diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6abddf2c2..6a9698763 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -431,6 +431,23 @@ jobs:
     with:
       unity-version: ${{ matrix.unity-version }}
 
+  test-build-windows-x86:
+    # Unity still ships a 32-bit standalone player and it needs its own sentry-native build.
+    # One version, native backend only: x86 is on its way out and the x64 matrix already covers
+    # the version spread and the crashpad backend. The version is the first matrix entry rather
+    # than a literal, because `test-create` only builds what the matrix holds and Unity-bump PRs
+    # narrow it to the bumped version. The lists in create-unity-matrix.yml are oldest-first.
+    name: Build Windows x86 ${{ fromJSON(needs.create-unity-matrix.outputs.unity-matrix).unity-version[0] }} Integration Test
+    if: ${{ !startsWith(github.ref, 'refs/heads/release/') }}
+    needs: [test-create, create-unity-matrix]
+    secrets:
+      UNITY_LICENSE_SERVER_CONFIG: ${{ secrets.UNITY_LICENSE_SERVER_CONFIG }}
+      SENTRY_AUTH_TOKEN: ${{ secrets.SENTRY_AUTH_TOKEN }}
+      SENTRY_TEST_DSN: ${{ secrets.SENTRY_TEST_DSN }}
+    uses: ./.github/workflows/test-build-windows-x86.yml
+    with:
+      unity-version: ${{ fromJSON(needs.create-unity-matrix.outputs.unity-matrix).unity-version[0] }}
+
   test-build-windows-mono:
     # The Mono scripting backend resolves P/Invokes differently than IL2CPP, so it needs its own
     # player. One version, default (Crashpad) backend only: the IL2CPP matrix already covers the
@@ -500,6 +517,20 @@ jobs:
       platform: windows
       backend: ${{ matrix.backend }}
 
+  test-run-windows-x86:
+    name: Run Windows x86 native ${{ fromJSON(needs.create-unity-matrix.outputs.unity-matrix).unity-version[0] }} Integration Test
+    if: ${{ !startsWith(github.ref, 'refs/heads/release/') }}
+    needs: [test-build-windows-x86, create-unity-matrix]
+    secrets:
+      SENTRY_AUTH_TOKEN: ${{ secrets.SENTRY_AUTH_TOKEN }}
+      SENTRY_TEST_DSN: ${{ secrets.SENTRY_TEST_DSN }}
+    uses: ./.github/workflows/test-run-desktop.yml
+    with:
+      unity-version: ${{ fromJSON(needs.create-unity-matrix.outputs.unity-matrix).unity-version[0] }}
+      platform: windows
+      architecture: x86
+      backend: native
+
   test-run-windows-mono:
     name: Run Windows Mono ${{ fromJSON(needs.create-unity-matrix.outputs.unity-matrix).unity-version[0] }} Integration Test
     if: ${{ !startsWith(github.ref, 'refs/heads/release/') }}
diff --git a/.github/workflows/test-build-windows-x86.yml b/.github/workflows/test-build-windows-x86.yml
new file mode 100644
index 000000000..fac318d77
--- /dev/null
+++ b/.github/workflows/test-build-windows-x86.yml
@@ -0,0 +1,143 @@
+name: "Test: Build Windows x86"
+on:
+  workflow_call:
+    inputs:
+      unity-version:
+        required: true
+        type: string
+    secrets:
+      UNITY_LICENSE_SERVER_CONFIG:
+        required: true
+      SENTRY_AUTH_TOKEN:
+        required: true
+      SENTRY_TEST_DSN:
+        required: true
+
+defaults:
+  run:
+    shell: pwsh
+
+jobs:
+  build:
+    name: Windows x86 ${{ inputs.unity-version }}
+    runs-on: windows-latest
+    env:
+      UNITY_VERSION: ${{ inputs.unity-version }}
+      BUILD_PLATFORM: Windows-x86
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Load env
+        id: env
+        run: |
+          $u = (Get-Content scripts/unity-versions.json -Raw | ConvertFrom-Json).'${{ env.UNITY_VERSION }}'
+          "unityVersion=$($u.version)"     >> $env:GITHUB_OUTPUT
+          "unityChangeset=$($u.changeset)" >> $env:GITHUB_OUTPUT
+
+      - name: Setup Unity
+        uses: getsentry/setup-unity@61c0c0944851685b6c1225e940d1b1ab349e3aa3
+        with:
+          unity-version: ${{ steps.env.outputs.unityVersion }}
+          unity-version-changeset: ${{ steps.env.outputs.unityChangeset }}
+          unity-modules: windows-il2cpp
+
+      - name: Create Unity license config
+        run: |
+          New-Item -Path "C:/ProgramData/Unity/config/" -ItemType Directory -Force
+          Set-Content -Path "C:/ProgramData/Unity/config/services-config.json" -Value "$env:UNITY_LICENSE_SERVER_CONFIG"
+        env:
+          UNITY_LICENSE_SERVER_CONFIG: ${{ secrets.UNITY_LICENSE_SERVER_CONFIG }}
+
+      - name: Download IntegrationTest project
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
+        with:
+          name: test-${{ env.UNITY_VERSION }}
+
+      - name: Extract project archive
+        run: tar -xvzf test-project.tar.gz
+
+      - name: Restore Unity Library cache
+        uses: actions/cache/restore@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
+        with:
+          path: samples/IntegrationTest/Library
+          key: it-library-windows-x86-${{ env.UNITY_VERSION }}-${{ github.run_id }}
+          restore-keys: |
+            it-library-windows-x86-${{ env.UNITY_VERSION }}-
+
+      - name: Download UPM package
+        uses: ./.github/actions/wait-for-artifact
+        with:
+          name: package-release
+
+      - name: Extract UPM package
+        run: ./test/Scripts.Integration.Test/extract-package.ps1
+
+      - name: Add Sentry to the project
+        run: ./test/Scripts.Integration.Test/add-sentry.ps1 -UnityPath "$env:UNITY_PATH" -PackagePath "test-package-release"
+
+      - name: Download DependencyConflict package
+        uses: ./.github/actions/wait-for-artifact
+        with:
+          name: dependency-conflict-package
+          path: dependency-conflict-package
+
+      - name: Add DependencyConflict to the project
+        run: ./test/Scripts.Integration.Test/add-dependency-conflict.ps1 -PackagePath "dependency-conflict-package"
+
+      - name: Configure Sentry
+        run: ./test/Scripts.Integration.Test/configure-sentry.ps1 -UnityPath "$env:UNITY_PATH" -Platform Windows
+        env:
+          SENTRY_DSN: ${{ secrets.SENTRY_TEST_DSN }}
+
+      # Native backend only. The point of this job is that a 32-bit player loads a 32-bit
+      # sentry-native at all; covering both backends here would double Unity licence usage
+      # for no extra signal. The x64 matrix still covers crashpad.
+      - name: Select the Native backend
+        run: |
+          $optionsPath = "samples/IntegrationTest/Assets/Scripts/IntegrationOptionsConfiguration.cs"
+          $content = Get-Content $optionsPath -Raw
+          $content = $content -replace 'WindowsBackend = WindowsBackend.Crashpad', 'WindowsBackend = WindowsBackend.Native'
+          Set-Content $optionsPath $content
+
+      - name: Build with Sentry SDK
+        run: ./test/Scripts.Integration.Test/build-project.ps1 -UnityPath "$env:UNITY_PATH" -Platform Windows-x86 -UnityVersion "$env:UNITY_VERSION"
+        env:
+          SENTRY_AUTH_TOKEN: ${{ secrets.SENTRY_AUTH_TOKEN }}
+
+      - name: Assert symbols and sources were uploaded
+        run: ./test/Scripts.Integration.Test/assert-symbol-upload.ps1 -LogPath unity.log
+
+      # We create tar explicitly because upload-artifact is slow for many files.
+      - name: Create archive
+        run: |
+          Remove-Item -Recurse -Force samples/IntegrationTest/Build/*_BackUpThisFolder_ButDontShipItWithYourGame -ErrorAction SilentlyContinue
+          Copy-Item unity.log samples/IntegrationTest/Build/ -ErrorAction SilentlyContinue
+          tar -cvzf test-app-desktop.tar.gz samples/IntegrationTest/Build
+
+      - name: Upload test app
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
+        with:
+          name: testapp-desktop-compiled-${{ env.UNITY_VERSION }}-windows-x86-native
+          if-no-files-found: error
+          path: test-app-desktop.tar.gz
+          retention-days: 14
+
+      - name: Save Unity Library cache
+        if: github.ref == 'refs/heads/main'
+        uses: actions/cache/save@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
+        with:
+          path: samples/IntegrationTest/Library
+          key: it-library-windows-x86-${{ env.UNITY_VERSION }}-${{ github.run_id }}
+
+      - name: Upload IntegrationTest project on failure
+        if: ${{ failure() }}
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
+        with:
+          name: failed-project-desktop-windows-x86-${{ env.UNITY_VERSION }}
+          path: |
+            samples/IntegrationTest
+            unity.log
+            !samples/IntegrationTest/Build/*_BackUpThisFolder_ButDontShipItWithYourGame
+          retention-days: 14
diff --git a/.github/workflows/test-run-desktop.yml b/.github/workflows/test-run-desktop.yml
index 381d52da3..4cf4f7e24 100644
--- a/.github/workflows/test-run-desktop.yml
+++ b/.github/workflows/test-run-desktop.yml
@@ -14,6 +14,11 @@ on:
         type: string
         default: ""
         description: "macOS: native or cocoa. Windows: native or crashpad. Linux: native or breakpad."
+      architecture:
+        required: false
+        type: string
+        default: ""
+        description: "Only set for non-default architectures, e.g. x86 for the 32-bit Windows player."
       scripting:
         required: false
         type: string
@@ -31,7 +36,7 @@ defaults:
 
