Modern browsers can run powerful file tools using WebAssembly and browser APIs.
- "Stays on your device" Work happens locally and the file is never uploaded, like Compress PDF .
- "Deleted after an hour" The file was uploaded; you're trusting a deletion policy.
- Sensitive file Prefer the first kind: no upload means there is nothing to delete.
| Tool | Best when | Skip when | Privacy fit |
|---|---|---|---|
| Just Compress | Quick private file jobs. | AI reading or deep editing. | No upload. Free. PDF outputs include a small app logo watermark. |
| Cloud PDF and media tools | Non-sensitive files, collaboration, heavy server processing, shared workflows. | Sensitive files that only need a simple mechanical file operation. | Often secure, but many require upload, server processing, and deletion policies. |
| ChatGPT / AI | Summarizing, reasoning, rewriting, comparing, extracting meaning from content. | Only making a file smaller, converting it, or adding a simple mark. | Useful when content analysis is needed; unnecessary exposure for simple file tasks. |
| Adobe / full editors | OCR, redaction, forms, certificates, advanced page editing, professional workflows. | One quick compression or conversion where no full editor is needed. | Powerful, but heavier than needed for simple no-upload file work. |