diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5364f3c0..f0877048 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,15 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [5.0.1-mki.1]
+### Fixed
+- Column widths & row heights parsing (cols/rows width/ht + defaults).
+- More robust cell parsing: formula-first (<f>), safe sharedStrings lookup, full inlineStr handling, and bounds checks for numFmtId and style indices.
+
+### Added
+- Added toJson / fromJson + toString = jsonEncode(toJson()) methods
+- Added generateXFile wich generate a XFile with mimeType
+
 ## [5.0.0]
 - Update packages to latest versions
 - Migrate from `dart:html` to `package:web`
diff --git a/lib/excel.dart b/lib/excel.dart
index 170157e2..79202297 100644
--- a/lib/excel.dart
+++ b/lib/excel.dart
@@ -4,6 +4,7 @@ import 'dart:convert';
 import 'dart:math';
 import 'package:archive/archive.dart';
 import 'package:collection/collection.dart';
+import 'package:cross_file/cross_file.dart';
 import 'package:equatable/equatable.dart';
 import 'package:xml/xml.dart';
 import 'src/web_helper/client_save_excel.dart'
diff --git a/lib/src/excel.dart b/lib/src/excel.dart
index 41d77263..8547c10a 100644
--- a/lib/src/excel.dart
+++ b/lib/src/excel.dart
@@ -79,7 +79,176 @@ class Excel {
   }
 
   factory Excel.decodeBuffer(InputStream input) {
-    return _newExcel(ZipDecoder().decodeStream(input));
+    return _newExcel(ZipDecoder().decodeStream(input, verify: true));
+  }
+
+  factory Excel.fromJson(Map<String, dynamic> json) {
+    final excel = Excel.createExcel();
+
+    final defaultName = excel.sheets.keys.first;
+    final firstTarget = json.keys.first;
+    if (defaultName != firstTarget) {
+      excel.rename(defaultName, firstTarget);
+    }
+
+    if (json.isEmpty) return excel;
+
+    json.forEach((sheetName, rawRows) {
+      if (rawRows is! List) {
+        excel._availSheet(sheetName);
+        return;
+      }
+
+      final rows =
+          rawRows.whereType<Map<String, dynamic>>().toList(growable: false);
+
+      excel._availSheet(sheetName);
+
+      if (rows.isEmpty) return;
+
+      final headers = rows.first.keys.toList(growable: false);
+
+      excel.appendRow(
+        sheetName,
+        [for (final h in headers) TextCellValue(h)],
+      );
+
+      for (final record in rows) {
+        excel.appendRow(
+          sheetName,
+          [for (final h in headers) _toCellValue(record[h])],
+        );
+      }
+    });
+
+    if (excel.sheets.isNotEmpty) {
+      excel.setDefaultSheet(excel.sheets.keys.first);
+    }
+
+    return excel;
+  }
+
+  static CellValue? _toCellValue(dynamic v) {
+    if (v == null) return null;
+
+    if (v is CellValue) return v;
+
+    if (v is bool) return BoolCellValue(v);
+
+    if (v is num) {
+      final isInt = v == v.truncate();
+      return isInt ? IntCellValue(v.toInt()) : DoubleCellValue(v.toDouble());
+    }
+
+    if (v is String) {
+      final s = v.trim();
+
+      if (s.startsWith('=')) return FormulaCellValue(s);
+
+      final b = bool.tryParse(s);
+      if (b != null) return BoolCellValue(b);
+
+      final i = int.tryParse(s);
+      if (i != null) return IntCellValue(i);
+      final d = double.tryParse(s);
+      if (d != null) return DoubleCellValue(d);
+
+      final timeRe = RegExp(r'^\d{2}:\d{2}:\d{2}(?:\.\d+)?$');
+      if (timeRe.hasMatch(s)) {
+        final parts = s.split(':');
+        final secParts = parts[2].split('.');
+        final h = int.parse(parts[0]);
+        final m = int.parse(parts[1]);
+        final sec = int.parse(secParts[0]);
+        final ms = secParts.length > 1
+            ? int.parse(secParts[1].padRight(3, '0').substring(0, 3))
+            : 0;
+        return TimeCellValue(hour: h, minute: m, second: sec, millisecond: ms);
+      }
+
+      final dt = DateTime.tryParse(s);
+      if (dt != null) {
+        final u = dt.toUtc();
+        final isMidnight = u.hour == 0 &&
+            u.minute == 0 &&
+            u.second == 0 &&
+            u.millisecond == 0 &&
+            u.microsecond == 0;
+        if (isMidnight) {
+          return DateCellValue(year: u.year, month: u.month, day: u.day);
+        } else {
+          return DateTimeCellValue(
+            year: u.year,
+            month: u.month,
+            day: u.day,
+            hour: u.hour,
+            minute: u.minute,
+            second: u.second,
+            millisecond: u.millisecond,
+            microsecond: u.microsecond,
+          );
+        }
+      }
+
+      return TextCellValue(s);
+    }
+
+    return TextCellValue(v.toString());
+  }
+
+  Map<String, dynamic> toJson() {
+    int index = 0;
+    Map<String, dynamic> json = {};
+
+    for (final sheet in this.sheets.keys) {
+      List<Data?> keys = [];
+      json.addAll({sheet: []});
+      final rows = sheets[sheet]?.rows ?? [];
+
+      for (final row in rows) {
+        try {
+          if (index == 0) {
+            keys = row;
+            index++;
+          } else {
+            Map<String, dynamic> temp = {};
+            int index = 0;
+            String tk = '';
+
+            for (final key in keys) {
+              if (key != null && key.value != null) {
+                tk = key.value.toString();
+
+                temp[tk] = switch (row[index]?.value) {
+                  (final v) when v is IntCellValue => v.value,
+                  (final v) when v is DoubleCellValue => v.value,
+                  (final v) when v is BoolCellValue => v.value,
+                  (final v) when v is FormulaCellValue => v.formula,
+                  (final v) when v is TextCellValue => v.value.toString(),
+                  (final v) when v is TimeCellValue => v.toString(),
+                  (final v) when v is DateCellValue => v.toString(),
+                  (final v) when v is DateTimeCellValue => v.toString(),
+                  _ => null,
+                };
+
+                index++;
+              }
+            }
+
+            json[sheet].add(temp);
+          }
+        } catch (e) {
+          rethrow;
+        }
+      }
+      index = 0;
+    }
+    return json;
+  }
+
+  @override
+  String toString() {
+    return jsonEncode(toJson());
   }
 
