diff --git a/src/LibHac/Fs/PathTools.cs b/src/LibHac/Fs/PathTools.cs
index 97dc2a76..538bd218 100644
--- a/src/LibHac/Fs/PathTools.cs
+++ b/src/LibHac/Fs/PathTools.cs
@@ -13,6 +13,7 @@ namespace LibHac.Fs
         public static readonly char DirectorySeparator = '/';
         public static readonly char MountSeparator = ':';
         internal const int MountNameLength = 0xF;
+        internal const int MaxPathLength = 0x300;
 
         public static string Normalize(string inPath)
         {
diff --git a/src/LibHac/FsService/Creators/ISaveDataFileSystemCreator.cs b/src/LibHac/FsService/Creators/ISaveDataFileSystemCreator.cs
index 4cd3b224..335d65e2 100644
--- a/src/LibHac/FsService/Creators/ISaveDataFileSystemCreator.cs
+++ b/src/LibHac/FsService/Creators/ISaveDataFileSystemCreator.cs
@@ -13,6 +13,6 @@ namespace LibHac.FsService.Creators
             IFileSystem sourceFileSystem, ulong saveDataId, bool allowDirectorySaveData, bool useDeviceUniqueMac,
             SaveDataType type, ITimeStampGenerator timeStampGenerator);
 
-        Result SetSdCardEncryptionSeed(ReadOnlySpan<byte> seed);
+        void SetSdCardEncryptionSeed(ReadOnlySpan<byte> seed);
     }
 }
diff --git a/src/LibHac/FsService/FileSystemProxy.cs b/src/LibHac/FsService/FileSystemProxy.cs
new file mode 100644
index 00000000..0b7baf0e
--- /dev/null
+++ b/src/LibHac/FsService/FileSystemProxy.cs
@@ -0,0 +1,93 @@
+using System;
+using LibHac.Fs;
+
+namespace LibHac.FsService
+{
+    public class FileSystemProxy
+    {
+        private FileSystemProxyCore FsProxyCore { get; }
+        public long CurrentProcess { get; private set; }
+
+        public long SaveDataSize { get; private set; }
+        public long SaveDataJournalSize { get; private set; }
+        public string SaveDataRootPath { get; private set; }
+        public bool AutoCreateSaveData { get; private set; }
+
+        public Result SetCurrentProcess(long processId)
+        {
+            CurrentProcess = processId;
+
+            return Result.Success;
+        }
+
+        public Result DisableAutoSaveDataCreation()
+        {
+            AutoCreateSaveData = false;
+
+            return Result.Success;
+        }
+
+        public Result SetSaveDataSize(long saveDataSize, long saveDataJournalSize)
+        {
+            if (saveDataSize < 0 || saveDataJournalSize < 0)
+            {
+                return ResultFs.InvalidSize;
+            }
+
+            SaveDataSize = saveDataSize;
+            SaveDataJournalSize = saveDataJournalSize;
+
+            return Result.Success;
+        }
+
+        public Result SetSaveDataRootPath(string path)
+        {
+            // Missing permission check
+
+            if (path.Length > PathTools.MaxPathLength)
+            {
+                return ResultFs.TooLongPath;
+            }
+
+            SaveDataRootPath = path;
+
+            return Result.Success;
+        }
+
+        public Result OpenBisFileSystem(out IFileSystem fileSystem, string rootPath, BisPartitionId partitionId)
+        {
+            // Missing permission check, speed emulation storage type wrapper, and FileSystemInterfaceAdapter
+
+            return FsProxyCore.OpenBisFileSystem(out fileSystem, rootPath, partitionId);
+        }
+
+        public Result OpenSdCardFileSystem(out IFileSystem fileSystem)
+        {
+            // Missing permission check, speed emulation storage type wrapper, and FileSystemInterfaceAdapter
+
+            return FsProxyCore.OpenSdCardFileSystem(out fileSystem);
+        }
+
+        public Result OpenContentStorageFileSystem(out IFileSystem fileSystem, ContentStorageId storageId)
+        {
+            // Missing permission check, speed emulation storage type wrapper, and FileSystemInterfaceAdapter
+
+            return FsProxyCore.OpenContentStorageFileSystem(out fileSystem, storageId);
+        }
+
+        public Result SetSdCardEncryptionSeed(ReadOnlySpan<byte> seed)
+        {
+            // todo: use struct instead of byte span
+            if (seed.Length != 0x16) return ResultFs.InvalidSize;
