NotebookLM takes sources one at a time, through a file picker. Source LM takes the batch: a JSON export becomes Markdown files packed under the 500k-word source cap, a YouTube playlist becomes one source per video. No downloads, no backend, no account. The extension ships unminified and the source is public — "no backend" is a claim you can check, not trust.
I built Source LM because NotebookLM's file picker is one-at-a-time, and I had a 40 MB Telegram export I wanted to ask questions about.
It packs any JSON with records into as many Markdown files as it takes, budgeted under NotebookLM's 500,000-word per-source cap, never splitting a record across files. Re-run it later and only the new records go up. YouTube is the other half: a playlist or a channel becomes one source per video, transcripts and optionally the top comment threads, from buttons inside YouTube's own UI.
Two things I care about more than the feature list:
Nothing is downloaded and nothing leaves your machine. The popup builds the files in memory and sends them to the notebook page's own origin. There is no backend and no account — your Google session never touches a server of mine.
The extension ships unminified and the source is public (PolyForm Noncommercial), so "no backend" is a claim you can check rather than trust.
Free plan is 5 bulk uploads a month; $29 once for unlimited, no subscription. For launch week, PHLAUNCH takes 50% off — until Sept 5.
Happy to answer anything — especially about the chunking, which is where all the real work went.
Hi Product Hunt 👋
I built Source LM because NotebookLM's file picker is one-at-a-time, and I had a 40 MB Telegram export I wanted to ask questions about.
It packs any JSON with records into as many Markdown files as it takes, budgeted under NotebookLM's 500,000-word per-source cap, never splitting a record across files. Re-run it later and only the new records go up. YouTube is the other half: a playlist or a channel becomes one source per video, transcripts and optionally the top comment threads, from buttons inside YouTube's own UI.
Two things I care about more than the feature list:
Nothing is downloaded and nothing leaves your machine. The popup builds the files in memory and sends them to the notebook page's own origin. There is no backend and no account — your Google session never touches a server of mine.
The extension ships unminified and the source is public (PolyForm Noncommercial), so "no backend" is a claim you can check rather than trust.
Free plan is 5 bulk uploads a month; $29 once for unlimited, no subscription. For launch week, PHLAUNCH takes 50% off — until Sept 5.
Happy to answer anything — especially about the chunking, which is where all the real work went.