 jobs:
   run:
-    name: ${{ inputs.platform }}${{ inputs.scripting && format(' {0}', inputs.scripting) || '' }}${{ inputs.backend && format(' ({0})', inputs.backend) || '' }} ${{ inputs.unity-version }}
+    name: ${{ inputs.platform }}${{ inputs.architecture && format(' {0}', inputs.architecture) || '' }}${{ inputs.scripting && format(' {0}', inputs.scripting) || '' }}${{ inputs.backend && format(' ({0})', inputs.backend) || '' }} ${{ inputs.unity-version }}
     runs-on: ${{ inputs.platform == 'linux' && 'ubuntu-latest' || inputs.platform == 'macos' && 'macos-latest' || 'windows-latest' }}
     env:
       SENTRY_DSN: ${{ secrets.SENTRY_TEST_DSN }}
@@ -48,7 +53,7 @@ jobs:
       - name: Download test app artifact
         uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
         with:
-          name: testapp-desktop-compiled-${{ inputs.unity-version }}-${{ inputs.platform }}${{ inputs.scripting && format('-{0}', inputs.scripting) || '' }}${{ inputs.backend && format('-{0}', inputs.backend) || '' }}
+          name: testapp-desktop-compiled-${{ inputs.unity-version }}-${{ inputs.platform }}${{ inputs.architecture && format('-{0}', inputs.architecture) || '' }}${{ inputs.scripting && format('-{0}', inputs.scripting) || '' }}${{ inputs.backend && format('-{0}', inputs.backend) || '' }}
 
       - name: Extract test app
         run: tar -xvzf test-app-desktop.tar.gz
@@ -97,7 +102,7 @@ jobs:
         if: ${{ failure() }}
         uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
-          name: testapp-desktop-logs-${{ inputs.platform }}${{ inputs.scripting && format('-{0}', inputs.scripting) || '' }}${{ inputs.backend && format('-{0}', inputs.backend) || '' }}-${{ inputs.unity-version }}
+          name: testapp-desktop-logs-${{ inputs.platform }}${{ inputs.architecture && format('-{0}', inputs.architecture) || '' }}${{ inputs.scripting && format('-{0}', inputs.scripting) || '' }}${{ inputs.backend && format('-{0}', inputs.backend) || '' }}-${{ inputs.unity-version }}
           path: |
             test/IntegrationTest/results/
           retention-days: 14
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1fc710007..898099694 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Fixes
+
+- Native crash capture now works on 32-bit Windows standalone builds. The SDK shipped only an x64 library while enabling native support for both architectures, so the player failed to load it. The P/Invokes into `sentry-native` also declare `Cdecl` now - without it the 32-bit player corrupted its stack on the first call. ([#2847](https://github.com/getsentry/sentry-unity/pull/2847))
+
 ### Dependencies
 