   ///
@@ -331,11 +500,16 @@ class Excel {
   ///
   ///```
   List<int>? save({String fileName = 'FlutterExcel.xlsx'}) {
-    Save s = Save._(this, parser);
-    var onValue = s._save();
+    var onValue = encode();
     return helper.SavingHelper.saveFile(onValue, fileName);
   }
 
+  /// Generate XFile with mimeType and path = fileName.
+  XFile? generateXFile({String fileName = 'FlutterExcel.xlsx'}) {
+    var onValue = encode();
+    return helper.SavingHelper.generateXFile(onValue, fileName);
+  }
+
   ///
   ///returns the name of the `defaultSheet` (the sheet which opens firstly when xlsx file is opened in `excel based software`).
   ///
diff --git a/lib/src/parser/parse.dart b/lib/src/parser/parse.dart
index b6a71735..50b733fa 100644
--- a/lib/src/parser/parse.dart
+++ b/lib/src/parser/parse.dart
@@ -539,6 +539,13 @@ class Parser {
     var content = XmlDocument.parse(utf8.decode(file.content));
     var worksheet = content.findElements('worksheet').first;
 
+    var cols = worksheet.findAllElements('cols').toList();
+    if (cols.isNotEmpty) {
+      var colsNode = cols.first;
+      var columns = _findColumns(colsNode);
+      _parseColumns(columns, sheetObject, name);
+    }
+
     ///
     /// check for right to left view
     ///
@@ -548,11 +555,11 @@ class Parser {
       var rtl = sheetViewNode.getAttribute('rightToLeft');
       sheetObject.isRTL = rtl != null && rtl == '1';
     }
+
     var sheet = worksheet.findElements('sheetData').first;
 
