The first step to link your thinking. Drop a PDF, Word doc, spreadsheet, email, or screenshot — Thunderegg writes clean .md right next to it. The plain-text format LLMs understand best, and your notes link forever. Nothing uploaded. No account.
AI models are trained on Markdown. Feed them clean .md instead of PDFs and Word files, and you get sharper answers for fewer tokens — while your knowledge stays portable forever.
Markdown strips the formatting bloat of PDF and DOCX. Same meaning, ~30% fewer tokens — lower API costs and more room in the context window.
Headings, lists and tables survive the conversion. That preserved hierarchy is exactly what models use to reason — clearer answers, fewer hallucinations.
Locked in a PDF, a document is a dead end. As .md it becomes a node — wiki-linkable in Obsidian, Notion or any vault, so every file connects to the rest of your thinking instead of sitting in a silo.
Documents, spreadsheets, email and images — all converted to clean, LLM-ready Markdown.
Email becomes a tidy header + body (attachments listed, never dumped as raw code). Screenshots & scans are read with Apple’s on-device Vision OCR.
Whatever fits your flow. The Markdown always lands right next to the original.
Drop one or many files onto the Thunderegg icon in your Dock. Done in seconds — no window, no fuss.
Select any files → Quick Actions → Convert to Markdown. System-wide, no app to open.
Drop files into your MarkItDown Watch folder and they convert automatically — originals tidied away for you.
Most “convert to Markdown” tools upload your documents to a server. For contracts, medical records, financials, or anything under NDA, that’s a non-starter.
Thunderegg does all conversion and OCR on-device, via Apple’s built-in Vision engine. Pull the network cable and conversion still works. (Optional AI enrichment is off until you connect a provider — keep it local to stay fully on-device.)
Everything the online converters do — without the upload, the account, or the per-page meter.
| Feature | Thunderegg | Cloud converters |
|---|---|---|
| Files stay on your Mac | Always | Uploaded |
| Works offline | Yes | No |
| Account required | None | Sign-up |
| Pricing | Free | Per-page / monthly |
| Image OCR | Apple Vision | Varies |
| Email (.eml / .msg) | Clean parse | Rare |
| Output saved next to file | Yes | Download |
No account, no license key, no subscription. Every Mac you own.
Thunderegg is free for everyone, forever — this isn’t a launch discount or a trial. If it earns a place in your workflow, now or down the road, the Founding Supporter tier ($10+, pay what you want, once) keeps development going. It doesn’t unlock anything, because everything is already yours — it’s a thank-you, not a toll. Supporters get named thanks and first access to Thunderegg+ when it ships.
Become a Founding Supporter — $10+report.pdf becomes report.pdf.md. Two files with the same name never overwrite each other.Stop pasting documents into web tools. Keep your files where they belong.
Download Thunderegg — Free