 - Bump Native SDK from v0.16.6 to v0.17.0 ([#2862](https://github.com/getsentry/sentry-unity/pull/2862))
diff --git a/build/native-sdks.targets b/build/native-sdks.targets
index ca6b954aa..c095e81b3 100644
--- a/build/native-sdks.targets
+++ b/build/native-sdks.targets
@@ -124,83 +124,94 @@
   <!--
     Build the Sentry Native SDK for Windows:
         dotnet msbuild /t:BuildWindowsSDK src/Sentry.Unity
-    Always wipes prior outputs and rebuilds.
+    Always wipes prior outputs and rebuilds. Both architectures are built; Unity still ships a
+    32-bit standalone player and it cannot load the x64 library. Artifacts land in an `x86/` or
+    `x64/` subfolder and the post-build step picks one based on the build target.
   -->
   <Target Name="BuildWindowsSDK" Condition="'$(MSBuildProjectName)' == 'Sentry.Unity'">
     <Error Condition="!$([MSBuild]::IsOSPlatform('Windows'))" Text="BuildWindowsSDK can only run on Windows." />
     <Error Condition="!Exists('$(SentryNativeRoot)')" Text="sentry-native submodule not checked out at $(SentryNativeRoot). Run: git submodule update --init modules/sentry-native" />
 
-    <Message Importance="High" Text="Building Sentry Native SDK for Windows (clean rebuild)." />
+    <RemoveDir Directories="$(SentryWindowsArtifactsDestination)" ContinueOnError="true" />
 
-    <!-- Wipe prior outputs -->
-    <RemoveDir Directories="$(SentryNativeRoot)build" ContinueOnError="true" />
-    <Delete Files="$(SentryWindowsArtifactsDestination)crashpad_handler.exe" ContinueOnError="true" />
-    <Delete Files="$(SentryWindowsArtifactsDestination)crashpad_wer.dll" ContinueOnError="true" />
-    <Delete Files="$(SentryWindowsArtifactsDestination)crashpad_wer.pdb" ContinueOnError="true" />
-    <Delete Files="$(SentryWindowsArtifactsDestination)sentry.dll" ContinueOnError="true" />
-    <Delete Files="$(SentryWindowsArtifactsDestination)$(SentryWindowsLibraryName)" ContinueOnError="true" />
-    <Delete Files="$(SentryWindowsArtifactsDestination)sentry.pdb" ContinueOnError="true" />
+    <MSBuild Projects="$(MSBuildProjectFullPath)" Targets="_BuildWindowsSDKForArch" Properties="SentryWindowsArch=x64;SentryWindowsCMakeArch=x64" />
+    <MSBuild Projects="$(MSBuildProjectFullPath)" Targets="_BuildWindowsSDKForArch" Properties="SentryWindowsArch=x86;SentryWindowsCMakeArch=Win32" />
+  </Target>
+
+  <Target Name="_BuildWindowsSDKForArch">
+    <PropertyGroup>
+      <WindowsBuildDir>build_$(SentryWindowsArch)</WindowsBuildDir>
+      <WindowsDestination>$(SentryWindowsArtifactsDestination)$(SentryWindowsArch)/</WindowsDestination>
+    </PropertyGroup>
+
+    <Message Importance="High" Text="Building Sentry Native SDK for Windows $(SentryWindowsArch) (clean rebuild)." />
+
+    <RemoveDir Directories="$(SentryNativeRoot)$(WindowsBuildDir)" ContinueOnError="true" />
 
-    <Exec WorkingDirectory="$(SentryNativeRoot)" Command="cmake -B build -D SENTRY_BACKEND=crashpad -D SENTRY_SDK_NAME=sentry.native.unity -D SENTRY_BUILD_RUNTIMESTATIC=ON -S ." />
-    <Exec WorkingDirectory="$(SentryNativeRoot)" Command="cmake --build build --target sentry --config RelWithDebInfo --parallel" />
-    <Exec WorkingDirectory="$(SentryNativeRoot)" Command="cmake --build build --target crashpad_handler --config Release --parallel" />
+    <Exec WorkingDirectory="$(SentryNativeRoot)" Command="cmake -B $(WindowsBuildDir) -A $(SentryWindowsCMakeArch) -D SENTRY_BACKEND=crashpad -D SENTRY_SDK_NAME=sentry.native.unity -D SENTRY_BUILD_RUNTIMESTATIC=ON -S ." />
+    <Exec WorkingDirectory="$(SentryNativeRoot)" Command="cmake --build $(WindowsBuildDir) --target sentry --config RelWithDebInfo --parallel" />
+    <Exec WorkingDirectory="$(SentryNativeRoot)" Command="cmake --build $(WindowsBuildDir) --target crashpad_handler --config Release --parallel" />
 
-    <MakeDir Directories="$(SentryWindowsArtifactsDestination)" />
+    <MakeDir Directories="$(WindowsDestination)" />
 
     <ItemGroup>
-      <NativeSdkArtifacts Include="$(SentryNativeRoot)build/crashpad_build/handler/Release/crashpad_handler.exe" />
-      <NativeSdkArtifacts Include="$(SentryNativeRoot)build/crashpad_build/handler/RelWithDebInfo/crashpad_wer.dll" />
-      <NativeSdkArtifacts Include="$(SentryNativeRoot)build/crashpad_build/handler/RelWithDebInfo/crashpad_wer.pdb" />
-      <NativeSdkArtifacts Include="$(SentryNativeRoot)build/RelWithDebInfo/sentry.pdb" />
+      <NativeSdkArtifacts Include="$(SentryNativeRoot)$(WindowsBuildDir)/crashpad_build/handler/Release/crashpad_handler.exe" />
+      <NativeSdkArtifacts Include="$(SentryNativeRoot)$(WindowsBuildDir)/crashpad_build/handler/RelWithDebInfo/crashpad_wer.dll" />
+      <NativeSdkArtifacts Include="$(SentryNativeRoot)$(WindowsBuildDir)/crashpad_build/handler/RelWithDebInfo/crashpad_wer.pdb" />
+      <NativeSdkArtifacts Include="$(SentryNativeRoot)$(WindowsBuildDir)/RelWithDebInfo/sentry.pdb" />
     </ItemGroup>
 
-    <Copy SourceFiles="@(NativeSdkArtifacts)" DestinationFolder="$(SentryWindowsArtifactsDestination)" />
-    <Copy SourceFiles="$(SentryNativeRoot)build/RelWithDebInfo/sentry.dll" DestinationFiles="$(SentryWindowsArtifactsDestination)$(SentryWindowsLibraryName)" />
+    <Copy SourceFiles="@(NativeSdkArtifacts)" DestinationFolder="$(WindowsDestination)" />
+    <Copy SourceFiles="$(SentryNativeRoot)$(WindowsBuildDir)/RelWithDebInfo/sentry.dll" DestinationFiles="$(WindowsDestination)$(SentryWindowsLibraryName)" />
 
