About the Multi-File Reader Tool

The Multi-File Reader is a fast, privacy-first viewer built to open many files side by side in a clean, tabbed workspace. It’s ideal for developers comparing logs, analysts scanning datasets, designers previewing media, and anyone who needs to inspect multiple files without switching apps. Everything runs locally in your browser no uploads, no servers so you stay in full control of your data from start to finish.

Use it to preview images, videos, audio, PDFs, and text; dive into the raw source of code and documents; or examine the byte-level structure of any file in a detailed hex view. The interface is designed to reduce friction: drag-and-drop files in, switch tabs instantly, toggle view modes with one click, and keep moving. It’s quick to learn, dependable under heavy workloads, and comfortable for both single-file focus and multi-file comparison.

Viewing capabilities

Preview mode: See a visual or embedded representation when possible. This mode supports images (with zoom and pan), videos (with controls), audio (with a simple player), PDFs (page-by-page rendering), and many common text formats with automatic formatting where appropriate.
Raw text mode: View plain, unstyled content for text-based files such as TXT, CSV, JSON, XML, HTML, Markdown, logs, and source code. Long lines wrap intelligently with an option to toggle wrapping for wide content. Useful for quick scanning, copying, or searching text.
Hex mode: Inspect the exact byte structure with a classic hex viewer: offset column, hexadecimal bytes, and an ASCII panel for printable characters. Adjustable bytes-per-row and live selection highlight help you correlate positions precisely. Perfect for binary formats, debugging, and forensic checks.

Key features

Tabbed interface: Open many files at once. Each file gets its own tab with clear names and type-aware icons for quick identification.
Broad file support: Preview media and PDFs, read text and code in raw form, and switch to hex for any binary or unknown type.
Drag and drop: Drop files anywhere in the app window to add them. You can also click a button to select from your device.
Instant switching: Jump between files and view modes with minimal lag, even for larger datasets or long logs.
Local-only processing: Files never leave your device. All reading, parsing, and rendering happen in your browser.
Lightweight controls: Zoom, seek, page through, wrap lines, or change hex density without losing your place.
Persistent session: Keep working across many files in one session. Clear all with a click when you’re done.
Error clarity: If a file can’t be read or previewed, you’ll get a clear, human-friendly explanation and alternatives.

How to use the Multi-File Reader

Step 1: Add files
Drag and drop your files into the window or click “Select Files” to choose them from your device. You can add more files at any time.
Step 2: Navigate files
All files appear in the sidebar and as tabs. Click a filename in the sidebar or select its tab to bring it into focus.
Step 3: Switch views
Use the “Preview,” “Raw Text,” and “Hex” controls at the top of the viewer. The tool remembers your current mode per file during the session.
Step 4: Manage files
Close individual tabs to declutter, or use “Clear All” to reset the workspace and start fresh.

Supported file types

Media and documents

Images: PNG, JPG/JPEG, WebP, GIF, BMP, TIFF (preview with zoom/pan; animated GIFs play when supported).
Video: Common browser-supported formats (e.g., MP4/H.264, WebM). Playback controls include play/pause, scrub, and volume.
Audio: Formats supported by your browser (e.g., MP3, WAV, OGG). Simple player with timeline and volume.
PDF: Embedded, paginated preview with basic navigation and zoom for comfortable reading.

Text and code

Plain text: TXT, LOG, CSV, TSV, JSON, XML, YAML, HTML, Markdown, and similar text-based formats in raw view.
Source code: Reads popular languages (JS, TS, Python, C/C++, Java, Go, Rust, etc.) as plain text for quick inspection and copy.
Large logs: Efficient streaming and line wrapping help keep big files readable; use search to jump to relevant sections.

Binary and unknown types

Hex analysis: Any file can be opened in hex mode to reveal byte content, offsets, and ASCII representation.
Fallback behavior: If preview isn’t supported (e.g., proprietary formats), raw text and hex remain available for inspection.

Privacy and security

Client-side only: Files are never uploaded or transmitted; everything runs locally in your browser.
No sign-in: Full functionality without accounts, tracking logins, or background syncing.
Ephemeral handling: Data resides in memory for the duration of your session. Close the tab to clear the context.
Sensitive data friendly: Suitable for confidential documents, private media, and proprietary binaries on your device.

