diff --git a/lib/models/attachment.dart b/lib/models/attachment.dart
index 5df54b6..bd95afb 100644
--- a/lib/models/attachment.dart
+++ b/lib/models/attachment.dart
@@ -1,5 +1,30 @@
 import 'package:solian/models/account.dart';
 
+class AttachmentPlaceholder {
+  int chunkCount;
+  int chunkSize;
+  Attachment meta;
+
+  AttachmentPlaceholder({
+    required this.chunkCount,
+    required this.chunkSize,
+    required this.meta,
+  });
+
+  factory AttachmentPlaceholder.fromJson(Map<String, dynamic> json) =>
+      AttachmentPlaceholder(
+        chunkCount: json['chunk_count'],
+        chunkSize: json['chunk_size'],
+        meta: Attachment.fromJson(json['meta']),
+      );
+
+  Map<String, dynamic> toJson() => {
+        'chunk_count': chunkCount,
+        'chunk_size': chunkSize,
+        'meta': meta.toJson(),
+      };
+}
+
 class Attachment {
   int id;
   DateTime createdAt;
@@ -14,7 +39,9 @@ class Attachment {
   String hash;
   int destination;
   bool isAnalyzed;
+  bool isUploaded;
   Map<String, dynamic>? metadata;
+  Map<String, dynamic>? fileChunks;
   bool isMature;
   Account? account;
   int? accountId;
@@ -33,7 +60,9 @@ class Attachment {
     required this.hash,
     required this.destination,
     required this.isAnalyzed,
+    required this.isUploaded,
     required this.metadata,
+    required this.fileChunks,
     required this.isMature,
     required this.account,
     required this.accountId,
@@ -55,7 +84,9 @@ class Attachment {
         hash: json['hash'],
         destination: json['destination'],
         isAnalyzed: json['is_analyzed'],
+        isUploaded: json['is_uploaded'],
         metadata: json['metadata'],
+        fileChunks: json['file_chunks'],
         isMature: json['is_mature'],
         account:
             json['account'] != null ? Account.fromJson(json['account']) : null,
@@ -76,7 +107,9 @@ class Attachment {
         'hash': hash,
         'destination': destination,
         'is_analyzed': isAnalyzed,
+        'is_uploaded': isUploaded,
         'metadata': metadata,
+        'file_chunks': fileChunks,
         'is_mature': isMature,
         'account': account?.toJson(),
         'account_id': accountId,
diff --git a/lib/providers/attachment_uploader.dart b/lib/providers/attachment_uploader.dart
index e8f643a..9945ee9 100644
--- a/lib/providers/attachment_uploader.dart
+++ b/lib/providers/attachment_uploader.dart
@@ -1,15 +1,17 @@
 import 'dart:async';
-import 'dart:io';
 import 'dart:typed_data';
 
+import 'package:cross_file/cross_file.dart';
 import 'package:get/get.dart';
+import 'package:path/path.dart' show basename;
 import 'package:solian/models/attachment.dart';
 import 'package:solian/providers/content/attachment.dart';
 
 class AttachmentUploadTask {
-  File file;
-  String usage;
+  XFile file;
+  String pool;
   Map<String, dynamic>? metadata;
+  Map<String, int>? chunkFiles;
 
   double progress = 0;
   bool isUploading = false;
@@ -18,7 +20,7 @@ class AttachmentUploadTask {
 
   AttachmentUploadTask({
     required this.file,
-    required this.usage,
+    required this.pool,
     this.metadata,
   });
 }
@@ -75,30 +77,33 @@ class AttachmentUploaderController extends GetxController {
     queueOfUpload[queueIndex].isUploading = true;
 