-    <Error Condition="!Exists('$(SentryWindowsArtifactsDestination)$(SentryWindowsLibraryName)')" Text="Failed to set up the Windows SDK." />
+    <Error Condition="!Exists('$(WindowsDestination)$(SentryWindowsLibraryName)')" Text="Failed to set up the Windows $(SentryWindowsArch) SDK." />
   </Target>
 
   <!--
     Build the Sentry Native SDK for Windows (sentry-native's new native backend):
         dotnet msbuild /t:BuildWindowsNativeSDK src/Sentry.Unity
     Always wipes prior outputs and rebuilds. Produces sentry-native.dll, sentry-crash.exe,
-    and sentry-wer.dll plus their .pdb sidecars.
+    and sentry-wer.dll plus their .pdb sidecars, per architecture.
   -->
   <Target Name="BuildWindowsNativeSDK" Condition="'$(MSBuildProjectName)' == 'Sentry.Unity'">
     <Error Condition="!$([MSBuild]::IsOSPlatform('Windows'))" Text="BuildWindowsNativeSDK can only run on Windows." />
     <Error Condition="!Exists('$(SentryNativeRoot)')" Text="sentry-native submodule not checked out at $(SentryNativeRoot). Run: git submodule update --init modules/sentry-native" />
 
-    <Message Importance="High" Text="Building Sentry Native SDK for Windows (native backend, clean rebuild)." />
+    <RemoveDir Directories="$(SentryWindowsNativeArtifactsDestination)" ContinueOnError="true" />
 
-    <!-- Wipe prior outputs -->
-    <RemoveDir Directories="$(SentryNativeRoot)build_native" ContinueOnError="true" />
-    <Delete Files="$(SentryWindowsNativeArtifactsDestination)sentry.dll" ContinueOnError="true" />
-    <Delete Files="$(SentryWindowsNativeArtifactsDestination)$(SentryWindowsLibraryName)" ContinueOnError="true" />
-    <Delete Files="$(SentryWindowsNativeArtifactsDestination)sentry.pdb" ContinueOnError="true" />
-    <Delete Files="$(SentryWindowsNativeArtifactsDestination)sentry-crash.exe" ContinueOnError="true" />
-    <Delete Files="$(SentryWindowsNativeArtifactsDestination)sentry-crash.pdb" ContinueOnError="true" />
-    <Delete Files="$(SentryWindowsNativeArtifactsDestination)sentry-wer.dll" ContinueOnError="true" />
-    <Delete Files="$(SentryWindowsNativeArtifactsDestination)sentry-wer.pdb" ContinueOnError="true" />
+    <MSBuild Projects="$(MSBuildProjectFullPath)" Targets="_BuildWindowsNativeSDKForArch" Properties="SentryWindowsArch=x64;SentryWindowsCMakeArch=x64" />
+    <MSBuild Projects="$(MSBuildProjectFullPath)" Targets="_BuildWindowsNativeSDKForArch" Properties="SentryWindowsArch=x86;SentryWindowsCMakeArch=Win32" />
+  </Target>
+
+  <Target Name="_BuildWindowsNativeSDKForArch">
+    <PropertyGroup>
+      <WindowsNativeBuildDir>build_native_$(SentryWindowsArch)</WindowsNativeBuildDir>
+      <WindowsNativeDestination>$(SentryWindowsNativeArtifactsDestination)$(SentryWindowsArch)/</WindowsNativeDestination>
+    </PropertyGroup>
+
+    <Message Importance="High" Text="Building Sentry Native SDK for Windows $(SentryWindowsArch) (native backend, clean rebuild)." />
+
+    <RemoveDir Directories="$(SentryNativeRoot)$(WindowsNativeBuildDir)" ContinueOnError="true" />
 
-    <Exec WorkingDirectory="$(SentryNativeRoot)" Command="cmake -B build_native -D SENTRY_BACKEND=native -D SENTRY_SDK_NAME=sentry.native.unity -D SENTRY_BUILD_RUNTIMESTATIC=ON -S ." />
-    <Exec WorkingDirectory="$(SentryNativeRoot)" Command="cmake --build build_native --target sentry --config RelWithDebInfo --parallel" />
-    <Exec WorkingDirectory="$(SentryNativeRoot)" Command="cmake --build build_native --target sentry-crash --config RelWithDebInfo --parallel" />
-    <Exec WorkingDirectory="$(SentryNativeRoot)" Command="cmake --build build_native --target sentry-wer --config RelWithDebInfo --parallel" />
+    <Exec WorkingDirectory="$(SentryNativeRoot)" Command="cmake -B $(WindowsNativeBuildDir) -A $(SentryWindowsCMakeArch) -D SENTRY_BACKEND=native -D SENTRY_SDK_NAME=sentry.native.unity -D SENTRY_BUILD_RUNTIMESTATIC=ON -S ." />
+    <Exec WorkingDirectory="$(SentryNativeRoot)" Command="cmake --build $(WindowsNativeBuildDir) --target sentry --config RelWithDebInfo --parallel" />
+    <Exec WorkingDirectory="$(SentryNativeRoot)" Command="cmake --build $(WindowsNativeBuildDir) --target sentry-crash --config RelWithDebInfo --parallel" />
+    <Exec WorkingDirectory="$(SentryNativeRoot)" Command="cmake --build $(WindowsNativeBuildDir) --target sentry-wer --config RelWithDebInfo --parallel" />
 
-    <MakeDir Directories="$(SentryWindowsNativeArtifactsDestination)" />
+    <MakeDir Directories="$(WindowsNativeDestination)" />
 
     <ItemGroup>
-      <WindowsNativeSdkArtifacts Include="$(SentryNativeRoot)build_native/RelWithDebInfo/sentry.pdb" />
-      <WindowsNativeSdkArtifacts Include="$(SentryNativeRoot)build_native/RelWithDebInfo/sentry-crash.exe" />
-      <WindowsNativeSdkArtifacts Include="$(SentryNativeRoot)build_native/RelWithDebInfo/sentry-crash.pdb" />
-      <WindowsNativeSdkArtifacts Include="$(SentryNativeRoot)build_native/RelWithDebInfo/sentry-wer.dll" />
-      <WindowsNativeSdkArtifacts Include="$(SentryNativeRoot)build_native/RelWithDebInfo/sentry-wer.pdb" />
+      <WindowsNativeSdkArtifacts Include="$(SentryNativeRoot)$(WindowsNativeBuildDir)/RelWithDebInfo/sentry.pdb" />
+      <WindowsNativeSdkArtifacts Include="$(SentryNativeRoot)$(WindowsNativeBuildDir)/RelWithDebInfo/sentry-crash.exe" />
+      <WindowsNativeSdkArtifacts Include="$(SentryNativeRoot)$(WindowsNativeBuildDir)/RelWithDebInfo/sentry-crash.pdb" />
+      <WindowsNativeSdkArtifacts Include="$(SentryNativeRoot)$(WindowsNativeBuildDir)/RelWithDebInfo/sentry-wer.dll" />
+      <WindowsNativeSdkArtifacts Include="$(SentryNativeRoot)$(WindowsNativeBuildDir)/RelWithDebInfo/sentry-wer.pdb" />
     </ItemGroup>
 
