About this tool
The file preview tool reads common files into browser memory and chooses a native browser preview or an open-source parser for each format. Images, audio, video, PDFs, text, Markdown, DOCX, and XLSX/CSV can be inspected in one place without uploading the file.
ZIP files first show a folder tree. Select an entry and the same preview pipeline is reused for its contents, so you can inspect one document or image without extracting the whole archive to disk.
How to use it
Choose or drop a file
Upload one file and the tool selects a preview strategy from its MIME type and extension.
Inspect the contents
Text and Markdown are scrollable, spreadsheets have sheet tabs, and PDFs, images, and media use browser previews.
Browse a ZIP
Upload a ZIP, expand the tree, and select any file to preview it. Unsupported binary entries remain downloadable.
Clear and preview another file
The preview stays in the current page memory only; clear it before choosing another file.
Supported range and limits
- Processing
- Local browser memory
- Previewable
- Images, audio/video, PDF, TXT/code, Markdown, DOCX, XLSX/XLS/CSV
- Archives
- ZIP tree plus previews for supported entries
- Open-source pieces
- fflate, docx-preview, SheetJS, marked, and native browser media/PDF support
- Unsupported or limited
- RAR, 7z, encrypted archives, unknown binaries, and complex Office features
- Large text limit
- Text files over 300,000 characters show only the beginning to keep the page responsive
When you would use it
Check an attachment quickly
Inspect an image, PDF, spreadsheet, or document before opening a desktop application or downloading the whole archive.
Inspect one archive entry
For project bundles, document packs, or build artifacts, open only the file you need to verify.
Review sensitive files locally
Contracts, configs, logs, and internal attachments stay in the browser instead of being sent to a third-party preview service.
What to know before you start
- Parsing happens locally in the browser. Very large files, complex DOCX files, encrypted PDFs or ZIPs, RAR/7z archives, and unknown binary formats may not preview.
- XLSX/CSV output is a bounded quick snapshot. It does not reproduce every Excel chart, formula, macro, conditional format, or cell style.
- Markdown preview filters dangerous protocols and raw HTML. Do not treat it as a complete security audit of an untrusted document.
Related concepts
- Blob URL
- A temporary browser address for file data held in memory, useful for image, media, and PDF previews.
- MIME type
- A content-type hint carried by a file. When it is missing, the tool also checks the filename extension.
- ZIP entry
- A file record inside an archive. The tool extracts it in memory and sends it through the matching previewer.