     final task = queueOfUpload[queueIndex];
-    final result = await _rawUploadAttachment(
-      await task.file.readAsBytes(),
-      task.file.path,
-      task.usage,
-      null,
-      onProgress: (value) {
-        queueOfUpload[queueIndex].progress = value;
-        _progressOfUpload = value;
-      },
-      onError: (err) {
-        queueOfUpload[queueIndex].error = err;
-        queueOfUpload[queueIndex].isUploading = false;
-      },
-    );
+    try {
+      final result = await _chunkedUploadAttachment(
+        task.file,
+        task.pool,
+        null,
+        onData: (_) {},
+        onProgress: (progress) {
+          queueOfUpload[queueIndex].progress = progress;
+          _progressOfUpload = progress;
+        },
+      );
+      return result;
+    } catch (err) {
+      queueOfUpload[queueIndex].error = err;
+      queueOfUpload[queueIndex].isUploading = false;
+    } finally {
+      _progressOfUpload = 1;
+      if (queueOfUpload[queueIndex].error == null) {
+        queueOfUpload.removeAt(queueIndex);
+      }
+      _stopProgressSyncTimer();
+      _syncProgress();
 
-    if (queueOfUpload[queueIndex].error == null) {
-      queueOfUpload.removeAt(queueIndex);
+      isUploading.value = false;
     }
-    _stopProgressSyncTimer();
-    _syncProgress();
 
-    isUploading.value = false;
-
-    return result;
+    return null;
   }
 
   Future<void> performUploadQueue({
@@ -117,22 +122,23 @@ class AttachmentUploaderController extends GetxController {
       queueOfUpload[idx].isUploading = true;
 
       final task = queueOfUpload[idx];
-      final result = await _rawUploadAttachment(
-        await task.file.readAsBytes(),
-        task.file.path,
-        task.usage,
-        null,
-        onProgress: (value) {
-          queueOfUpload[idx].progress = value;
-          _progressOfUpload = (idx + value) / queueOfUpload.length;
-        },
-        onError: (err) {
-          queueOfUpload[idx].error = err;
-          queueOfUpload[idx].isUploading = false;
-        },
-      );
-      _progressOfUpload = (idx + 1) / queueOfUpload.length;
-      if (result != null) onData(result);
+      try {
+        final result = await _chunkedUploadAttachment(
+          task.file,
+          task.pool,
+          null,
+          onData: (_) {},
+          onProgress: (progress) {
+            queueOfUpload[idx].progress = progress;
+          },
+        );
+        if (result != null) onData(result);
+      } catch (err) {
+        queueOfUpload[idx].error = err;
+        queueOfUpload[idx].isUploading = false;
+      } finally {
+        _progressOfUpload = (idx + 1) / queueOfUpload.length;
+      }
 
       queueOfUpload[idx].isUploading = false;
       queueOfUpload[idx].isCompleted = true;
@@ -145,69 +151,75 @@ class AttachmentUploaderController extends GetxController {
     isUploading.value = false;
   }
 
-  Future<void> uploadAttachmentWithCallback(
-    Uint8List data,
-    String path,
-    String pool,
-    Map<String, dynamic>? metadata,
-    Function(Attachment?) callback,
-  ) async {
-    if (isUploading.value) throw Exception('uploading blocked');
-
-    isUploading.value = true;
-    final result = await _rawUploadAttachment(
-      data,
-      path,
-      pool,
-      metadata,
-      onProgress: (progress) {
-        progressOfUpload.value = progress;
-      },
-    );
-    isUploading.value = false;
-    callback(result);
-  }
-
-  Future<Attachment?> uploadAttachment(
+  Future<Attachment?> uploadAttachmentFromData(
     Uint8List data,
     String path,
     String pool,
     Map<String, dynamic>? metadata,
   ) async {
     if (isUploading.value) throw Exception('uploading blocked');
-
     isUploading.value = true;
-    final result = await _rawUploadAttachment(
-      data,
-      path,
-      pool,
-      metadata,
-      onProgress: (progress) {
-        progressOfUpload.value = progress;
-      },
-    );
-    isUploading.value = false;
-    return result;
-  }
 