-    <Copy SourceFiles="@(WindowsNativeSdkArtifacts)" DestinationFolder="$(SentryWindowsNativeArtifactsDestination)" />
-    <Copy SourceFiles="$(SentryNativeRoot)build_native/RelWithDebInfo/sentry.dll" DestinationFiles="$(SentryWindowsNativeArtifactsDestination)$(SentryWindowsLibraryName)" />
+    <Copy SourceFiles="@(WindowsNativeSdkArtifacts)" DestinationFolder="$(WindowsNativeDestination)" />
+    <Copy SourceFiles="$(SentryNativeRoot)$(WindowsNativeBuildDir)/RelWithDebInfo/sentry.dll" DestinationFiles="$(WindowsNativeDestination)$(SentryWindowsLibraryName)" />
 
-    <Error Condition="!Exists('$(SentryWindowsNativeArtifactsDestination)$(SentryWindowsLibraryName)')" Text="Failed to set up the Windows Native SDK." />
+    <Error Condition="!Exists('$(WindowsNativeDestination)$(SentryWindowsLibraryName)')" Text="Failed to set up the Windows $(SentryWindowsArch) Native SDK." />
   </Target>
 
   <!--
diff --git a/docs/agent-guides/platform-native.md b/docs/agent-guides/platform-native.md
index a51899c62..bc5fbe157 100644
--- a/docs/agent-guides/platform-native.md
+++ b/docs/agent-guides/platform-native.md
@@ -24,7 +24,9 @@ Experimental native modes raise minimum shutdown timeout to 10 seconds.
 
 `Sentry.Unity.Editor/Native/BuildPostProcess.cs` selects legacy `Sentry~` or experimental `SentryNative~`, clears stale handler artifacts when switching backend, copies runtime libraries to player locations, and leaves symbols in package for upload.
 
-- Windows: runtime files beside player `.exe`; the library lands as `sentry-native.dll`.
+- Windows: runtime files beside player `.exe`; the library lands as `sentry-native.dll`. Both
+  architectures ship, under `x86/` and `x64/` inside each backend folder, because Unity still
+  builds a 32-bit standalone player. `BuildTarget.StandaloneWindows` picks `x86/`.
 - Linux: `libsentry-native.so` under `<Player>_Data/Plugins/x86_64`; native daemon beside executable.
 - macOS: `libsentry-native.dylib` in `.app/Contents/PlugIns`; handler in `.app/Contents/MacOS`. Cocoa's `Sentry.dylib` keeps its name, it is dlopened not P/Invoked.
 - Post-build copies names through unchanged; stale cleanup wipes pre-rename names.
diff --git a/package-dev/Plugins/Switch/SentryStub~/sentry_native_stubs.c b/package-dev/Plugins/Switch/SentryStub~/sentry_native_stubs.c
index 6786716c9..d85ce5de9 100644
--- a/package-dev/Plugins/Switch/SentryStub~/sentry_native_stubs.c
+++ b/package-dev/Plugins/Switch/SentryStub~/sentry_native_stubs.c
@@ -24,6 +24,14 @@ typedef union {
 /* Null value constant */
 static const sentry_value_t SENTRY_VALUE_NULL = {0};
 
+/* sentry_uuid_t is a 16-byte struct in sentry-native */
+typedef struct {
+    char bytes[16];
+} sentry_uuid_t;
+
+/* Nil UUID, returned by sentry-native when an attachment is not added */
+static const sentry_uuid_t SENTRY_UUID_NIL = {{0}};
+
 /*
  * =============================================================================
  * sentry-native Core Functions
@@ -300,18 +308,18 @@ void sentry_set_environment(const char* environment)
     (void)environment;
 }
 
-void* sentry_attach_file(const char* path)
+sentry_uuid_t sentry_attach_file(const char* path)
 {
     (void)path;
-    return NULL;
+    return SENTRY_UUID_NIL;
 }
 
-void* sentry_attach_bytes(const char* buffer, size_t buffer_length, const char* filename)
+sentry_uuid_t sentry_attach_bytes(const char* buffer, size_t buffer_length, const char* filename)
 {
     (void)buffer;
     (void)buffer_length;
     (void)filename;
-    return NULL;
+    return SENTRY_UUID_NIL;
 }
 
 void sentry_clear_attachments(void)
diff --git a/scripts/download-native-sdks.ps1 b/scripts/download-native-sdks.ps1
index 2764e0f76..efccd359d 100644
--- a/scripts/download-native-sdks.ps1
+++ b/scripts/download-native-sdks.ps1
@@ -16,12 +16,18 @@ $SDKs = @(
     @{
         Name = "Windows"
         Destination = Join-Path $ArtifactsDestination "Windows/Sentry~"
-        CheckFile = "sentry-native.dll"
+        CheckFiles = @(
+            "x64/sentry-native.dll",
+            "x86/sentry-native.dll"
+        )
     },
     @{
         Name = "WindowsNative"
         Destination = Join-Path $ArtifactsDestination "Windows/SentryNative~"
-        CheckFile = "sentry-native.dll"
+        CheckFiles = @(
+            "x64/sentry-native.dll",
+            "x86/sentry-native.dll"
+        )
     },
     @{
         Name = "Linux"
diff --git a/src/Sentry.Unity.Editor/Native/BuildPostProcess.cs b/src/Sentry.Unity.Editor/Native/BuildPostProcess.cs
index fd943e7c8..0b8592b18 100644
--- a/src/Sentry.Unity.Editor/Native/BuildPostProcess.cs
+++ b/src/Sentry.Unity.Editor/Native/BuildPostProcess.cs
@@ -144,6 +144,15 @@ _ when target.IsSwitch2() => options.SwitchNativeSupportEnabled,
     internal const string LinuxLibraryName = "libsentry-native.so";
     internal const string MacOSLibraryName = "libsentry-native.dylib";
 