-    _findRows(sheet).forEach((child) {
-      _parseRow(child, sheetObject, name);
-    });
+    var rows = _findRows(sheet);
+    _parseRows(rows, sheetObject, name);
 
     _parseHeaderFooter(worksheet, sheetObject);
     _parseColWidthsRowHeights(worksheet, sheetObject);
@@ -565,99 +572,117 @@ class Parser {
     _normalizeTable(sheetObject);
   }
 
-  _parseRow(XmlElement node, Sheet sheetObject, String name) {
-    var rowIndex = (_getRowNumber(node) ?? -1) - 1;
-    if (rowIndex < 0) {
-      return;
+  _parseColumns(Iterable<XmlElement> columns, Sheet sheetObject, String name) {
+    for (int i = 0; i < columns.length; i++) {
+      var autofit = _getColumnAutofit(columns.elementAt(i));
+      _excel.sheets[name]!._columnAutoFit
+          .update(i, (value) => autofit, ifAbsent: () => autofit);
+
+      var width = _getColumnWidth(columns.elementAt(i));
+      if (width != null) {
+        _excel.sheets[name]!._columnWidths
+            .update(i, (value) => width, ifAbsent: () => width);
+      }
     }
+  }
+
+  _parseRows(Iterable<XmlElement> rows, Sheet sheetObject, String name) {
+    rows.forEach((row) {
+      var rowIndex = (_getRowNumber(row) ?? -1) - 1;
+      if (rowIndex < 0) {
+        return;
+      }
+
+      var height = _getRowHeight(row);
+
+      if (height != null) {
+        _excel.sheets[name]!._rowHeights
+            .update(rowIndex, (value) => height, ifAbsent: () => height);
+      }
 
-    _findCells(node).forEach((child) {
-      _parseCell(child, sheetObject, rowIndex, name);
+      var cells = _findCells(row);
+      cells.forEach((cell) => _parseCell(cell, sheetObject, rowIndex, name));
     });
   }
 
   void _parseCell(
       XmlElement node, Sheet sheetObject, int rowIndex, String name) {
-    int? columnIndex = _getCellNumber(node);
-    if (columnIndex == null) {
-      return;
-    }
-
-    var s1 = node.getAttribute('s');
-    int s = 0;
-    if (s1 != null) {
-      try {
-        s = int.parse(s1.toString());
-      } catch (_) {}
+    final columnIndex = _getCellNumber(node);
+    if (columnIndex == null) return;
 
-      String rC = node.getAttribute('r').toString();
+    // style index
+    final styleAttr = node.getAttribute('s');
+    final styleIndex = int.tryParse(styleAttr ?? '') ?? 0;
 
-      if (_excel._cellStyleReferenced[name] == null) {
-        _excel._cellStyleReferenced[name] = {rC: s};
-      } else {
-        _excel._cellStyleReferenced[name]![rC] = s;
-      }
+    // style by rc if possible
+    final rc = node.getAttribute('r');
+    if (rc != null) {
+      (_excel._cellStyleReferenced[name] ??= {})[rc] = styleIndex;
     }
 
