File Attribute Viewer

A File Attribute Viewer is a tool that examines and displays all available metadata and properties of any file. It shows basic attributes like name, size, type, and modification date, along with advanced attributes like magic bytes, character encoding, entropy levels, and content classification. It helps you understand exactly what a file contains and its technical characteristics.

The tool displays file name, file extension, file size (in bytes and human-readable format), MIME type, file category (image, audio, video, document, archive, code, etc.), last modified timestamp with relative age, estimated file permissions, detected format from magic bytes, content type (text vs binary), character encoding, Shannon entropy with interpretation, and text statistics (character, word, and line counts).

The browser File API only exposes the lastModified property of files. Creation date (birth time) and access date are filesystem-level attributes that require native OS access. Browsers intentionally restrict this information for security and privacy reasons. To view full filesystem timestamps, use your operating system's file properties dialog or command-line tools like stat on Linux/macOS.

Absolutely. The File Attribute Viewer processes everything locally in your browser using JavaScript typed arrays. Your files are never uploaded to any server - all analysis, including magic byte detection, entropy calculation, and content classification, happens entirely on your device. No data is sent over the network, logged, or stored.

Magic bytes are a sequence of bytes at the beginning of a file that uniquely identify its format. For example, JPEG files start with FF D8 FF, PNG files with 89 50 4E 47, and PDF files with 25 50 44 46. Unlike file extensions (which can be changed arbitrarily), magic bytes are embedded in the file data and provide an authoritative way to determine the true file format.

Shannon entropy measures the randomness or unpredictability of byte values in a file. Low entropy (0-3 bits/byte) indicates highly structured data like plain text. Medium entropy (4-6) suggests mixed content or moderate compression. High entropy (7-8) indicates compressed, encrypted, or packed content - commonly seen in archives, encrypted files, or packed executables.

The tool reads the first 4,096 bytes of the file and counts the proportion of printable byte values (letters, numbers, punctuation, whitespace, and extended ASCII). If more than 85% of the bytes are printable, the file is classified as text. Otherwise, it's classified as binary. This heuristic is reliable for most files but may misclassify binary files with large ASCII string sections or text files with heavy encoding.

Yes. The File Attribute Viewer is useful for initial security triage. Check if a file's extension matches its actual format (detected via magic bytes), assess entropy levels for packed or encrypted payloads, verify MIME type consistency, check for hidden file indicators (dotfile prefix), and inspect text files for encoding anomalies. For comprehensive security analysis, combine with specialized tools like the Suspicious File Pattern Detector.

Yes - 100% free, forever. No signup, no account creation, no premium tier, no usage limits, and no ads. Analyze as many files as you need, as often as you need. All processing is done locally in your browser with zero server uploads. The tool will always remain free and private.