Notebook — a NotebookLM-style clone

A local-first Next.js workspace that mirrors the parts of Google NotebookLM that matter: chat grounded in your sources, a two-host audio overview, and a growing library of structured artifacts (study guide, briefing, FAQ, mind map, quiz, flashcards, timeline) — all persisted to a single SQLite file.

Feature tour

Sources

• Upload PDF, paste text, add a URL, or drop a YouTube link — the transcript is fetched automatically.
• Each source is auto-chunked (~800 chars), embedded with text-embedding-3-small, and given a short OpenAI-generated summary + key entities on ingest.
• Click any source to preview it with the summary pinned at the top and a Regenerate button.

Chat

• Streams gpt-4o-mini over SSE, grounded in the top-K retrieved chunks of the notebook (or your current selection).
• Inline [S1] citation pills — click one to open the exact source chunk highlighted in the preview.
• Save as note on any assistant reply, Export the whole chat as Markdown, Clear to reset.

Audio Overview

• Deep Dive / Brief / Debate styles + optional Focus instruction.
• Voice picker for both hosts (10 Kokoro voices — Heart, Bella, Sarah, Michael, Adam, Onyx, Emma, George…).
• Per-line timings → clickable transcript that seeks the audio element; the currently-playing line highlights.
• Speed chips (1× / 1.25× / 1.5× / 2×) + one-click Download of the WAV named after the notebook.
• Jobs survive restarts; the latest ready job auto-loads on revisit.

Studio artifacts

All generate from the selected sources (or all sources if none are picked) and persist per-notebook. Regenerating replaces the previous copy.

• Study guide · concepts, terms, practice questions (Markdown)
• Briefing doc · TL;DR + key themes + open questions (Markdown)
• FAQ · 8–12 Q&A pairs (Markdown)
• Mind map · interactive radial SVG with pan/zoom, click a node for detail
• Quiz · 8–12 multi-choice questions with immediate feedback and scoring
• Flashcards · 14–20 cards, flip + rate (1 again / 2 got it, ← / →, Space)
• Timeline · chronological events extracted from the sources

Notes

Collapsible Notes card in the Studio column. Manual notes (Markdown) + Save-as-note on any chat reply. Inline edit + delete.

Persistence

• data/notebook.db (SQLite, WAL) stores notebooks, sources, embeddings (as BLOBs), messages, jobs, artifacts, and notes.
• Rendered WAVs live at data/audio/<jobId>.wav and are garbage-collected when the notebook is deleted.

Multi-notebook home

/ is a grid of notebook cards with title, emoji, source count, and last-updated. /n/[id] is the workspace.

Keyboard

• ⌘K focus chat · ⌘U open upload · ? or ⌘/ toggle shortcut cheat sheet · Esc close dialogs.

Quick start

cp .env.example .env                 # add OPENAI_API_KEY
npm install
npm run dev                          # http://localhost:3000

The first Generate of an audio overview downloads ~300 MB of Kokoro ONNX weights (cached in ~/.cache/huggingface). Subsequent generations are fast.

Without an API key the app still boots and persists, but chat / embeddings / summaries / artifacts degrade to small demo placeholders. The podcast pipeline still runs end-to-end in demo mode.

Testing

npm run build                # scripts use `next start`, so build first
npm run smoke:persist        # ~30 s: notebook + source survive a restart
npm run smoke                # ~2–10 min: chat, every artifact kind, notes CRUD, audio WAV

Architecture

app/
  page.tsx                                     notebook grid (home)
  n/[id]/page.tsx                              workspace

  api/
    notebooks/route.ts                         list + create
    notebooks/[id]/route.ts                    get/patch/delete
    notebooks/[id]/sources/route.ts            upload text / PDF / URL / YouTube
    notebooks/[id]/chat/route.ts               SSE streaming RAG chat
    notebooks/[id]/artifacts/route.ts          all 7 artifact kinds
    notebooks/[id]/audio/route.ts              start an audio job
    notebooks/[id]/notes/route.ts              list + create notes
    notes/[id]/route.ts                        patch + delete note
    sources/[id]/route.ts                      get + delete source
    sources/[id]/summary/route.ts              regenerate summary
    audio/[id]/status/route.ts                 poll a job
    audio/[id]/route.ts                        stream the WAV

components/
  SourcesPanel / ChatPanel / StudioPanel
  UploadDialog / SourcePreviewModal / ArtifactModal
  MindMapViewer / QuizViewer / FlashcardsViewer / TimelineViewer
  NotesPanel / KeyboardHelp / Toast / Markdown / Icon

lib/
  db.ts             SQLite + migrations
  store.ts          CRUD for every table
  types.ts          shared types
  chunking.ts       paragraph-aware ~800-char splitter
  embeddings.ts     OpenAI embeddings + cosine top-K
  ingest.ts         chunk + embed + summarize on upload
  summarize.ts      per-source summary + entities
  openai.ts         two-host podcast script (JSON mode)
  kokoro.ts         TTS + per-line timings + WAV encode
  voices.ts         Kokoro voice catalog
  artifacts.ts      prompts + validators for all 7 kinds
  extract.ts        PDF via pdfjs-dist + URL scraper
  youtube.ts        YouTube URL → transcript

Configuration