+    // formula except t
+    final fNode = node.findElements('f').firstOrNull;
+
     CellValue? value;
-    String? type = node.getAttribute('t');
-
-    switch (type) {
-      // sharedString
-      case 's':
-        final sharedString = _excel._sharedStrings
-            .value(int.parse(_parseValue(node.findElements('v').first)));
-        value = TextCellValue.span(sharedString!.textSpan);
-        break;
-      // boolean
-      case 'b':
-        value = BoolCellValue(_parseValue(node.findElements('v').first) == '1');
-        break;
-      // error
-      case 'e':
-      // formula
-      case 'str':
-        value = FormulaCellValue(_parseValue(node.findElements('v').first));
-        break;
-      // inline string
-      case 'inlineStr':
-        // <c r='B2' t='inlineStr'>
-        // <is><t>Dartonico</t></is>
-        // </c>
-        value = TextCellValue(_parseValue(node.findAllElements('t').first));
-        break;
-      // number
-      case 'n':
-      default:
-        var formulaNode = node.findElements('f');
-        if (formulaNode.isNotEmpty) {
-          value = FormulaCellValue(_parseValue(formulaNode.first).toString());
-        } else {
+    if (fNode != null) {
+      value = FormulaCellValue(_parseValue(fNode));
+    } else {
+      final t = node.getAttribute('t');
+      switch (t) {
+        // sharedString
+        case 's':
           final vNode = node.findElements('v').firstOrNull;
-          if (vNode == null) {
-            value = null;
-          } else if (s1 != null) {
-            final v = _parseValue(vNode);
-            var numFmtId = _excel._numFmtIds[s];
-            final numFormat = _excel._numFormats.getByNumFmtId(numFmtId);
-            if (numFormat == null) {
-              assert(
-                  false, 'found no number format spec for numFmtId $numFmtId');
-              value = NumFormat.defaultNumeric.read(v);
-            } else {
-              value = numFormat.read(v);
-            }
+          if (vNode != null) {
+            final idx = int.tryParse(_parseValue(vNode));
+            final sh = idx != null ? _excel._sharedStrings.value(idx) : null;
+            if (sh != null) value = TextCellValue.span(sh.textSpan);
+          }
+          break;
+        // boolean
+        case 'b':
+          final v = node.findElements('v').firstOrNull;
+          value = BoolCellValue(v != null && _parseValue(v) == '1');
+          break;
+        // error
+        case 'e':
+          final v = node.findElements('v').firstOrNull;
+          value = v != null ? TextCellValue(_parseValue(v)) : null;
+          break;
+        // formula
+        case 'str':
+          final v = node.findElements('v').firstOrNull;
+          value = v != null ? FormulaCellValue(_parseValue(v)) : null;
+          break;
+        // inline string
+        case 'inlineStr':
+          final text = node.findAllElements('t').map(_parseValue).join();
+          value = TextCellValue(text);
+          break;
+        // numeric
+        default:
+          final vNode = node.findElements('v').firstOrNull;
+          if (vNode != null) {
+            final raw = _parseValue(vNode);
+            final fmtId =
+                (styleIndex >= 0 && styleIndex < _excel._numFmtIds.length)
+                    ? _excel._numFmtIds[styleIndex]
+                    : null;
+            final fmt =
+                fmtId != null ? _excel._numFormats.getByNumFmtId(fmtId) : null;
+            value = (fmt ?? NumFormat.defaultNumeric).read(raw);
           } else {
-            final v = _parseValue(vNode);
-            value = NumFormat.defaultNumeric.read(v);
+            value = null;
           }
-        }
+          break;
+      }
     }
 
     sheetObject.updateCell(
       CellIndex.indexByColumnRow(columnIndex: columnIndex, rowIndex: rowIndex),
       value,
-      cellStyle: _excel._cellStyleList[s],
+      cellStyle: (styleIndex >= 0 && styleIndex < _excel._cellStyleList.length)
+          ? _excel._cellStyleList[styleIndex]
+          : null,
     );
   }
 
diff --git a/lib/src/save/save_file.dart b/lib/src/save/save_file.dart
index ee4ab490..109509a4 100644
--- a/lib/src/save/save_file.dart
+++ b/lib/src/save/save_file.dart
@@ -6,6 +6,7 @@ class Save {
   final List<CellStyle> _innerCellStyle = [];
   final Parser parser;
 
+
   Save._(this._excel, this.parser);
 
   void _addNewColumn(XmlElement columns, int min, int max, double width) {
@@ -543,6 +544,7 @@ class Save {
       _processStylesFile();
     }
     _setSheetElements();
+
     if (_excel._defaultSheet != null) {
       _setDefaultSheet(_excel._defaultSheet);
     }
@@ -635,6 +637,7 @@ class Save {
       if (sheetObject._sheetData[rowIndex] == null) {
         continue;
       }
+
       var foundRow = _createNewRow(
           _excel._sheets[sheetName]! as XmlElement, rowIndex, height);
       for (var columnIndex = 0;
diff --git a/lib/src/sheet/data_model.dart b/lib/src/sheet/data_model.dart
index 3b2caa68..947aa113 100644
--- a/lib/src/sheet/data_model.dart
+++ b/lib/src/sheet/data_model.dart
@@ -92,9 +92,9 @@ class Data extends Equatable {
   }
 
