How processing works
All 1FileTool processing runs on your computer using bundled engines like ffmpeg, sharp and pdf-lib — a few AI features download a model once.
1FileTool does its work on your computer, not on a server: the app ships the real processing engines inside the installer, so a convert, compress or redact job runs entirely on your machine. That's why there's no upload wait and no processing queue — the file is read, worked on and written locally.
Protect your originals first
Replace source is ON by default: the output overwrites the original file and no backup is kept. Before following along, open Settings › General and turn Replace source off, or pick a separate output folder.
The engines inside the app
| Engine | Powers |
|---|---|
| ffmpeg / ffprobe | Video and audio compression, conversion, trimming, GIFs (H.264 CRF; WebM uses VP8/Opus) |
| sharp / libvips | Image convert, resize, compress (mozjpeg, WebP, AVIF) |
| heic-convert | Reading iPhone HEIC/HEIF photos — input only, HEIC can't be written |
| pdf-lib + pdfjs-dist | PDF merge, split, edit, render and extraction |
| Tesseract.js | OCR — English only, outputs a .txt file; its language data may download on first use |
| ONNX Runtime | The on-device AI features below |
| archiver, xlsx | ZIP archives and Excel/CSV spreadsheets |
There's intentionally no Ghostscript, qpdf or LibreOffice inside — which is why a few jobs have honest limits, like PDF/A setting metadata only, or PDF compression re-encoding images rather than text.
The on-device AI
The AI engines (Piper for speech, DeepFilterNet for voice cleanup) ship inside the installer. What downloads later are the models:
- Read Aloud / Document to Audiobook voices — about 63 MB each (Ryan High is 121 MB), fetched from Hugging Face the first time you pick a voice.
- Background Removal — a one-time ~178 MB IS-Net model download on first use.
Each download happens once, then works offline forever after.
What a run looks like
Drop files onto a tool (or press ⌘/Ctrl+V to paste them), set options, hit Run. Long jobs move to the background task bar at the bottom-right, where you can keep working or cancel. Every result card shows the size before and after and the percentage saved — including the honest case where a file grew instead of shrank — and History keeps the record of every run.
What needs the network
Processing never does. A short list of features do reach out: update checks (GitHub Releases), license activation (Lemon Squeezy), the one-time model and voice downloads, anonymous usage analytics (on by default, after a consent dialog — disable any time in Settings › Privacy), and AI Chat, which sends whatever your chosen AI CLI reads to that provider. The full list is on Privacy: what leaves your computer.