10 MB · .pdf or .docx.How it works
1. Text extraction (in your browser) — PDFs are parsed by Mozilla's pdf.js; .docx files by mammoth.js. Both run locally — the file binary never leaves your device.
2. Summary (in the cloud) — only the extracted text is sent to ClassMinds' servers, then to OpenAI for summarization. The text and the summary are not stored on our servers.
3. Limits — 3 summaries per day per IP address. Max input size 10 MB. PDFs cap at 60 pages; long files auto-truncate to the first 25,000 characters. Scanned PDFs (image-only) and image-only Word docs won't work — we need actual text.
Privacy — we don't log the PDF text or its summary. Standard request logs (IP, timestamp, status) are kept for ~7 days for abuse prevention. We don't sell or share anything.
Cost — this is genuinely free. No watermark, no sign-up wall, no "upgrade for unlimited." If 3/day isn't enough, the iOS app gives you unlimited grounded summaries.
Want unlimited summaries that remember your class context?
The iOS app summarizes lectures, slide decks, and PDFs — and the AI tutor remembers all of it across the semester. Free during beta.