   /// sets the user defined CellStyle in this current cell
-  set cellStyle(CellStyle? _) {
+  set cellStyle(CellStyle? cellStyle) {
     _sheet._excel._styleChanges = true;
-    _cellStyle = _;
+    _cellStyle = cellStyle;
   }
 
   @override
diff --git a/lib/src/sheet/sheet.dart b/lib/src/sheet/sheet.dart
index c1a6906f..fba2313c 100644
--- a/lib/src/sheet/sheet.dart
+++ b/lib/src/sheet/sheet.dart
@@ -73,6 +73,7 @@ class Sheet {
     }
 
     /// copy the data objects into a temp folder and then while putting it into `_sheetData` change the data objects references.
+
     if (sh != null) {
       _sheetData = <int, Map<int, Data>>{};
       Map<int, Map<int, Data>> temp = Map<int, Map<int, Data>>.from(sh);
diff --git a/lib/src/utilities/utility.dart b/lib/src/utilities/utility.dart
index 36900be4..1c09a43a 100644
--- a/lib/src/utilities/utility.dart
+++ b/lib/src/utilities/utility.dart
@@ -41,6 +41,10 @@ Iterable<XmlElement> _findRows(XmlElement table) {
   return table.findElements('row');
 }
 
+Iterable<XmlElement> _findColumns(XmlElement table) {
+  return table.findElements('col');
+}
+
 Iterable<XmlElement> _findCells(XmlElement row) {
   return row.findElements('c');
 }
@@ -57,6 +61,18 @@ int? _getRowNumber(XmlElement row) {
   return int.tryParse(row.getAttribute('r').toString());
 }
 
+double? _getRowHeight(XmlElement row) {
+  return double.tryParse(row.getAttribute('ht').toString());
+}
+
+double? _getColumnWidth(XmlElement column) {
+  return double.tryParse(column.getAttribute('width').toString());
+}
+
+bool _getColumnAutofit(XmlElement column) {
+  return int.tryParse(column.getAttribute('bestFit').toString()) == 1 ? true : false;
+}
+
 int _checkPosition(List<CellStyle> list, CellStyle cellStyle) {
   return list.indexOf(cellStyle);
 }
diff --git a/lib/src/web_helper/client_save_excel.dart b/lib/src/web_helper/client_save_excel.dart
index c7818b89..c1ac5706 100644
--- a/lib/src/web_helper/client_save_excel.dart
+++ b/lib/src/web_helper/client_save_excel.dart
@@ -1,6 +1,24 @@
+import 'dart:typed_data';
+
+import 'package:cross_file/cross_file.dart';
+
 class SavingHelper {
 // A wrapper to save the excel file in client
   static List<int>? saveFile(List<int>? val, String fileName) {
     return val;
   }
+
+  static XFile? generateXFile(List<int>? val, String fileName) {
+    if (val == null) return null;
+    final bytes = Uint8List.fromList(val);
+    return XFile.fromData(
+      bytes,
+      name: fileName,
+      length: bytes.length,
+      lastModified: DateTime.now(),
+      mimeType:
+          'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+      path: fileName,
+    );
+  }
 }
diff --git a/lib/src/web_helper/web_save_excel_browser.dart b/lib/src/web_helper/web_save_excel_browser.dart
index 861afbbd..2ae1fda0 100644
--- a/lib/src/web_helper/web_save_excel_browser.dart
+++ b/lib/src/web_helper/web_save_excel_browser.dart
@@ -1,6 +1,7 @@
 import 'dart:js_interop';
 import 'dart:typed_data';
 
+import 'package:cross_file/cross_file.dart';
 import 'package:web/web.dart';
 
