How to Convert Files Without Uploading Them
Most online converters upload your file to their servers. Filembly's Local Mode runs supported conversions and PDF tools entirely in your browser — the file never leaves your device, there is no upload wait, and the usual server size limits don't apply.
The problem with uploading files to convert them
A classic online converter works by sending your file to a server, converting it there, and sending the result back. That model has three costs: your document travels to someone else's computer (a privacy question you can't verify), the round trip takes as long as your connection allows, and the service must cap file sizes to protect its servers.
For sensitive files — contracts, IDs, medical records — the honest answer to "is it safe to upload this to a converter site?" is: you are trusting a stranger's retention policy.
Local Mode: conversion inside your browser
Modern browsers can do real file processing themselves. Filembly's Local Mode uses that: for supported operations, the conversion runs as code on your own device, and the file is never transmitted at all — not stored, not uploaded, not even sent.
You don't have to configure anything. When an operation can run locally in your browser, the converter shows a lock note — "Runs on your device — your file is never uploaded" — and simply does the work on the spot. If a browser lacks a capability, Filembly falls back to its usual in-memory server processing, which still stores nothing.
What runs locally today
Because no server is involved, these operations accept files up to 50 MB — far beyond the 4 MB limit that applies to server-processed conversions — and they work even on a slow connection, since there is nothing to upload.
- Image conversions between JPG, PNG and WEBP
- JPG or PNG to PDF
- Merge PDF, split PDF and remove PDF pages
- Compress image (JPEG/WEBP) and resize image
How to use it
- Open any supported converter or tool on Filembly.
- Look for the lock note under the options — it confirms this operation runs on your device.
- Add your file and convert. There is no upload step: processing starts immediately.
- Download the result. Nothing was transmitted at any point.
Local Mode vs. "we delete your files" promises
Most converter sites promise to delete uploads after an hour or a day. That is a policy — you can't verify it, and the file still made the trip. Local processing is a stronger guarantee by construction: there is nothing to delete because nothing was ever sent. For the operations Local Mode covers, the privacy question disappears entirely.
Document conversions that need heavier engines (PDF to Word, Excel to CSV) still run on Filembly's servers — in memory, never written to disk, never retained. Every page states which model applies, so you always know where your file went: usually, nowhere.