KastorFlowUpdated October 21, 2026
The NotebookLM Chrome extension that checks your sources
Works on Gemini Notebook (notebook.google.com) and notebooklm.google.com.
KastorFlow is a Chrome extension for NotebookLM, now called Gemini Notebook. Gemini Notebook answers from the sources you give it, so KastorFlow works on the sources: it audits a notebook and flags what to drop, shows which kinds of source are missing, and finds sources to fill those gaps, adding only the ones you approve. It also imports a whole YouTube playlist as one source, saves AI chats and pages, keeps notebooks current with automations and links them to Obsidian both ways. Free to install, with no account and no API key.
What it adds, by job
| Job | Tool | Plan |
|---|---|---|
| Check sources | Audit and enrich: flag sources to drop or review, see missing kinds of source, fill the gaps with sources you approve | Pro+ |
| Find sources | Build research notebook: type a topic and get a notebook of sources. On Pro, preview every source and keep the ones you want | Free: 5 a month, every source found is added. Pro: no monthly limit, with preview |
| Collect | A whole YouTube playlist as one source, videos in order | Free: 1 a month. Pro: 50 a month |
| Collect | Video frames: a video's slides beside its transcript, as one PDF | Free, 3 a month |
| Collect | Save ChatGPT, Claude, Gemini, Perplexity and Grok chats; web pages, selected text, a page as PDF | Free (chats: 5 a day) |
| Collect | Several links, open tabs, CSV files and RSS feeds at once | Pro |
| Organize | Library map, workspace search, tags, collections, duplicate finder | Free |
| Organize | Tag with AI, folders, merge notebooks, move and copy sources | Pro (AI tags: 20 sources a month free) |
| Keep current | Automations: 10 triggers, 16 actions; scheduled refresh | Pro |
| Keep current | Notebook autopilot: build, audit and fill gaps on a schedule | Pro+ |
| Share | Generate Studio artifacts across notebooks; export to Markdown; Audio Overviews as a podcast feed of your own | Pro |
| Connect | Obsidian both ways, Readwise, Slack, Discord | Pro+ |
| Connect | Send flashcards to Anki | Free: 1 a month; Pro: no limit |
Plans and limits as of October 21, 2026. Every tool by plan
Choose KastorFlow if
- Your notebooks need better sources, not just more of them.
- You want imports, tags and refreshes to happen on their own.
- You learn from long YouTube courses or conference talks.
- You keep notes in Obsidian, highlights in Readwise or flashcards in Anki.
Side by side: KastorFlow vs Kortex · KastorFlow vs NotebookLM Tools · KastorFlow vs NotebookLM Web Importer · KastorFlow vs ExtendLM · KastorFlow vs YouTube to NotebookLM · every NotebookLM extension, feature by feature
Guides: YouTube to NotebookLM · Folders in NotebookLM · NotebookLM MCP · Save ChatGPT and Claude chats · Export notes and artifacts
Plans
- Free: $0, no account needed to start.
- Pro: for the first 100 subscribers, $2.99 a month for the first 12 months (then $7), or $19 for the first year (then $47.88).
- Pro+: for the first 100 subscribers, $4.99 a month for the first 12 months (then $11.99), or $29.99 for the first year (then $115.08).
Your data
- Your notebooks stay in your own Google account. KastorFlow never sees your Google password.
- KastorFlow keeps a working copy of your library in your browser, so search and the map work on your own machine.
- AI features are off until you allow them. When you use one, the text it needs goes through KastorFlow's servers to Gemini without your name, email, account ID or IP address attached. We don't keep it, and Google doesn't use it to improve its products.
- No browsing history is collected, and no data is sold.
Better sources in, better answers out. Free to install.
Add to ChromeQuestions
Is there an official NotebookLM Chrome extension?
No. Google doesn't make a Chrome extension for NotebookLM or Gemini Notebook. Every NotebookLM extension in the Chrome Web Store, KastorFlow included, is made by an independent developer.
Does KastorFlow work with Gemini Notebook?
Yes. Google renamed NotebookLM to Gemini Notebook in July 2026. KastorFlow works on notebook.google.com and on notebooklm.google.com. What changed with the rename
What does KastorFlow do that Gemini Notebook doesn't?
It audits a notebook's sources and flags the ones to drop or review, shows which kinds of source are missing, and finds sources to fill those gaps, adding only the ones you approve. It also imports a whole YouTube playlist as one source, runs automations, publishes Audio Overviews as a podcast feed of your own and links notebooks to Obsidian both ways.
Is KastorFlow free?
Free to install, with no account and no API key. The Free plan includes the library and search, tags, single-link imports (10 a day), saving AI chats (5 a day), 5 research notebook builds a month and Studio downloads. Compare plans
Where does my data go?
Your notebooks stay in your own Google account, and KastorFlow never sees your Google password. KastorFlow keeps a working copy of your library in your browser so it can search and organize it. AI features are off until you allow them. When you use one, the text it needs goes through KastorFlow's servers to Gemini without your name, email, account ID or IP address attached. We don't keep it, and Google doesn't use it to improve its products.