PDF Repair handles corrupted cross-reference tables, broken headers, damaged page trees, invalid metadata, detached objects, and encryption flags. It uses pdf-lib's lenient parser to scan for valid objects and rebuild the document structure. Files that won't open, show blank pages, or crash viewers are the most common candidates for repair.

The tool loads your damaged PDF using a lenient parsing mode that skips over malformed objects and rebuilds the xref table from whatever valid objects it finds. It then saves a clean copy with a new cross-reference table, valid trailer, and correct byte offsets for every surviving object. This is the same technique used by qpdf and Ghostscript.

For files with physically missing content (bytes overwritten with zeros), the page will exist in the repaired file but render as blank. However, the tool can still extract readable text from partially damaged content streams. The diagnostic report will tell you exactly what was recovered and what was lost.

In most cases, yes. Text, images, fonts, and page layout are preserved when the underlying objects are intact. The repair focuses on fixing the document structure — not re-encoding content. Metadata like author and title may be cleaned up if they were causing corruption.

Absolutely. PDF Repair runs entirely in your browser using JavaScript. Your files are read locally, processed locally, and the repaired output is generated on your device. No data is uploaded to any server. You can verify this by checking your browser's Network tab during repair.

Yes. Switch to batch mode to queue multiple files. The tool will scan and repair each one, showing per-file status and a diagnostic report for each. You can download all repaired files as a single ZIP archive.