Local file safety check
Scan files before you open them or feed them to AI.
ScanBeforeOpen analyzes files locally in your browser for known risk patterns. No uploads, no accounts, no trackers.
Secure Scan Lab
Local. Readable. Cautious.
File type, filename, hidden characters, active content, metadata, and AI risks are surfaced.
Preview first, decide calmly
A file does not need to be opened immediately.
ScanBeforeOpen turns the quick double-click into a calm checkpoint: scan, understand, preview in a controlled way, and only open normally when source and content make sense.
What you get immediately
- A clear recommendation without panic language
- An isolated preview for suitable file types
- Clean exports where they are technically sensible
- Transparent limits instead of false safety promises
How it works
1
Select a file
Save the file first instead of opening it directly.
2
Check it locally
The check runs in your browser. The file is not uploaded.
3
Understand risks
You get a plain-language recommendation first, with details available below.
4
Use safe preview or a cleaned copy
Use a safe preview or, when available, a cleaned copy with reduced risk.
Supported MVP file types
Privacy rebuild
Hard-to-detect fingerprints? Rebuild instead of guessing.
Some traces look like normal layout details: character spacing, invisible text layers, old PDF objects, document IDs, or hidden layers. ScanBeforeOpen flags detectable signals and offers rebuild modes that create local copies from visible content.
Four defensive rebuild modes
- Text rebuild: normalizes Unicode and removes invisible markers
- PDF visual flatten: renders pages again as images in a ZIP
- Office visible data: exports visible values or text as new TXT/CSV files
- Image canvas rebuild: creates a new PNG without typical container metadata
This reduces many fingerprint classes, but it is not perfect anonymization and does not replace legal or organizational approval.
Checks by file type
How ScanBeforeOpen examines files
Each file type has different risks. ScanBeforeOpen therefore uses matching local checks, previews, and clean-export options instead of treating every file the same.
Looks for JavaScript, OpenAction, Launch, attachments, forms, links, old PDF objects, document IDs, hidden layers, and prompt risks. Preview and visual flattening use canvas.
Office
Checks macro containers, external relationships, data connections, OLE/ActiveX, comments, metadata, customXml, docProps, and hidden sheets. XLSX preview and visible-data rebuild run isolated.
ZIP
Checks path traversal, risky extensions, nested archives, encryption, entry counts, and compression ratios.
CSV
Detects formula-injection patterns in cells and can export risky formulas as text.
Bilder
Checks image type, metadata, and container hints. Canvas rebuild can reduce typical metadata and many container traces, with possible format or quality changes.
SVG/HTML/Text
Looks for active content, external references, invisible characters, and prompt instructions. Preview stays as source or sanitized text.
What ScanBeforeOpen checks
Human vs. Machine View
Shows whether filenames, extensions, or invisible characters look different to people than to software.
Safe Preview
Displays content in a controlled way without running links, macros, or active content from the original file.
Clean Export
Creates local cleaned copies only where a matching export is available. This reduces risk, but it is not a guarantee.
AI-safe text
Marks or removes suspicious prompt instructions and invisible characters before text goes to AI systems.
Email and messenger help
Helps with attachments from email, chat, and downloads: save first, do not open, then scan.
Privacy by design
No file uploads, no analytics, no accounts, and no active advertising scripts in the launch MVP.
Guides for safer files
Practical defensive guidance for attachments, downloads, Office files, archives, images, and AI workflows.
Check a PDF before opening it
How to defensively review PDFs for active content, attachments, links, and AI risks.
Detect Word, Excel, and PowerPoint macros
Defensive guidance for macros, external relationships, and hidden Office content.
Check ZIP files safely
Recognize risky names, path traversal, dangerous extensions, and ZIP bomb signals.
Avoid CSV formula injection
Why cells starting with =, +, -, or @ can be risky and how to neutralize them.
Remove image metadata
Spot EXIF, GPS, camera, and software metadata in images.
Scan files before AI upload
Surface hidden instructions, metadata, and confidential content before giving files to AI systems.
Limitations
ScanBeforeOpen detects known risk patterns and helps with triage. It is not a complete antivirus, not a malware sandbox, and not a 100% guarantee.
FAQ
Green means: no obvious known patterns found. Still check the source and context before opening the file.
Save it. Do not open it. Scan first.
The first safe action is simple: choose a file and scan it locally.
Scan a file now