+
+            // Missing permission check
+
+            Result res = FsProxyCore.SetSdCardEncryptionSeed(seed);
+            if (res.IsFailure()) return res;
+
+            // todo: Reset save data indexer
+
+            return Result.Success;
+        }
+    }
+}
diff --git a/src/LibHac/FsService/FileSystemProxyCore.cs b/src/LibHac/FsService/FileSystemProxyCore.cs
new file mode 100644
index 00000000..25c486c0
--- /dev/null
+++ b/src/LibHac/FsService/FileSystemProxyCore.cs
@@ -0,0 +1,85 @@
+using System;
+using LibHac.Fs;
+using LibHac.FsService.Creators;
+
+namespace LibHac.FsService
+{
+    public class FileSystemProxyCore
+    {
+        private FileSystemCreators FsCreators { get; }
+        private byte[] SdEncryptionSeed { get; } = new byte[0x10];
+
+        private const string NintendoDirectoryName = "Nintendo";
+        private const string ContentDirectoryName = "Contents";
+
+        public FileSystemProxyCore(FileSystemCreators fsCreators)
+        {
+            FsCreators = fsCreators;
+        }
+
+        public Result OpenBisFileSystem(out IFileSystem fileSystem, string rootPath, BisPartitionId partitionId)
+        {
+            return FsCreators.BuiltInStorageFileSystemCreator.Create(out fileSystem, rootPath, partitionId);
+        }
+
+        public Result OpenSdCardFileSystem(out IFileSystem fileSystem)
+        {
+            return FsCreators.SdFileSystemCreator.Create(out fileSystem);
+        }
+
+        public Result OpenContentStorageFileSystem(out IFileSystem fileSystem, ContentStorageId storageId)
+        {
+            fileSystem = default;
+
+            string contentDirPath = default;
+            IFileSystem baseFileSystem = default;
+            bool isEncrypted = false;
+            Result baseFsResult;
+
+            switch (storageId)
+            {
+                case ContentStorageId.System:
+                    baseFsResult = OpenBisFileSystem(out baseFileSystem, string.Empty, BisPartitionId.System);
+                    contentDirPath = $"/{ContentDirectoryName}";
+                    break;
+                case ContentStorageId.User:
+                    baseFsResult = OpenBisFileSystem(out baseFileSystem, string.Empty, BisPartitionId.User);
+                    contentDirPath = $"/{ContentDirectoryName}";
+                    break;
+                case ContentStorageId.SdCard:
+                    baseFsResult = OpenSdCardFileSystem(out baseFileSystem);
+                    contentDirPath = $"/{NintendoDirectoryName}/{ContentDirectoryName}";
+                    isEncrypted = true;
+                    break;
+                default:
+                    baseFsResult = ResultFs.InvalidArgument;
+                    break;
+            }
+
+            if (baseFsResult.IsFailure()) return baseFsResult;
+
+            baseFileSystem.EnsureDirectoryExists(contentDirPath);
+
+            Result subFsResult = FsCreators.SubDirectoryFileSystemCreator.Create(out IFileSystem subDirFileSystem,
+                baseFileSystem, contentDirPath);
+            if (subFsResult.IsFailure()) return subFsResult;
+
+            if (!isEncrypted)
+            {
+                fileSystem = subDirFileSystem;
+                return Result.Success;
+            }
+
+            return FsCreators.EncryptedFileSystemCreator.Create(out fileSystem, subDirFileSystem,
+                EncryptedFsKeyId.Content, SdEncryptionSeed);
+        }
+
+        public Result SetSdCardEncryptionSeed(ReadOnlySpan<byte> seed)
+        {
+            seed.CopyTo(SdEncryptionSeed);
+            FsCreators.SaveDataFileSystemCreator.SetSdCardEncryptionSeed(seed);
+
+            return Result.Success;
+        }
+    }
+}
diff --git a/src/LibHac/FsService/FileSystemService.cs b/src/LibHac/FsService/FileSystemService.cs
new file mode 100644
index 00000000..121cd31e
--- /dev/null
+++ b/src/LibHac/FsService/FileSystemService.cs
@@ -0,0 +1,6 @@
+namespace LibHac.FsService
+{
+    public class FileSystemService
+    {
+    }
+}