Performance and limits

Device dependent: Performance scales with your CPU, memory, and storage speed. Modern browsers offer the best experience.
File size: Very large media or massive logs may open more slowly. If the interface becomes sluggish, close unneeded tabs.
Batch size: You can load many files at once. For exceptionally large sets, add them in waves to keep navigation snappy.
Browser constraints: Memory caps vary by browser and platform. If you encounter warnings, reload and open fewer files at a time.

Viewer controls and tips

Preview mode

Images: Zoom to examine details; pan by dragging; reset zoom with a single click when available.
Video: Use the timeline to scrub; spacebar typically toggles play/pause; mute and volume controls are accessible.
Audio: Seek through the waveform/timeline and adjust volume for quick sampling of clips.
PDF: Navigate pages with arrow controls or the page selector. Zoom to improve readability of small text.

Raw text mode

Line wrapping: Toggle wrapping to handle long lines in logs, JSON, or minified code.
Search: Use the built-in search to find keywords, error codes, or field names in large files.
Encoding: Files are read as UTF-8 by default; unusual encodings may display unexpectedly re-save from the source if needed.

Hex mode

Layout: View an offset column, hex bytes, and ASCII side-by-side to correlate positions and characters.
Density: Adjust bytes-per-row to match your analysis style (commonly 16 bytes per row for readability).
Selection: Drag to select byte ranges; highlighted regions help pinpoint offsets for documentation or debugging.

Best practices

Name files clearly: Short, descriptive filenames make tabs easier to scan and manage.
Group by type: Open related files together (e.g., logs from the same time window, design assets from one project) to compare quickly.
Use the right view: Prefer Preview for media/PDF, Raw Text for structured text and code, and Hex for binary and unknown formats.
Trim noise: Close tabs you no longer need to keep navigation responsive during large investigations.

Use cases

Debugging sessions: Open server logs, config files, and sample payloads together; search for errors and compare timestamps.
Data inspection: Peek into CSV/JSON datasets in Raw Text, verify delimiters, and spot malformed rows before importing.
Design reviews: Preview multiple images and PDFs in tabs to compare versions and check asset details.
Binary checks: Use Hex mode to verify magic numbers, headers, and byte offsets for custom or unknown formats.
Security triage: Safely examine suspicious files in hex without executing anything or uploading externally.

Accessibility

Keyboard navigation: Navigate the sidebar, tabs, and viewer controls using standard keyboard focus and shortcuts where available.
Readable UI: Clear contrast and scalable text aim to reduce eye strain during long review sessions.
Screen reader friendly: Key controls include accessible labels and statuses to support assistive technologies.

Troubleshooting

Unsupported preview: If a file type cannot be previewed, try Raw Text or Hex mode to inspect content.
Corrupted file: If loading fails, re-save the file from its original application or verify the download isn’t incomplete.
Slow performance: Close background tabs, reduce the number of open files, or switch to Raw Text for faster navigation.
Encoding issues: For misread characters, convert the file to UTF-8 in your editor and reopen it here.
Large PDFs or media: Give the preview a moment to render; use zoom selectively and avoid switching too rapidly between large pages.

Frequently asked questions

Are my files uploaded? No. Everything happens in your browser, and your files stay on your device.
Can I edit files? This tool is a viewer. You can read and inspect, but not modify files. Make edits in your preferred editor, then reload to review changes.
How many files can I open? There’s no hard limit, but practical limits depend on your device memory and browser. Add large batches gradually for best responsiveness.
Does it support syntax highlighting? Raw Text prioritizes performance and readability. If you need full highlighting or linting, open the file in a dedicated code editor and use this tool for quick side-by-side viewing.
What about password-protected PDFs? Encrypted PDFs may not render if the password cannot be provided within the browser preview. Open them in a dedicated PDF reader to unlock first.

Shortcuts and workflow tips

Multi-select add: Hold Shift/Ctrl (or Command on macOS) when picking files to add batches in one step.
Tab management: Reorder or close tabs to keep the most relevant files at hand; the sidebar mirrors tab state for clarity.
Search strategy: Use Raw Text search to jump to error IDs, timestamps, or keys. Review nearby context and then flip to Hex if needed.

Compatibility

Modern browsers: Best in current versions of Chrome, Edge, Firefox, and Safari with JavaScript enabled.
Cross-platform: Works on Windows, macOS, Linux, and capable mobile devices. Desktop offers the most comfortable multi-tab experience.
No plugins: No extensions or external players are required; the tool uses native browser capabilities.

Find our tool

Multi-File Reader, File Reader, View Multiple Files, Online File Opener, Multi-File Viewer, Document Reader, Code Viewer, Text Reader

Multi-File Reader