+    // Windows ships both architectures. Unity still builds a 32-bit standalone player and it cannot
+    // load the x64 library, so `native-sdks.targets` writes each backend into an `x86`/`x64` subfolder.
+    internal static string GetWindowsBackendDir(BuildTarget target, SentryUnityOptions options)
+    {
+        var backend = options.Experimental.WindowsBackend == WindowsBackend.Native ? "SentryNative~" : "Sentry~";
+        var arch = target == BuildTarget.StandaloneWindows ? "x86" : "x64";
+        return Path.GetFullPath($"Packages/{SentryPackageInfo.GetName()}/Plugins/Windows/{backend}/{arch}");
+    }
+
     private readonly struct NativePluginArtifact(string source, string destination, bool isExecutable = false)
     {
         public readonly string Source = source;
@@ -160,9 +169,7 @@ private static IEnumerable<NativePluginArtifact> GetNativePluginArtifact(
         {
             case BuildTarget.StandaloneWindows:
             case BuildTarget.StandaloneWindows64:
-                var windowsBackendSourcePath = options.Experimental.WindowsBackend == WindowsBackend.Native
-                    ? Path.Combine(pluginsPath, "Windows", "SentryNative~")
-                    : Path.Combine(pluginsPath, "Windows", "Sentry~");
+                var windowsBackendSourcePath = GetWindowsBackendDir(target, options);
                 if (!Directory.Exists(windowsBackendSourcePath))
                 {
                     var buildTarget = options.Experimental.WindowsBackend == WindowsBackend.Native ? "BuildWindowsNativeSDK" : "BuildWindowsSDK";
@@ -392,11 +399,7 @@ private static void UploadDebugSymbols(IDiagnosticLogger logger, BuildTarget tar
                 // Sentry native SDK symbols from package.
                 // Glob *.pdb from whichever backend's source dir is in use, so adding
                 // or removing PDBs at build time doesn't require touching this code.
-                var windowsBackendDir = options.Experimental.WindowsBackend == WindowsBackend.Native
-                    ? "SentryNative~"
-                    : "Sentry~";
-                var windowsPdbDir = Path.GetFullPath(
-                    $"Packages/{SentryPackageInfo.GetName()}/Plugins/Windows/{windowsBackendDir}");
+                var windowsPdbDir = GetWindowsBackendDir(target, options);
                 if (Directory.Exists(windowsPdbDir))
                 {
                     foreach (var pdb in Directory.GetFiles(windowsPdbDir, "*.pdb"))
diff --git a/src/Sentry.Unity.Native/CFunctions.cs b/src/Sentry.Unity.Native/CFunctions.cs
index ec7a27909..0d13f5a8d 100644
--- a/src/Sentry.Unity.Native/CFunctions.cs
+++ b/src/Sentry.Unity.Native/CFunctions.cs
@@ -87,90 +87,90 @@ internal static void SetValueIfNotNull(sentry_value_t obj, string key, long? val
         return null;
     }
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern sentry_value_t sentry_value_new_object();
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern sentry_value_t sentry_value_new_null();
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern sentry_value_t sentry_value_new_bool(int value);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern sentry_value_t sentry_value_new_double(double value);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern sentry_value_t sentry_value_new_int32(int value);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern sentry_value_t sentry_value_new_string(string value);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern sentry_value_t sentry_value_new_breadcrumb(string? type, string? message);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern int sentry_value_set_by_key(sentry_value_t value, string k, sentry_value_t v);
 
     internal static bool IsNull(sentry_value_t value) => sentry_value_is_null(value) != 0;
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern int sentry_value_is_null(sentry_value_t value);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern int sentry_value_as_int32(sentry_value_t value);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern double sentry_value_as_double(sentry_value_t value);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern IntPtr sentry_value_as_string(sentry_value_t value);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern UIntPtr sentry_value_get_length(sentry_value_t value);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern sentry_value_t sentry_value_get_by_index(sentry_value_t value, UIntPtr index);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern sentry_value_t sentry_value_get_by_key(sentry_value_t value, string key);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern void sentry_set_context(string key, sentry_value_t value);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern void sentry_add_breadcrumb(sentry_value_t breadcrumb);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern void sentry_set_tag(string key, string value);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern void sentry_remove_tag(string key);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern void sentry_set_user(sentry_value_t user);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern void sentry_remove_user();
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern void sentry_set_extra(string key, sentry_value_t value);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern void sentry_remove_extra(string key);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern void sentry_set_trace(string traceId, string parentSpanId);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern void sentry_set_environment(string? environment);
 
-    [DllImport(SentryLib)]
-    internal static extern IntPtr sentry_attach_file(string path);
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
+    internal static extern sentry_uuid_t sentry_attach_file(string path);
 
-    [DllImport(SentryLib)]
-    internal static extern IntPtr sentry_attach_bytes(byte[] buf, UIntPtr buf_len, string filename);
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
+    internal static extern sentry_uuid_t sentry_attach_bytes(byte[] buf, UIntPtr buf_len, string filename);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern void sentry_clear_attachments();
 
     internal static readonly Lazy<IEnumerable<DebugImage>> DebugImages = new(LoadDebugImages);
@@ -224,10 +224,10 @@ private static IEnumerable<DebugImage> LoadDebugImages()
 
     // Returns a new reference to an immutable, frozen list.
     // The reference must be released with `sentry_value_decref`.
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern sentry_value_t sentry_get_modules_list();
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     internal static extern int sentry_value_decref(sentry_value_t value);
 
     // native union sentry_value_u/t
@@ -240,4 +240,12 @@ internal struct sentry_value_t
         internal double _double;
     }
 
+    // native struct sentry_uuid_s/t (char bytes[16])
+    [StructLayout(LayoutKind.Sequential)]
+    internal struct sentry_uuid_t
+    {
+        internal ulong _low;
+        internal ulong _high;
+    }
+
 }
diff --git a/src/Sentry.Unity.Native/SentryNativeBridge.cs b/src/Sentry.Unity.Native/SentryNativeBridge.cs
index 46d5baca6..36b868dde 100644
--- a/src/Sentry.Unity.Native/SentryNativeBridge.cs
+++ b/src/Sentry.Unity.Native/SentryNativeBridge.cs
@@ -157,57 +157,57 @@ internal static string GetDatabasePath(SentryUnityOptions options, IApplication?
 
