About Kobra PDF

Kobra PDF is a free collection of 31 PDF tools that run entirely in your web browser. It is built and maintained by Piero Nanni as an independent project. There are no accounts, no usage limits, and no watermarks.

Why everything runs in your browser

Most online PDF tools upload your document to a server, process it there, and send it back. That means contracts, bank statements, and medical records sit, at least for a while, on a computer you do not control. Kobra PDF takes the other route: the processing code is downloaded to your browser and works on your file locally, so the document itself is never transmitted. Read how this works and how to verify it.

Built on proven open source software

The tools rely on well-known open source libraries rather than custom PDF parsing:

• pdf-lib: creating and modifying PDF documents: merging, splitting, stamping, signing, and filling forms
• PDF.js: rendering pages to images and reading text, the same engine as the PDF viewer built into Firefox
• qpdf: AES-256 encryption, decryption, and lossless optimization, compiled to WebAssembly
• Tesseract.js: optical character recognition for scanned documents

Contact

Questions, bug reports, and feature requests are welcome. Email [email protected] or find Piero Nanni on GitHub.