-  Future<Attachment?> _rawUploadAttachment(
-      Uint8List data, String path, String pool, Map<String, dynamic>? metadata,
-      {Function(double)? onProgress, Function(dynamic err)? onError}) async {
-    final AttachmentProvider provider = Get.find();
+    final AttachmentProvider attach = Get.find();
+
     try {
-      final result = await provider.createAttachment(
+      final result = await attach.createAttachmentDirectly(
         data,
         path,
         pool,
         metadata,
-        onProgress: onProgress,
       );
       return result;
-    } catch (err) {
-      if (onError != null) {
-        onError(err);
-      }
+    } catch (_) {
       return null;
+    } finally {
+      isUploading.value = false;
     }
   }
+
+  Future<Attachment?> _chunkedUploadAttachment(
+    XFile file,
+    String pool,
+    Map<String, dynamic>? metadata, {
+    required Function(AttachmentPlaceholder) onData,
+    required Function(double) onProgress,
+  }) async {
+    final AttachmentProvider attach = Get.find();
+
+    final holder = await attach.createAttachmentMultipartPlaceholder(
+      await file.length(),
+      file.path,
+      pool,
+      metadata,
+    );
+    onData(holder);
+
+    onProgress(0);
+
+    final filename = basename(file.path);
+    final chunks = holder.meta.fileChunks ?? {};
+    var currentTask = 0;
+    for (final entry in chunks.entries) {
+      final beginCursor = entry.value * holder.chunkSize;
+      final endCursor = (entry.value + 1) * holder.chunkSize;
+      final data = Uint8List.fromList(await file
+          .openRead(beginCursor, endCursor)
+          .expand((chunk) => chunk)
+          .toList());
+
+      final out = await attach.uploadAttachmentMultipartChunk(
+        data,
+        filename,
+        holder.meta.rid,
+        entry.key,
+      );
+      holder.meta = out;
+
+      currentTask++;
+      onProgress(currentTask / chunks.length);
+      onData(holder);
+    }
+
+    return holder.meta;
+  }
 }
diff --git a/lib/providers/content/attachment.dart b/lib/providers/content/attachment.dart
index 81ff5af..20459c4 100644
--- a/lib/providers/content/attachment.dart
+++ b/lib/providers/content/attachment.dart
@@ -7,7 +7,6 @@ import 'package:solian/models/attachment.dart';
 import 'package:solian/models/pagination.dart';
 import 'package:solian/providers/auth.dart';
 import 'package:solian/services.dart';
-import 'package:dio/dio.dart' as dio;
 
 class AttachmentProvider extends GetConnect {
   static Map<String, String> mimetypeOverrides = {
@@ -83,16 +82,21 @@ class AttachmentProvider extends GetConnect {
     return null;
   }
 
-  Future<Attachment> createAttachment(
-      Uint8List data, String path, String pool, Map<String, dynamic>? metadata,
-      {Function(double)? onProgress}) async {
+  Future<Attachment> createAttachmentDirectly(
+    Uint8List data,
+    String path,
+    String pool,
+    Map<String, dynamic>? metadata,
+  ) async {
     final AuthProvider auth = Get.find();
     if (auth.isAuthorized.isFalse) throw Exception('unauthorized');
 
-    await auth.ensureCredentials();
+    final client = auth.configureClient(
+      'uc',
+      timeout: const Duration(minutes: 3),
+    );
 
-    final filePayload =
-        dio.MultipartFile.fromBytes(data, filename: basename(path));
+    final filePayload = MultipartFile(data, filename: basename(path));
     final fileAlt = basename(path).contains('.')
         ? basename(path).substring(0, basename(path).lastIndexOf('.'))
         : basename(path);
@@ -105,30 +109,82 @@ class AttachmentProvider extends GetConnect {
     if (mimetypeOverrides.keys.contains(fileExt)) {
       mimetypeOverride = mimetypeOverrides[fileExt];
     }
-    final payload = dio.FormData.fromMap({
+    final payload = FormData({
       'alt': fileAlt,
       'file': filePayload,
       'pool': pool,
       if (mimetypeOverride != null) 'mimetype': mimetypeOverride,
       'metadata': jsonEncode(metadata),
     });
-    final resp = await dio.Dio(
-      dio.BaseOptions(
-        baseUrl: ServiceFinder.buildUrl('files', null),
-        headers: {'Authorization': 'Bearer ${auth.credentials!.accessToken}'},
-      ),
-    ).post(
-      '/attachments',
-      data: payload,
-      onSendProgress: (count, total) {
-        if (onProgress != null) onProgress(count / total);
-      },
-    );
+    final resp = await client.post('/attachments', payload);
     if (resp.statusCode != 200) {
-      throw Exception(resp.data);
+      throw Exception(resp.bodyString);
     }
 
