Repair PDF
Rebuild a corrupt PDF that won't open and linearize it for fast web viewing.
Repair PDF online, free and private
A PDF that won't open — “the file is damaged”, “cannot open document”, a blank viewer — is usually not lost. Most corruption affects the file's cross-reference table (the index that tells a viewer where each object lives) or its trailer, while the actual page content is still intact. Rebuilding that structure recovers the document.
PDFToolz repairs files with qpdf, the same battle-tested engine used by professionals, compiled to WebAssembly so it runs in your browser. It re-parses the file, reconstructs the damaged structure, and also linearizes the output — reordering it for “fast web view” so page one appears before the rest of the file has downloaded. Nothing is uploaded in the process.
How to repair pdf in your browser
- 1
Add the damaged PDF
Click ‘Select PDF file’ or drop the file onto the page — even if other programs refuse to open it.
- 2
Rebuild the file
Press ‘Repair PDF’. qpdf re-parses the document, reconstructs the cross-reference table and object structure, rewrites everything cleanly, and linearizes the result for fast web viewing.
- 3
Download the repaired PDF
The rebuilt file downloads immediately. Open it in your PDF viewer to confirm the content — in most cases the document comes back completely.
Why use PDFToolz for this
Professional-grade repair engine
The repair is performed by qpdf, a widely trusted open-source PDF engine, compiled to WebAssembly. It recovers broken cross-reference tables, truncated trailers and malformed objects wherever recovery is possible.
Fast web view included
The output is linearized: its objects are reordered so the first page can render while the rest is still downloading. Websites and email previews open linearized PDFs noticeably faster.
Your files stay private
The damaged file is repaired on your device — it is never uploaded. That matters, because broken files are often the important ones: invoices, contracts, theses.
Free with no limits
Repair as many files as you need — no account, no watermark, no size games.