     internal static void AppHangPause() => sentry_app_hang_pause();
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern IntPtr sentry_options_new();
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_options_set_dsn(IntPtr options, string dsn);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_options_set_release(IntPtr options, string release);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_options_set_debug(IntPtr options, int debug);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_options_set_environment(IntPtr options, string environment);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_options_set_sample_rate(IntPtr options, double rate);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_options_set_database_path(IntPtr options, string path);
 
 #if !SENTRY_NATIVE_SWITCH
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_options_set_database_pathw(IntPtr options, [MarshalAs(UnmanagedType.LPWStr)] string path);
 #endif
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_options_set_auto_session_tracking(IntPtr options, int debug);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_options_set_attach_screenshot(IntPtr options, int attachScreenshot);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_options_set_shutdown_timeout(IntPtr options, ulong shutdown_timeout);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_options_set_enable_app_hang_tracking(IntPtr options, int enabled);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_options_set_app_hang_timeout(IntPtr options, ulong timeout);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_app_hang_pause();
 
     [UnmanagedFunctionPointer(CallingConvention.Cdecl, SetLastError = true)]
     private delegate void sentry_logger_function_t(int level, IntPtr message, IntPtr argsAddress, IntPtr userData);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_options_set_logger(IntPtr options, sentry_logger_function_t logger, IntPtr userData);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_options_set_logger_enabled_when_crashed(IntPtr options, int enabled);
 
     // This method is called from the C library and forwards incoming messages to the currently set _logger.
@@ -298,14 +298,14 @@ private static void nativeLogImpl(int cLevel, IntPtr format, IntPtr args, IntPtr
     }
 
 #if SENTRY_NATIVE_PLAYSTATION || SENTRY_NATIVE_SWITCH
-    [DllImport("__Internal", EntryPoint = "vsnprintf_sentry")]
+    [DllImport("__Internal", EntryPoint = "vsnprintf_sentry", CallingConvention = CallingConvention.Cdecl)]
     private static extern int vsnprintf_sentry(IntPtr buffer, UIntPtr bufferSize, IntPtr format, IntPtr args);
 #else
     // For Windows/Linux: use platform's native C library directly
-    [DllImport("msvcrt", EntryPoint = "vsnprintf")]
+    [DllImport("msvcrt", EntryPoint = "vsnprintf", CallingConvention = CallingConvention.Cdecl)]
     private static extern int vsnprintf_windows(IntPtr buffer, UIntPtr bufferSize, IntPtr format, IntPtr args);
 
-    [DllImport("libc", EntryPoint = "vsnprintf")]
+    [DllImport("libc", EntryPoint = "vsnprintf", CallingConvention = CallingConvention.Cdecl)]
     private static extern int vsnprintf_linux(IntPtr buffer, UIntPtr bufferSize, IntPtr format, IntPtr args);
 #endif
 
@@ -351,18 +351,18 @@ private static void WithMarshalledStruct<T>(T structure, Action<IntPtr> action)
             action(ptr);
         });
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern int sentry_init(IntPtr options);
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern int sentry_close();
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern int sentry_get_crashed_last_run();
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_reinstall_backend();
 
-    [DllImport(SentryLib)]
+    [DllImport(SentryLib, CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_app_hang_heartbeat();
 }
diff --git a/src/Sentry.Unity.Native/SentryNativeSwitch.cs b/src/Sentry.Unity.Native/SentryNativeSwitch.cs
index b01a93ce5..cb0ab3f25 100644
--- a/src/Sentry.Unity.Native/SentryNativeSwitch.cs
+++ b/src/Sentry.Unity.Native/SentryNativeSwitch.cs
@@ -13,22 +13,22 @@ namespace Sentry.Unity.Native;
 public static class SentryNativeSwitch
 {
     // P/Invoke to sentry_switch_utils.cpp
-    [DllImport("__Internal")]
+    [DllImport("__Internal", CallingConvention = CallingConvention.Cdecl)]
     private static extern int sentry_switch_utils_mount();
 
-    [DllImport("__Internal")]
+    [DllImport("__Internal", CallingConvention = CallingConvention.Cdecl)]
     private static extern IntPtr sentry_switch_utils_get_cache_path();
 
-    [DllImport("__Internal")]
+    [DllImport("__Internal", CallingConvention = CallingConvention.Cdecl)]
     private static extern int sentry_switch_utils_is_mounted();
 
-    [DllImport("__Internal")]
+    [DllImport("__Internal", CallingConvention = CallingConvention.Cdecl)]
     private static extern void sentry_switch_utils_unmount();
 
-    [DllImport("__Internal")]
+    [DllImport("__Internal", CallingConvention = CallingConvention.Cdecl)]
     private static extern IntPtr sentry_switch_utils_get_default_user_id();
 
-    [DllImport("__Internal")]
+    [DllImport("__Internal", CallingConvention = CallingConvention.Cdecl)]
     private static extern int sentry_switch_utils_is_network_available();
 
     private static IDiagnosticLogger? Logger;
diff --git a/src/Sentry.Unity.Native/SentryNativeXbox.cs b/src/Sentry.Unity.Native/SentryNativeXbox.cs
index fb67c850f..6f87d0225 100644
--- a/src/Sentry.Unity.Native/SentryNativeXbox.cs
+++ b/src/Sentry.Unity.Native/SentryNativeXbox.cs
@@ -15,7 +15,7 @@ namespace Sentry.Unity.Native;
 /// </remarks>
 internal static class SentryNativeXbox
 {
-    [DllImport("sentry")]
+    [DllImport("sentry", CallingConvention = CallingConvention.Cdecl)]
     private static extern IntPtr sentry_xbox_utils_get_pls_path();
 
     /// <summary>
diff --git a/test/Scripts.Integration.Test/Editor/Builder.cs b/test/Scripts.Integration.Test/Editor/Builder.cs
index f4a967045..3fb577721 100644
--- a/test/Scripts.Integration.Test/Editor/Builder.cs
+++ b/test/Scripts.Integration.Test/Editor/Builder.cs
@@ -126,6 +126,14 @@ public static void BuildWindowsIl2CPPPlayer()
             defaultBuildPath: "./Builds/Windows/test.exe");
     }
 
