Frequently Asked Questions
Everything you need to know about PurePDF
General Questions
How does PurePDF compress PDFs without uploading them to a server?
PurePDF uses WebAssembly and the open-source pdfcpu engine to process files locally inside your browser tab. Compression, merging, splitting — all of it happens on your device, achieving 50–70% file size reduction without any server communication.
Is PurePDF really free to use?
Yes. PurePDF gives you 5 operations per day completely free — no registration, no watermarks, no credit card required. Pro plans start at $7.99/month for unlimited operations.
What is the maximum file size PurePDF can handle?
Free users can process files up to 10MB. Pro users get 100MB per file, and Business users get up to 500MB per file.
Technical Questions
How much can PurePDF compress a PDF file?
Typically 50–70% for most PDFs. Image-heavy files can reach up to 78% reduction. Choose from Extreme, Balanced, High Quality, or set a Custom target size based on your needs.
Which browsers work with PurePDF?
Chrome 90+, Firefox 88+, Safari 14+, and Edge 90+. Any modern browser with JavaScript and WebAssembly support will work.
Can I use PurePDF offline?
Yes. After your first visit, PurePDF works completely offline using Progressive Web App (PWA) technology. Files stay on your device even without an internet connection.
Privacy & Security
Is PurePDF safe for sensitive or confidential documents?
Yes. All processing happens locally in your browser using WebAssembly. Your files never leave your device and are never uploaded to any server, making it appropriate for HIPAA-regulated or confidential documents.
Are my files stored anywhere after processing?
Never. Files exist only in your browser's memory while you're working on them and are cleared when you close the tab. PurePDF has a zero-knowledge architecture.
Features & Comparisons
Can PurePDF merge PDFs with different page sizes and orientations?
Yes. PurePDF preserves each page's original dimensions and orientation when merging, so landscape and portrait pages are kept exactly as-is.
How does PurePDF compare to Adobe Acrobat?
PurePDF is free, requires no installation, and processes files entirely in your browser for complete privacy. Adobe Acrobat offers advanced editing and enterprise tools but requires a paid subscription and uploads files to Adobe servers. PurePDF is the best choice when privacy and simplicity matter most.
Does PurePDF add watermarks to processed files?
Never. PurePDF adds no watermarks to any processed files, even on the free tier.