 // A wrapper to save the excel file in browser
@@ -26,4 +27,18 @@ class SavingHelper {
     URL.revokeObjectURL(url);
     return val;
   }
+
+  static XFile? generateXFile(List<int>? val, String fileName) {
+    if (val == null) return null;
+    final bytes = Uint8List.fromList(val);
+    return XFile.fromData(
+      bytes,
+      name: fileName,
+      length: bytes.length,
+      lastModified: DateTime.now(),
+      mimeType:
+          'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+      path: fileName,
+    );
+  }
 }
diff --git a/pubspec.yaml b/pubspec.yaml
index c2d3c57f..e46db204 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: excel
 description: A flutter and dart library for reading, creating, editing and updating excel sheets with compatible both on client and server side.
-version: 5.0.0
+version: 5.0.1-mki.1
 homepage: https://github.com/justkawal/excel
 topics:
   - excel
@@ -18,7 +18,7 @@ dependencies:
   xml: ">=5.0.0 <7.0.0"
   collection: ^1.15.0
   equatable: ^2.0.0
+  cross_file: ^0.3.4+2
 
 dev_dependencies:
-  test: ^1.23.0
-  lints: ^5.1.1
+  test: ^1.26.3
diff --git a/test/excel_test.dart b/test/excel_test.dart
index 2eff9686..4356a4d5 100644
--- a/test/excel_test.dart
+++ b/test/excel_test.dart
@@ -1101,4 +1101,200 @@ void main() {
       reason: 'Decoding the file should not throw any exception',
     );
   });
+
+  /// mki
+  test('JSON view stable across encode/decode', () {
+    final src = {
+      'S': [
+        {
+          'X': 1,
+          'Y': 2.5,
+          'Z': '=X1+Y1',
+          'T': '08:00:00',
+          'D': '2024-01-01T00:00:00.000Z'
+        },
+        {
+          'X': 3,
+          'Y': 4.5,
+          'Z': '=X2+Y2',
+          'T': '12:34:56',
+          'D': '2024-01-02T10:11:12.000Z'
+        },
+      ],
+    };
+
+    final excel = Excel.fromJson(src);
+    final bytes = excel.encode()!;
+    final excel2 = Excel.decodeBytes(bytes);
+    final out = excel2.toJson();
+
+    expect(out, equals(src));
+  });
+
+  test('toJson/fromJson round-trip', () {
+    final file = './test/test_resources/example.xlsx';
+    final bytes = File(file).readAsBytesSync();
+    final excel = Excel.decodeBytes(bytes);
+
+    final out = excel.toJson();
+    final excel2 = Excel.fromJson(out);
+
+    final out2 = excel2.toJson();
+
+    expect(out, equals(out2));
+  });
+
+  test('fromJson string coercion & formula', () {
+    final ex = Excel.fromJson({
+      'S': [
+        {'B': 'true', 'I': '42', 'F': '3.14', 'Z': '=A1+B1'}
+      ]
+    });
+    final r = ex['S'].rows[1];
+    expect(r[0]?.value, BoolCellValue(true));
+    expect(r[1]?.value, IntCellValue(42));
+    expect(r[2]?.value, DoubleCellValue(3.14));
+    expect(r[3]?.value, const FormulaCellValue('=A1+B1'));
+  });
+
+  test('generateXFile returns non-empty XFile with correct name', () async {
+    final file = './test/test_resources/example.xlsx';
+    final bytes = File(file).readAsBytesSync();
+    final excel = Excel.decodeBytes(bytes);
+
+    final xf = excel.generateXFile(fileName: 'test.xlsx')!;
+    expect(xf.name, 'test.xlsx');
+    expect(xf.mimeType,
+        'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
+  });
+
+  test('generateXFile uses provided bytes', () async {
+    final ex = Excel.createExcel();
+    final bytes = ex.encode()!;
+    final xf = ex.generateXFile(fileName: 'a.xlsx')!;
+    expect(await xf.length(), bytes.length);
+  });
+
+  test('formula-first parsing', () {
+    final excel = Excel.createExcel();
+    final sheet = excel['Sheet1'];
+    final cell = sheet.cell(CellIndex.indexByString('B2'));
+    cell.setFormula('=SUM(1,2)');
+
+    final bytes = excel.encode()!;
+    final excel2 = Excel.decodeBytes(bytes);
+    final v = excel2['Sheet1'].cell(CellIndex.indexByString('B2')).value;
+
+    expect(v, equals(const FormulaCellValue('=SUM(1,2)')));
+  });
+