-    return Attachment.fromJson(resp.data);
+    return Attachment.fromJson(resp.body);
+  }
+
+  Future<AttachmentPlaceholder> createAttachmentMultipartPlaceholder(
+    int size,
+    String path,
+    String pool,
+    Map<String, dynamic>? metadata,
+  ) async {
+    final AuthProvider auth = Get.find();
+    if (auth.isAuthorized.isFalse) throw Exception('unauthorized');
+
+    final client = auth.configureClient('uc');
+
+    final fileAlt = basename(path).contains('.')
+        ? basename(path).substring(0, basename(path).lastIndexOf('.'))
+        : basename(path);
+    final fileExt = basename(path)
+        .substring(basename(path).lastIndexOf('.') + 1)
+        .toLowerCase();
+
+    // Override for some files cannot be detected mimetype by server-side
+    String? mimetypeOverride;
+    if (mimetypeOverrides.keys.contains(fileExt)) {
+      mimetypeOverride = mimetypeOverrides[fileExt];
+    }
+    final resp = await client.post('/attachments/multipart', {
+      'alt': fileAlt,
+      'name': basename(path),
+      'size': size,
+      'pool': pool,
+      if (mimetypeOverride != null) 'mimetype': mimetypeOverride,
+      'metadata': metadata,
+    });
+    if (resp.statusCode != 200) {
+      throw Exception(resp.bodyString);
+    }
+
+    return AttachmentPlaceholder.fromJson(resp.body);
+  }
+
+  Future<Attachment> uploadAttachmentMultipartChunk(
+    Uint8List data,
+    String name,
+    String rid,
+    String cid,
+  ) async {
+    final AuthProvider auth = Get.find();
+    if (auth.isAuthorized.isFalse) throw Exception('unauthorized');
+
+    final client = auth.configureClient(
+      'uc',
+      timeout: const Duration(minutes: 3),
+    );
+
+    final payload = FormData({
+      'file': MultipartFile(data, filename: name),
+    });
+    final resp = await client.post('/attachments/multipart/$rid/$cid', payload);
+    if (resp.statusCode != 200) {
+      throw Exception(resp.bodyString);
+    }
+
+    return Attachment.fromJson(resp.body);
   }
 
   Future<Response> updateAttachment(
diff --git a/lib/screens/account/personalize.dart b/lib/screens/account/personalize.dart
index 34418ad..ec02c92 100644
--- a/lib/screens/account/personalize.dart
+++ b/lib/screens/account/personalize.dart
@@ -113,7 +113,7 @@ class _PersonalizeScreenState extends State<PersonalizeScreen> {
 
     Attachment? attachResult;
     try {
-      attachResult = await provider.createAttachment(
+      attachResult = await provider.createAttachmentDirectly(
         await file.readAsBytes(),
         file.path,
         'avatar',
diff --git a/lib/widgets/attachments/attachment_editor.dart b/lib/widgets/attachments/attachment_editor.dart
index 098a1df..15f859e 100644
--- a/lib/widgets/attachments/attachment_editor.dart
+++ b/lib/widgets/attachments/attachment_editor.dart
@@ -72,8 +72,8 @@ class _AttachmentEditorPopupState extends State<AttachmentEditorPopup> {
       if (medias.isEmpty) return;
 
       _enqueueTaskBatch(medias.map((x) {
-        final file = File(x.path);
-        return AttachmentUploadTask(file: file, usage: widget.pool);
+        final file = XFile(x.path);
+        return AttachmentUploadTask(file: file, pool: widget.pool);
       }));
     } else {
       final media = await _imagePicker.pickMedia(
@@ -83,7 +83,7 @@ class _AttachmentEditorPopupState extends State<AttachmentEditorPopup> {
       if (media == null) return;
 