+    [MenuItem("Tools/Builder/Windows x86")]
+    public static void BuildWindowsX86Il2CPPPlayer()
+    {
+        Debug.Log("Builder: Building Windows x86 IL2CPP Player");
+        BuildIl2CPPPlayer(BuildTarget.StandaloneWindows, BuildTargetGroup.Standalone, BuildOptions.StrictMode,
+            defaultBuildPath: "./Builds/Windows/test.exe");
+    }
+
     [MenuItem("Tools/Builder/Windows Mono")]
     public static void BuildWindowsMonoPlayer()
     {
diff --git a/test/Scripts.Integration.Test/globals.ps1 b/test/Scripts.Integration.Test/globals.ps1
index 805004bff..275438f5d 100644
--- a/test/Scripts.Integration.Test/globals.ps1
+++ b/test/Scripts.Integration.Test/globals.ps1
@@ -148,6 +148,7 @@ function BuildMethodFor([string] $platform)
         "Android-Export" { return "Builder.BuildAndroidIl2CPPProject" }
         "MacOS" { return "Builder.BuildMacIl2CPPPlayer" }
         "Windows" { return "Builder.BuildWindowsIl2CPPPlayer" }
+        "Windows-x86" { return "Builder.BuildWindowsX86Il2CPPPlayer" }
         "Windows-Mono" { return "Builder.BuildWindowsMonoPlayer" }
         "Linux" { return "Builder.BuildLinuxIl2CPPPlayer" }
         "WebGL" { return "Builder.BuildWebGLPlayer" }
diff --git a/test/Scripts.Tests/package-release.zip.snapshot b/test/Scripts.Tests/package-release.zip.snapshot
index 4af463a73..cda6e92ef 100644
--- a/test/Scripts.Tests/package-release.zip.snapshot
+++ b/test/Scripts.Tests/package-release.zip.snapshot
@@ -280,17 +280,30 @@ Plugins/Android/Sentry~/sentry-android-ndk-release.aar
 Plugins/Android/Sentry~/sentry-native-ndk-release.aar
 Plugins/Android/Sentry~/sentry.jar
 Plugins/Switch/SentryStub~/sentry_native_stubs.c
-Plugins/Windows/SentryNative~/sentry-crash.exe
-Plugins/Windows/SentryNative~/sentry-crash.pdb
-Plugins/Windows/SentryNative~/sentry-native.dll
-Plugins/Windows/SentryNative~/sentry-wer.dll
-Plugins/Windows/SentryNative~/sentry-wer.pdb
-Plugins/Windows/SentryNative~/sentry.pdb
-Plugins/Windows/Sentry~/crashpad_handler.exe
-Plugins/Windows/Sentry~/crashpad_wer.dll
-Plugins/Windows/Sentry~/crashpad_wer.pdb
-Plugins/Windows/Sentry~/sentry-native.dll
-Plugins/Windows/Sentry~/sentry.pdb
+Plugins/Windows/Sentry~/
+Plugins/Windows/SentryNative~/
+Plugins/Windows/SentryNative~/x64/sentry-crash.exe
+Plugins/Windows/SentryNative~/x64/sentry-crash.pdb
+Plugins/Windows/SentryNative~/x64/sentry-wer.dll
+Plugins/Windows/SentryNative~/x64/sentry-wer.pdb
+Plugins/Windows/SentryNative~/x64/sentry-native.dll
+Plugins/Windows/SentryNative~/x64/sentry.pdb
+Plugins/Windows/SentryNative~/x86/sentry-crash.exe
+Plugins/Windows/SentryNative~/x86/sentry-crash.pdb
+Plugins/Windows/SentryNative~/x86/sentry-wer.dll
+Plugins/Windows/SentryNative~/x86/sentry-wer.pdb
+Plugins/Windows/SentryNative~/x86/sentry-native.dll
+Plugins/Windows/SentryNative~/x86/sentry.pdb
+Plugins/Windows/Sentry~/x64/crashpad_handler.exe
+Plugins/Windows/Sentry~/x64/crashpad_wer.dll
+Plugins/Windows/Sentry~/x64/crashpad_wer.pdb
+Plugins/Windows/Sentry~/x64/sentry-native.dll
+Plugins/Windows/Sentry~/x64/sentry.pdb
+Plugins/Windows/Sentry~/x86/crashpad_handler.exe
+Plugins/Windows/Sentry~/x86/crashpad_wer.dll
+Plugins/Windows/Sentry~/x86/crashpad_wer.pdb
+Plugins/Windows/Sentry~/x86/sentry-native.dll
+Plugins/Windows/Sentry~/x86/sentry.pdb
 Prefabs/SentryUserFeedback.prefab
 Prefabs/SentryUserFeedback.prefab.meta
 Runtime/io.sentry.unity.runtime.asmdef
diff --git a/test/Sentry.Unity.Editor.Tests/Native/BuildPostProcessTests.cs b/test/Sentry.Unity.Editor.Tests/Native/BuildPostProcessTests.cs
index 69fa286bf..c8817cfbc 100644
--- a/test/Sentry.Unity.Editor.Tests/Native/BuildPostProcessTests.cs
+++ b/test/Sentry.Unity.Editor.Tests/Native/BuildPostProcessTests.cs
@@ -5,6 +5,7 @@
 using NUnit.Framework;
 using Sentry.Unity.Editor.Native;
 using Sentry.Unity.Tests.SharedClasses;
+using UnityEditor;
 
 namespace Sentry.Unity.Editor.Tests.Native;
 
@@ -80,4 +81,20 @@ public void AddPath_RequiredPathMissing_LogsWarning()
             l.logLevel == SentryLevel.Warning &&
             l.message.Contains("Required path not found")));
     }
+
+    [TestCase(BuildTarget.StandaloneWindows, WindowsBackend.Crashpad, "Sentry~", "x86")]
+    [TestCase(BuildTarget.StandaloneWindows64, WindowsBackend.Crashpad, "Sentry~", "x64")]
+    [TestCase(BuildTarget.StandaloneWindows, WindowsBackend.Native, "SentryNative~", "x86")]
+    [TestCase(BuildTarget.StandaloneWindows64, WindowsBackend.Native, "SentryNative~", "x64")]
+    public void GetWindowsBackendDir_ResolvesBackendAndArchitecture(
+        BuildTarget target, WindowsBackend backend, string expectedBackendDir, string expectedArchDir)
+    {
+        var options = new SentryUnityOptions();
+        options.Experimental.WindowsBackend = backend;
+
+        var actual = BuildPostProcess.GetWindowsBackendDir(target, options);
+
+        Assert.AreEqual(expectedArchDir, Path.GetFileName(actual));
+        Assert.AreEqual(expectedBackendDir, Path.GetFileName(Path.GetDirectoryName(actual)));
+    }
 }