, TestJsonContext.Default.ProcessInfo));
 
 		// Act
 		bool result = SingleAppInstance.IsAlreadyRunning();
@@ -406,7 +406,7 @@ public void IsAlreadyRunning_WithHighNonExistentPid_ShouldReturnFalse()
 			MainModuleFileName = "fake.exe",
 		};
 
-		string json = JsonSerializer.Serialize(processInfo);
+		string json = JsonSerializer.Serialize(processInfo, TestJsonContext.Default.ProcessInfo);
 		File.WriteAllText(pidFilePath, json);
 
 		// Act
@@ -443,7 +443,7 @@ public void IsAlreadyRunning_WithZeroPid_ShouldReturnFalse()
 			MainModuleFileName = "fake.exe",
 		};
 
-		string json = JsonSerializer.Serialize(processInfo);
+		string json = JsonSerializer.Serialize(processInfo, TestJsonContext.Default.ProcessInfo);
 		File.WriteAllText(pidFilePath, json);
 
 		// Act
@@ -469,7 +469,7 @@ public void ShouldLaunch_WithNoExistingInstance_ShouldReturnTrue()
 
 		// Verify the PID file content matches the current process
 		string fileContent = File.ReadAllText(pidFilePath);
-		ProcessInfo? processInfo = JsonSerializer.Deserialize<ProcessInfo>(fileContent);
+		ProcessInfo? processInfo = JsonSerializer.Deserialize(fileContent, TestJsonContext.Default.ProcessInfo);
 		Assert.IsNotNull(processInfo);
 		Assert.AreEqual(Environment.ProcessId, processInfo.ProcessId);
 	}
@@ -499,7 +499,7 @@ public void IsAlreadyRunning_WithGarbageSuffixedPidFileForRunningInstance_Should
 		string pidFilePath = SingleAppInstance.PidFilePath;
 		using HelperProcess helper = HelperProcess.Start("TornPidHelper");
 
-		File.WriteAllText(pidFilePath, JsonSerializer.Serialize(DescribeProcess(helper.Process)) + "0\"}");
+		File.WriteAllText(pidFilePath, JsonSerializer.Serialize(DescribeProcess(helper.Process), TestJsonContext.Default.ProcessInfo) + "0\"}");
 
 		// Act
 		bool result = SingleAppInstance.IsAlreadyRunning();
@@ -515,7 +515,7 @@ public void ShouldLaunch_WithGarbageSuffixedPidFileForRunningInstance_ShouldRetu
 		string pidFilePath = SingleAppInstance.PidFilePath;
 		using HelperProcess helper = HelperProcess.Start("TornPidHelper");
 
-		File.WriteAllText(pidFilePath, JsonSerializer.Serialize(DescribeProcess(helper.Process)) + "0\"}");
+		File.WriteAllText(pidFilePath, JsonSerializer.Serialize(DescribeProcess(helper.Process), TestJsonContext.Default.ProcessInfo) + "0\"}");
 
 		// Act
 		bool result = SingleAppInstance.ShouldLaunch();
@@ -634,7 +634,7 @@ public void WritePidFile_WhileBeingRead_ReaderNeverSeesAPartialFile()
 
 				try
 				{
-					if (JsonSerializer.Deserialize<ProcessInfo>(content) is null)
+					if (JsonSerializer.Deserialize(content, TestJsonContext.Default.ProcessInfo) is null)
 					{
 						partialReads++;
 						lastPartialContent = content;
@@ -715,7 +715,7 @@ public void TryWritePidFile_WhenPidFileCanBeWritten_ShouldReturnTrue()
 
 		// Assert
 		Assert.IsTrue(result);
-		ProcessInfo? processInfo = JsonSerializer.Deserialize<ProcessInfo>(File.ReadAllText(SingleAppInstance.PidFilePath));
+		ProcessInfo? processInfo = JsonSerializer.Deserialize(File.ReadAllText(SingleAppInstance.PidFilePath), TestJsonContext.Default.ProcessInfo);
 		Assert.IsNotNull(processInfo);
 		Assert.AreEqual(Environment.ProcessId, processInfo.ProcessId);
 	}
@@ -767,7 +767,7 @@ public void WritePidFile_ContentShouldBeValidJson()
 		ProcessInfo? deserialized = null;
 		try
 		{
-			deserialized = JsonSerializer.Deserialize<ProcessInfo>(content);
+			deserialized = JsonSerializer.Deserialize(content, TestJsonContext.Default.ProcessInfo);
 		}
 		catch (JsonException)
 		{
@@ -789,7 +789,7 @@ public void WritePidFile_CalledTwice_ShouldSucceed()
 		// Assert
 		Assert.IsTrue(File.Exists(SingleAppInstance.PidFilePath));
 		string content = File.ReadAllText(SingleAppInstance.PidFilePath);
-		ProcessInfo? processInfo = JsonSerializer.Deserialize<ProcessInfo>(content);
+		ProcessInfo? processInfo = JsonSerializer.Deserialize(content, TestJsonContext.Default.ProcessInfo);
 		Assert.IsNotNull(processInfo);
 		Assert.AreEqual(Environment.ProcessId, processInfo.ProcessId);
 	}
@@ -1013,8 +1013,10 @@ public void Dispose()
 		}
 	}
 
-	// This class needs to mirror the internal ProcessInfo class for testing
-	private sealed class ProcessInfo
+	// This class needs to mirror the internal ProcessInfo class for testing. It is read and written
+	// through TestJsonContext because the test project, like a trimmed or Native AOT app, runs with
+	// reflection-based serialization disabled.
+	internal sealed class ProcessInfo
 	{
 		public int ProcessId { get; set; }
 		public string? ProcessName { get; set; }
diff --git a/SingleAppInstance.Test/TestJsonContext.cs b/SingleAppInstance.Test/TestJsonContext.cs
new file mode 100644
index 0000000..3249952
--- /dev/null
+++ b/SingleAppInstance.Test/TestJsonContext.cs
@@ -0,0 +1,15 @@
+// Copyright (c) 2023-2026 ktsu-dev contributors
+
+namespace ktsu.SingleAppInstance.Test;
+
+using System.Text.Json.Serialization;
+
+/// <summary>
+/// Source-generated serialization for the test's mirror of the PID file record.
+/// </summary>
+/// <remarks>
+/// The test project disables reflection-based serialization, as a trimmed or Native AOT app does,
+/// so that every test exercises the library the way those apps run it.
+/// </remarks>
+[JsonSerializable(typeof(SingleAppInstanceTests.ProcessInfo))]
+internal sealed partial class TestJsonContext : JsonSerializerContext;
diff --git a/SingleAppInstance/ProcessInfoJsonContext.cs b/SingleAppInstance/ProcessInfoJsonContext.cs
new file mode 100644
index 0000000..7453144
--- /dev/null
+++ b/SingleAppInstance/ProcessInfoJsonContext.cs
@@ -0,0 +1,16 @@
+// Copyright (c) 2023-2026 ktsu-dev contributors
+
+namespace ktsu.SingleAppInstance;
+
+using System.Text.Json.Serialization;
+
+/// <summary>
+/// Source-generated serialization for the PID file record.
+/// </summary>
+/// <remarks>
+/// An app published trimmed or as Native AOT runs with reflection-based System.Text.Json disabled,
+/// so the reflection overloads would throw on its first launch. The JSON shape is the same as the
+/// reflection serializer's, so PID files written by earlier versions still read.
+/// </remarks>
+[JsonSerializable(typeof(SingleAppInstance.ProcessInfo))]
+internal sealed partial class ProcessInfoJsonContext : JsonSerializerContext;
diff --git a/SingleAppInstance/SingleAppInstance.cs b/SingleAppInstance/SingleAppInstance.cs
index 2dda7d4..827bc7a 100644
--- a/SingleAppInstance/SingleAppInstance.cs
+++ b/SingleAppInstance/SingleAppInstance.cs
@@ -214,7 +214,7 @@ private static PidFileState CheckPidFileContents(string pidFileContents, int cur
 		try
 		{
 			Utf8JsonReader reader = new(Encoding.UTF8.GetBytes(pidFileContents));
-			storedProcess = JsonSerializer.Deserialize<ProcessInfo>(ref reader);
+			storedProcess = JsonSerializer.Deserialize(ref reader, ProcessInfoJsonContext.Default.ProcessInfo);
 			if (storedProcess == null)
 			{
 				return PidFileState.NoInstance;
@@ -469,7 +469,7 @@ internal static void WritePidFile()
 			MainModuleFileName = currentProcess.MainModule?.FileName
 		};
 
-		string json = JsonSerializer.Serialize(processInfo);
+		string json = JsonSerializer.Serialize(processInfo, ProcessInfoJsonContext.Default.ProcessInfo);
 		string pidFilePath = PidFilePath;
 		string temporaryPath = $"{pidFilePath}.{Guid.NewGuid():N}.tmp";
 
diff --git a/SingleAppInstance/SingleAppInstance.csproj b/SingleAppInstance/SingleAppInstance.csproj
index 16f3437..0c17599 100644
--- a/SingleAppInstance/SingleAppInstance.csproj
+++ b/SingleAppInstance/SingleAppInstance.csproj
@@ -2,6 +2,12 @@
   <Sdk Name="Microsoft.NET.Sdk" />
   <Sdk Name="ktsu.Sdk" />
 
+  <!-- Trim and AOT analysis, so a reflection-based call that would crash a trimmed or Native AOT
+       app is a build error here rather than a crash there. -->
+  <PropertyGroup Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net7.0'))">
+    <IsAotCompatible>true</IsAotCompatible>
+  </PropertyGroup>
+
   <ItemGroup>
     <PackageReference Include="ktsu.AppDataStorage" />
     <PackageReference Include="ktsu.Semantics.Paths" />