       _enqueueTask(
-        AttachmentUploadTask(file: File(media.path), usage: widget.pool),
+        AttachmentUploadTask(file: XFile(media.path), pool: widget.pool),
       );
     }
   }
@@ -95,9 +95,8 @@ class _AttachmentEditorPopupState extends State<AttachmentEditorPopup> {
     final media = await _imagePicker.pickVideo(source: ImageSource.gallery);
     if (media == null) return;
 
-    final file = File(media.path);
     _enqueueTask(
-      AttachmentUploadTask(file: file, usage: widget.pool),
+      AttachmentUploadTask(file: XFile(media.path), pool: widget.pool),
     );
   }
 
@@ -113,7 +112,7 @@ class _AttachmentEditorPopupState extends State<AttachmentEditorPopup> {
     List<File> files = result.paths.map((path) => File(path!)).toList();
 
     _enqueueTaskBatch(files.map((x) {
-      return AttachmentUploadTask(file: x, usage: widget.pool);
+      return AttachmentUploadTask(file: XFile(x.path), pool: widget.pool);
     }));
   }
 
@@ -129,9 +128,8 @@ class _AttachmentEditorPopupState extends State<AttachmentEditorPopup> {
     }
     if (media == null) return;
 
-    final file = File(media.path);
     _enqueueTask(
-      AttachmentUploadTask(file: file, usage: widget.pool),
+      AttachmentUploadTask(file: XFile(media.path), pool: widget.pool),
     );
   }
 
@@ -197,20 +195,16 @@ class _AttachmentEditorPopupState extends State<AttachmentEditorPopup> {
 
     if (_uploadController.isUploading.value) return;
 
-    _uploadController.uploadAttachmentWithCallback(
-      data,
-      'Pasted Image',
-      widget.pool,
-      null,
-      (item) {
-        if (item == null) return;
-        widget.onAdd(item.rid);
-        if (mounted) {
-          setState(() => _attachments.add(item));
-          if (widget.singleMode) Navigator.pop(context);
-        }
-      },
-    );
+    _uploadController
+        .uploadAttachmentFromData(data, 'Pasted Image', widget.pool, null)
+        .then((item) {
+      if (item == null) return;
+      widget.onAdd(item.rid);
+      if (mounted) {
+        setState(() => _attachments.add(item));
+        if (widget.singleMode) Navigator.pop(context);
+      }
+    });
   }
 
   String _formatBytes(int bytes, {int decimals = 2}) {
@@ -304,7 +298,7 @@ class _AttachmentEditorPopupState extends State<AttachmentEditorPopup> {
       ],
     );
     if (croppedFile == null) return;
-    _uploadController.queueOfUpload[queueIndex].file = File(croppedFile.path);
+    _uploadController.queueOfUpload[queueIndex].file = XFile(croppedFile.path);
     _uploadController.queueOfUpload.refresh();
   }
 
@@ -581,8 +575,8 @@ class _AttachmentEditorPopupState extends State<AttachmentEditorPopup> {
         onDragDone: (detail) async {
           if (_uploadController.isUploading.value) return;
           _enqueueTaskBatch(detail.files.map((x) {
-            final file = File(x.path);
-            return AttachmentUploadTask(file: file, usage: widget.pool);
+            final file = XFile(x.path);
+            return AttachmentUploadTask(file: file, pool: widget.pool);
           }));
         },
         child: Column(
diff --git a/pubspec.lock b/pubspec.lock
index f09fb4a..2b0aec9 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -263,7 +263,7 @@ packages:
     source: hosted
     version: "3.1.1"
   cross_file:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: cross_file
       sha256: "7caf6a750a0c04effbb52a676dce9a4a592e10ad35c34d6d2d0e4811160d5670"
diff --git a/pubspec.yaml b/pubspec.yaml
index d4b1999..82fa37c 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -72,6 +72,7 @@ dependencies:
   media_kit_video: ^1.2.4
   media_kit_libs_video: ^1.0.4
   flutter_svg: ^2.0.10+1
+  cross_file: ^0.3.4+2
 
 dev_dependencies:
   flutter_test: