XLSX, CSV, TSV & Markdown Editor - VS Code Extension

This is an open-source project that allows you to view and edit XLSX files with styles, fonts, and colors from Excel files, supporting multiple sheets. Additionally, it provides a table view and editing capabilities for CSV, TSV, and Github Flavored Markdown (.md) files directly in VS Code.

📌 Overview

XLSX, CSV, TSV & Markdown Editor is a powerful Visual Studio Code extension that allows users to open, view, and edit Excel files (.xlsx), CSV, TSV, and Markdown (.md) files directly within VS Code. It provides a seamless, lightweight experience without requiring external software like Microsoft Excel or Google Sheets.

🚨 Important Note: This extension was previously named XLSX Viewer & CSV Editor. It has since been renamed to XLSX, CSV, TSV & Markdown Editor to reflect added support for TSV and Markdown (.md) files.

🚀 Features

XLSX Viewing

✅ Fast & Lightweight - View Excel spreadsheets quickly within VS Code
✅ Retains Formatting - Keeps cell styles, colors, and text formatting
✅ Multiple Sheet Support - View all sheets in your Excel workbook
✅ Toggle Background Mode - Easily switch between Light, Dark, and VS Code (mirrors editor theme) backgrounds
✅ Persistent Theme - Remembers your last used theme across files and sessions
✅ Interactive Table View - Display spreadsheet data in a structured HTML table
✅ Color Detection & Conversion - Converts ARGB Excel colors into CSS-compatible formats
✅ Plain View Mode - Strip all Excel styling to view data like CSV/TSV for cleaner inspection

XLSX Editing

✅ In-Table Editing - Edit XLSX sheets directly in the webview table with Edit, Save, and Cancel actions. ✅ Undo/Redo & Shortcuts - Support for Ctrl+Z/Ctrl+Y, Ctrl+S to save, and Enter to navigate cells while editing. ✅ Toolbar & Settings Panel - Toolbar and settings (sticky toolbar, header options, hyperlink preview, toggle header) are available in the XLSX view for quick access and parity with the CSV editor. ✅ How it works - Changes are made in the webview and persisted back to the original .xlsx file when you click Save. The extension uses ExcelJS to write workbook changes while attempting to preserve styles and formatting where possible. Cancel discards any unsaved changes.

Settings for XLSX Editing

• xlsxViewer.xlsx.firstRowIsHeader — Treat the first row as a header (renders bold).
• xlsxViewer.xlsx.stickyHeader — Make the header row sticky when enabled.
• xlsxViewer.xlsx.stickyToolbar — Keep the workbook toolbar fixed at the top of the editor.
• xlsxViewer.xlsx.hyperlinkPreview — Show hover previews for hyperlinks with Open/Copy actions.

⚠️ Notes & Limitations: Formulas are not automatically recalculated by the webview; very large workbooks or complex charts may be slow to edit. The editor aims to preserve styles and merged-cell behavior where possible.

🆕 Merged Cells & Resizing Support

✅ Merged Cell Support - Full support for both horizontal and vertical merged cells from Excel files, with proper content alignment and original Excel formatting
✅ Interactive Resizing - Drag column/row borders to resize, with visual resize handles, hover effects, and real-time size indicators
✅ Auto-Fit Functionality - Auto-fit button and double-click to auto-fit columns/rows based on content, with smart content-based sizing and width limits

🆕 Excel-like Multi-Selection & Copy

✅ Multi-Selection for Rows/Columns - Hold Ctrl to select/deselect multiple rows or columns, Shift to select a range
✅ Excel/Google Sheets Compatible Copy - Copying and pasting preserves cell structure in Excel/Google Sheets
✅ Improved Selection Management - Visual feedback for multi-row/column selection and selection size info box in the bottom right corner.

CSV & TSV Editing

✅ Table View - View CSV and TSV files in a structured table format
✅ Virtualized Rendering for Large Files - Virtualization (windowed rendering) improves performance and reduces memory usage by rendering only visible rows for both CSV and TSV files
✅ Edit Table Mode - Edit directly in the table with Save, Cancel, and Undo/Redo support
✅ Excel-like Shortcuts - Ctrl+S to save, Enter to move down, Ctrl+Z/Y for undo/redo
✅ Premium UI - Smooth animations, sticky headers, and Apple-like visual feedback
✅ Edit File - Open the CSV/TSV in VS Code’s default text editor when needed\

TSV notes: Copying from the table and pasting into other apps will use tab-delimited data for TSV files; serialization and escaping behave like CSV but use \t as the delimiter for TSV.

Markdown Viewer & Editor

✅ Preview & Edit Modes - Toggle between a rendered Markdown preview and an inline editor with Edit Preview, Save, and Cancel. ✅ Toolbar & Settings - Word Wrap, Line Numbers, Sticky Toolbar and theme toggle available in the editor toolbar. ✅ Local Rendering - Fast, lightweight rendering for common Markdown syntax (headers, lists, code blocks, tables, task lists, images, links). Uses GitHub-Flavored Markdown (GFM) for rendering (tables, task lists, fenced code blocks, etc.). ✅ Theme Support - Respects Light / Dark / VS Code theme using the shared ThemeManager. ✅ Open with Preview - Open .md files with the extension via the editor toolbar or the command palette.

🛠️ Installation

1. Open VS Code
2. Go to the Extensions Marketplace (Ctrl+Shift+X)
3. Search for XLSX, CSV, TSV & Markdown Editor
4. Click Install
5. Open any .xlsx, .csv, .tsv or .md file to start viewing or editing!

Alternatively, you can install it manually using:

code --install-extension muhammad-ahmad.xlsx-viewer

📖 Usage

For XLSX Files

1. Open VS Code
2. Open an .xlsx file
3. View and analyze your data in an HTML table format
4. Use the toggle button to switch the background color
5. Navigate between sheets using the sheet selector

For CSV Files

1. Open any .csv file
2. Click Edit Table to enable in-table editing
3. Click Save to write changes to the CSV file, or Cancel to discard edits
4. To edit raw text, click Edit File (opens VS Code’s default editor)
5. To return to the table view, use Open in Table View (table icon) in the editor toolbar

🛠️ Contributing

We welcome contributions! Feel free to submit issues, feature requests, or pull requests in the GitHub repository.

📜 License

This project is licensed under the MIT License - feel free to use and modify it.

💬 Help & Feedback

If you have any questions, encounter issues, or want to provide feedback, please fill out our Help & Feedback Form.

⭐ Support

If you find this extension helpful, please rate it on the VS Code Marketplace and share it with others!

📢 Follow us for updates!
🔗 GitHub: XLSX, CSV, TSV & Markdown Editor Github Link
🔗 Marketplace: VS Code Extension Link
🔗 Open VSX: Open VSX Link