Source LM

Get sources into NotebookLM in bulk

Source LM is a Chrome extension that gets material into a NotebookLM or Gemini Notebook notebook in bulk, without downloading anything to disk.

Three inputs

• JSON datasets — a JSON export (e.g. a Telegram chat export) is split into Markdown files word-budgeted under NotebookLM’s 500,000-word per-source cap. Records are never split across files, and re-running uploads only the new records.
• YouTube — “Add to notebook” buttons injected into YouTube’s own UI add the current video, a playlist, or a channel’s latest N videos as one source per video, with optional top comment threads.
• Links and pages — a pasted URL list, the current page, or a right-click on selected text.

Source management extras

• Batch source deletion
• Duplicate-source finder
• Broken-source listing with manual replace
• Source filter box

No backend, no account, no telemetry: the extension talks only to the notebook page’s own origin. Source-available under the PolyForm Noncommercial License 1.0.0, shipped unminified.

Pricing: free plan is 5 bulk actions per month, single sources always free. Pro is $29 one-time, not a subscription.