Have you ever wanted to feed your EPUB contents into an LLM (Large Language Model) or edit them to your liking? While existing online tools are convenient, uploading private books to a remote server often feels uncomfortable due to security and copyright concerns.
To solve this, I developed epub2everything, an EPUB conversion suite where every process is completed entirely within your browser.
Convert EPUB books into LLM-ready context chunks (Markdown, DOCX, PDF) locally in your browser. Privacy-focused, secure, and fast.
[!IMPORTANT] Disclaimer This tool is intended for personal use. Please use caution when handling copyrighted content and comply with the terms of service of each platform and copyright laws.
Why I Built This
The primary motivation was my desire to feed my self-scanned EPUBs into NotebookLM.
Currently, NotebookLM does not natively support EPUB files. Furthermore, it is often said that AI understands document structures more accurately when provided in Markdown format.
Another major reason for custom development was that most existing EPUB converters are “online” services that require uploading files to a server. I had strong reservations about sending my extremely private library data to an unknown server.
“Then, why not just do everything on the browser (client-side)?”
With that thought, I aimed for a tool that performs parsing, conversion, and image extraction 100% locally in the browser’s memory.
4-in-1 Tool Suite: Core Features
The suite provides four specialized tools to suit different needs.
1. Markdown Conversion
Optimized for LLM input. You can save tokens by choosing whether to extract images or remove links.
2. Word (DOCX) Output
Converts EPUB content into high-quality, editable documents, useful for research and documentation.
3. PDF Conversion
Outputs clean layouts suitable for viewing and archiving.
4. Gallery Mode (Image Extraction)
Preview all images in the book and download specific ones or export them as a ZIP archive.
Other UX Features
- Global Drag & Drop: Interaction from anywhere on the screen.
- PWA Support: Installable on desktop and mobile for offline use.
- Token Estimation: Real-time calculation of LLM token counts for converted text.
Now Available as OSS
This project is open-source under the MIT license on GitHub.
Contribute to tamara1031/epub2everything development by creating an account on GitHub.
If you find this tool useful, I would be very encouraged if you could give it a Star on GitHub. As an OSS project, bug reports and pull requests for improvements are also welcome. Feel free to fork and customize it to your heart’s content.
Privacy-First Philosophy
The most significant feature of “epub2everything” is that all processing happens within the browser. No files are ever sent to a server. Parsing, image extraction, and document generation all take place within your device’s memory.
Conclusion
I’m amazed by the era we live in, where “vibe coding”—following your intuition of what you “want”—allows you to build the tools you need in an instant.
Next time you have an idea for a tool you wish existed, give it a try!
