File Info Viewer

📖 Tool Introduction

File Info Viewer is a completely offline, read-only metadata tool that answers questions about a file the moment you drop it in. It never modifies, compresses or uploads your file; it simply gathers the attributes the browser and the operating system already know and lays them out as one clean sheet: the file name, its extension, the MIME type, the exact byte count together with a human-readable size, the last-modified timestamp, an auto-detected category, and, for plain-text files, an estimated line count obtained by scanning newline bytes one by one. When you receive an unsolicited attachment and want to confirm its real type and footprint before archiving it, or when you need a quick count of how many lines a log has before writing a script, the answer appears instantly without any server round-trip. The tool also sniffs the encoding from the first 256 kilobytes of content: a strict UTF-8 decode marks the file as UTF-8, while any NUL byte forces it into the binary bucket, so an image renamed as a .txt is never mistaken for text. The whole report can be copied to the clipboard in one click or saved as a .txt file for the record. Because every calculation happens inside your own browser, there is nothing to send out and nothing to collect, which makes the viewer equally suitable for sensitive documents on isolated intranet machines as for everyday cloud workstations. The interface stays deliberately minimal: a dashed drop zone on top, a single spec-sheet of label and value rows below, and a compact toolbar for copying and downloading the report.

✨ Key Features

• Read-only inspection: it only reads File attributes and sniffs content, never altering the original
• Smart categories: MIME and extension together classify text, images, audio-video and binary
• Line estimation: text-like files are scanned byte by byte for the 0x0A newline code
• Encoding sniffing: strict UTF-8 decoding plus NUL-byte detection separates text from binary
• Dual sizes: exact bytes with thousands separators alongside KB, MB and GB
• Privacy-first: every computation is local, with zero uploads of your files

📝 How to Use

1. Drag the file you want to inspect onto the dashed area, or click it to pick a file
2. The tool reads and analyzes the file locally, filling the sheet instantly
3. Read the category badge and each field; text files also show an estimated line count
4. Click Copy report to write the whole sheet to your clipboard
5. Click Download report to save file-info-report.txt for your records

⚠️ Notes

• Size limit: files over 200 MB trigger a friendly message instead of freezing the browser
• Estimated lines: line counts are newline-based, and a final line without a newline is counted once
• MIME is a hint: the MIME type comes from the browser; trust the sniffed category more
• Modified time: the timestamp comes from the filesystem; copied-to-clipboard files may lose it
• Fully offline: no network request is ever made, so it works on slow or isolated networks

🧰 Common use cases

Use this tool whenever you need to know exactly what a file is before you do anything else with it. Developers inspecting a downloaded binary can confirm its real type instead of trusting the extension; writers checking an exported draft can see whether line endings and encoding stayed intact; teachers grading student uploads can spot empty or zero-byte files in one glance; photographers comparing a fresh camera photo against a compressed copy can read the exact byte difference. The detector samples the first chunk of bytes, so it stays fast even on huge files, and the line counter scans byte by byte rather than loading the whole text, so gigabyte-sized logs will not freeze the page. Everything you see here is derived from the file itself in your browser, which means the same answer will appear offline and on any device without ever sending your document to a server. If a reported type looks surprising, trust the detected MIME and the sniffed flags over the old extension, because browsers and operating systems guess types from content far more often than from filenames.