Show HN: ThinkTotem – turn boring books into engaging conversations
What it does
- Ingests PDFs, EPUBs, Word docs, plain-text URLs and even YouTube transcripts (≤ 4 MB for now)
- Maps key ideas, trims filler and surfaces the essential concepts automatically
- Runs an active-recall loop: Socratic questions, explain-it-back prompts, spaced-repetition style refreshers
- Tracks mastery so you can skip, revisit or move on
Why not just use ChatGPT/Claude?
- General LLM chat is open-ended: you have to decide what to ask next.
- ThinkTotem is purpose-built for reading: short conversational loops keep attention, progress is visible, and the questions are sequenced to test retention rather than entertain.
How it works under the hood
- Document is paraphrased, chunked, metadata, summaries and questions are created, and stored in Postgres
- Every chat turn includes in the context the most relevant part of the current chapter, the summary of the book and the last messages (no vectorisation of the content needed)
- A small policy model classifies each turn (summary vs. question vs. recall) so the chat stays focused.
- A spaced-repetition scheduler writes “due” concepts back into the queue and surfaces them at the right time.
- User voice is transformed into text and LLM generated text is transformed into speech with OpenAI TTS/STT models
- All LLM logic runs server-side (Next.js app); the front end is Next.js with React Server Components.
Pricing / openness
There’s a free tier (3 uploads, 1 h chat, 50 messages) plus paid plans that just scale limits-no feature gating.
Costs
- Ingestion (Gemini Flash): ~30 s per 300-page PDF, $0.05–$0.10.
- Conversation (OpenAI TTS): ≈$0.40 per user-hour. Nothing is optimised yet; these two items dominate my bill.
Privacy
I delete originals after processing, just derivative work of it gets stored (e.g. summaries). I never feed your documents into model training and you can purge processed content at any time.
What’s missing / known issues
- 4 MB per-file cap-larger uploads are on the roadmap
- No org accounts yet; “Ultra” plan lets teams share a single login until then
- Conversation UX on mobile is still not state of the art (mobile Safari disables audio/mic when not in use for a few seconds, so UX is limited)
Ask
- Does the active-recall flow feel helpful or annoying?
- What would you need in the product to become a daily user?
Live demo
The app is live at https://thinktotem.com (no credit card needed).
I’ll be online all day-happy to answer anything, share infra costs (TTS is crazy expensive), or dive into the ingestion process.
Thanks for reading, -Claudio (solo maker, UTC+1)
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