How can I verify my file is not uploaded?

Open your browser's developer tools (F12), switch to the Network tab, then run a conversion. You will see the page load its conversion engine, but no request carrying your file — because none is made. You can even disconnect from the internet after the page loads and the conversion still works.

What technology converts the files?

WebAssembly (WASM) lets established open-source engines like FFmpeg (video/audio), PDF.js and pdf-lib (PDF), and Transformers.js (AI tools) run directly in your browser at near-native speed.

Are there file size limits?

There is no server limit because there is no server. The practical limit is your device's memory: images and documents of any common size work fine; very large videos (several GB) can exceed what a browser tab can hold.

How It Works — and How to Verify It

Every tool on this site makes the same claim: your file never leaves your device. This page explains how that's possible, and — more importantly — how you can check it yourself instead of taking our word for it.

The technology: WebAssembly

Traditional online converters upload your file to a server, run conversion software there, and send the result back. Modern browsers make the server unnecessary: WebAssembly (WASM) allows real, compiled software to run inside a browser tab at near-native speed. The same open-source engines that power desktop applications run directly on your device:

FFmpeg (via ffmpeg.wasm) — video and audio conversion, trimming, merging, muting, subtitle burning.
PDF.js (Mozilla) and pdf-lib — reading, rendering, and building PDF files.
jsPDF, mammoth, SheetJS (xlsx), JSZip — documents, spreadsheets, and archives.
Transformers.js ONNX models — the AI tools (background removal, OCR, image upscaling) run neural networks locally in your browser.
Browser-native Canvas and File APIs — image resizing, compression, and format conversion.

When you open a tool, your browser downloads the engine (that's the only thing that crosses the network). Your file is then opened locally, converted locally, and saved locally.

Verify it yourself in 30 seconds

Open any tool on this site — say the video trimmer.
Press F12 (or right-click → Inspect) to open your browser's developer tools, and switch to the Network tab.
Drop in a file and run the conversion.
Watch the Network tab: you'll see the page's assets and the conversion engine load — and no request containing your file. Nothing is sent, because there is nowhere to send it to.

For a stronger test: load the tool page, then disconnect from the internet (turn on airplane mode). The conversion still works — proof that no server is involved.

What this means in practice

Nothing to leak. We can't lose, sell, or scan files we never receive. Safe for contracts, ID scans, medical documents, and anything else you wouldn't email to a stranger.
No file size caps or queues. There's no server to protect, so no artificial limits. The practical ceiling is your device's memory — a laptop handles most videos fine; multi-gigabyte files may exceed what a browser tab can hold.
Speed depends on your device. A modern machine converts faster than a round-trip upload/download would take. An older phone will be slower — the honest trade-off of doing the work locally.

Open source credits

These tools stand on established open-source projects: FFmpeg (LGPL/GPL), Mozilla's PDF.js (Apache-2.0), pdf-lib (MIT), jsPDF (MIT), mammoth.js (BSD-2-Clause), SheetJS Community Edition (Apache-2.0), JSZip (MIT/GPL), heic2any (MIT), exifr (MIT), and Hugging Face's Transformers.js (Apache-2.0). We self-host these libraries and are grateful to their maintainers.

Questions? See the privacy policy or about page, or email neuralwork.net@gmail.com.