Ebook summarizer that exports mind maps you can actually edit

What it does

A browser-based tool that parses EPUB and PDF files, extracts their chapter structure, and feeds the text to Google Gemini or OpenAI using your own API key. It then renders the results as either text summaries or interactive mind maps. Everything happens client-side: your files and API keys stay in your browser, and it caches results locally so you can resume if a long processing job crashes or you close the tab.

The interesting bit

The README explicitly positions this as an escape hatch from Google NotebookLM. The selling point isn’t the AI itself; it’s the data portability and prompt control. You can export the generated mind map as a data file for the Mind Elixir desktop app, and you can completely override the system prompt in text-summary mode—something the README claims NotebookLM refuses to do.

Key highlights

• BYOK browser-only architecture: your API key talks directly to Google or OpenAI, with no proxy server involved.
• Three output modes: text summaries, per-chapter mind maps, or a single whole-book mind map.
• Resume support: caches AI results locally; interrupted jobs pick up where they left off.
• Custom prompt templates with optional full override of the system prompt (text summary mode only).
• Chapter grouping: merge small chapters into labeled groups before sending them to the AI.

Caveats

• Whole-book mind maps can fail on long books because of model context limits.
• The online interface is view-only; deep editing requires exporting to the separate Mind Elixir desktop app.
• Full prompt override is restricted to text summary mode.

Verdict

Worth a look if you regularly digest long technical books or papers and want structured, portable output without shipping your reading list to a backend. Skip it if you don’t have an AI API key or if you need native deep editing inside the browser itself.