Source LM Reviews and Details

Questions & Answers

1. What makes Source LM unique?

   It builds the source files in memory and pushes them through the notebook page's own upload path, so nothing is written to disk and there is no backend and no account. A JSON or Telegram export becomes as many Markdown sources as it takes, packed to a 400,000-word budget under NotebookLM's 500,000-word cap per source, and a record is never cut in half. Run it again on a grown export and only the new records upload, because the state is read back from the notebook's own source names rather than from a local watermark.

2. Why should a person choose Source LM over its competitors?

   Two practical differences. First, there is no server in the path: the extension acts inside your own signed-in tab, so your files, pages and notebook contents never reach a third party, and the code ships unminified and source-available so you can check that. Second, the price is a one-time $29 licence instead of a subscription, and single sources - one page, one link, one video, one selection - stay free forever; only bulk actions are metered, at 5 free runs a month.

3. How would you describe the primary audience of Source LM?

   People who already work in NotebookLM and have hit its one-at-a-time file picker: researchers and students loading a corpus of papers or transcripts, support and ops teams dumping ticket or chat exports, and anyone who wants a Telegram history, a YouTube playlist or a channel inside a notebook. No technical setup is assumed - it is a Chrome and Edge extension, not a script to run.

4. What's the story behind Source LM?

   It started with a chat export that nobody wanted to split by hand: thousands of messages that NotebookLM would only take as files under its per-source word cap. The first version was a script producing Markdown chunks, and the annoying part was that the chunks still had to be dragged into the notebook one by one. Once the upload could go straight into the open notebook, the disk step disappeared, and everything else - YouTube, link lists, the current page, selected text - was routed through the same path.

5. Which are the primary technologies used for building Source LM?

   TypeScript on Chrome's Manifest V3, bundled with esbuild, with zero runtime dependencies and no framework: the popup is plain DOM. There is no backend - uploads go through the notebook page's own upload endpoint from inside your tab, with a DOM-injection fallback if that path changes, and settings and pending jobs live in chrome.storage. Licence keys are checked directly against the payment provider's public API, so there is still no server of ours in the path.