+  group('t="inlineStr"', () {
+    List<int> _rewriteZipEntry(
+        List<int> zipBytes, String path, String Function(String) transform) {
+      final arc = ZipDecoder().decodeBytes(zipBytes);
+      final out = Archive();
+      for (final f in arc.files) {
+        if (f.name == path) {
+          final xml = utf8.decode(f.content);
+          final updated = transform(xml);
+          final bytes = utf8.encode(updated);
+          out.addFile(ArchiveFile(path, bytes.length, bytes));
+        } else {
+          out.addFile(ArchiveFile.noCompress(f.name, f.size, f.content));
+        }
+      }
+      return ZipEncoder().encode(out)!;
+    }
+
+    List<int> _patchInlineStr(List<int> bytes, String cellRef,
+        {String? plain, String? xmlSpacePreserve, List<String>? runs}) {
+      return _rewriteZipEntry(
+        bytes,
+        'xl/worksheets/sheet1.xml',
+        (xml) {
+          final doc = XmlDocument.parse(xml);
+          final c = doc.findAllElements('c').firstWhere(
+                (e) => e.getAttribute('r') == cellRef,
+                orElse: () => throw StateError('$cellRef not found'),
+              );
+
+          c.children.clear();
+          c.attributes
+              .removeWhere((a) => a.name.local == 't' || a.name.local == 's');
+          c.setAttribute('t', 'inlineStr');
+
+          final isNode = XmlElement(XmlName('is'));
+
+          if (plain != null) {
+            isNode.children.add(
+              XmlElement(XmlName('t'), [], [XmlText(plain)]),
+            );
+          } else if (xmlSpacePreserve != null) {
+            isNode.children.add(
+              XmlElement(
+                XmlName('t'),
+                [XmlAttribute(XmlName('xml:space'), 'preserve')],
+                [XmlText(xmlSpacePreserve)],
+              ),
+            );
+          } else if (runs != null && runs.isNotEmpty) {
+            for (final text in runs) {
+              isNode.children.add(
+                XmlElement(XmlName('r'), [], [
+                  XmlElement(XmlName('t'), [], [XmlText(text)]),
+                ]),
+              );
+            }
+          } else {
+            throw ArgumentError('Provide plain or xmlSpacePreserve or runs');
+          }
+
+          c.children.add(isNode);
+          return doc.toXmlString();
+        },
+      );
+    }
+
+    test('plain inlineStr', () {
+      final excel = Excel.createExcel();
+      excel['Sheet1']
+          .appendRow([TextCellValue('X'), TextCellValue('Y')]); // A1,B1
+      final bytes = excel.encode()!;
+
+      final patched = _patchInlineStr(bytes, 'B1', plain: 'HelloInline');
+      final excel2 = Excel.decodeBytes(patched);
+
+      expect(
+        excel2['Sheet1'].cell(CellIndex.indexByString('B1')).value,
+        TextCellValue('HelloInline'),
+      );
+    });
+
+    test('inlineStr xml:space="preserve"', () {
+      final excel = Excel.createExcel();
+      excel['Sheet1']
+          .appendRow([TextCellValue('X'), TextCellValue('Y')]); // A1,B1
+      final bytes = excel.encode()!;
+
+      final s = '  Hello  inline \n with spaces  ';
+      final patched = _patchInlineStr(bytes, 'B1', xmlSpacePreserve: s);
+      final excel2 = Excel.decodeBytes(patched);
+      final v = excel2['Sheet1'].cell(CellIndex.indexByString('B1')).value;
+
+      expect(v, TextCellValue(s));
+    });
+
+    test('inlineStr rich text (multiple <r>)', () {
+      final excel = Excel.createExcel();
+      excel['Sheet1']
+          .appendRow([TextCellValue('X'), TextCellValue('Y')]); // A1,B1
+      final bytes = excel.encode()!;
+
+      final pieces = ['Hello', ' ', 'Inline', ' ', '🚀'];
+      final patched = _patchInlineStr(bytes, 'B1', runs: pieces);
+      final excel2 = Excel.decodeBytes(patched);
+      final v = excel2['Sheet1'].cell(CellIndex.indexByString('B1')).value;
+      expect(v, TextCellValue('Hello Inline 🚀'));
+    });
+  });
 }