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FastFileTool
Edit, convert & compress files 100% locally. Zero uploads.
13 followers
Edit, convert & compress files 100% locally. Zero uploads.
13 followers
FastFileTool is a privacy-first web utility suite that converts, compresses, and edits PDFs, videos, images, and audio entirely inside your browser. Powered by WebAssembly and client-side scripts, your sensitive data never leaves your computer. No network wait times, no storage server file intercepting, and a radically reduced carbon footprint. Work offline, securely, and with zero file-size limits.
love that everything stays local, huge plus for handling sensitive docs. one thing that would make it even better for me is a batch watermark tool for pdfs, like letting me drop a folder, pick a text or image stamp, position and opacity, then export the whole set in one go. right now i have to watermark files one at a time and it kills the workflow when im prepping a stack of contracts.
@soneragah57306 Thanks for the feedback, Soner Agah!
You're absolutely right, batch watermarking would be a huge improvement for workflows involving lots of documents. Being able to drop a folder, apply a text or image watermark with custom position and opacity, then export everything at once is exactly the kind of feature we want to add.
We'll be working on adding this soon. Thanks for sharing your workflow and helping us improve FastFileTool!
@soneragah57306 Hey Soner, it’s live!
I just finished building and deploying the exact feature you requested. You can now drag and drop multiple PDFs at once, customize your watermark (text, logo image, or even a hand-drawn signature), adjust size, opacity, and rotation, and then export the whole stack in one click as a single ZIP file. And just like everything else on FastFileTool, it all runs 100% locally in your browser so your contracts stay completely private.
Give it a spin here: https://fastfiletool.fr/en/tools/pdf/batch-pdf-watermark/
Let me know how it works for your workflow!
How does it actually handle the really compute-heavy stuff like compressing a long video without melting my laptop, is there a size cap that kicks in even though it says zero file-size limits?
@glhan1kol Thanks for the question, Gülhan!
FastFileTool processes everything directly in your browser using your device's own resources, so your files never leave your computer.
For heavy tasks like compressing long videos, the experience mainly depends on your hardware (CPU, RAM) and browser capabilities. We don't impose an artificial file-size limit, but very large files can naturally be affected by available memory and processing power.
We're also working on improving the experience for large files with better progress tracking and performance optimizations.
Curious how you handle really large video files in-browser without choking on memory, is there a chunking trick under the hood or do you just lean on each browser's available RAM?
@ferhat148502 Hey Ferhat!
We don't do traditional chunking. Instead, we process files one by one rather than in parallel to avoid peaking the browser's available RAM. Since we run FFmpeg via WebAssembly, we write the imported video directly into WASM's virtual file system (MEMFS). The second the output blob is generated, we immediately trigger a manual file deletion using ffmpeg.deleteFile().
By unlinking the source and output buffers from the WebAssembly layer the millisecond a task finishes, we force JavaScript's Garbage Collection to reclaim that RAM before the next file begins. This routine keeps the app rock-solid and leak-free even during heavy batch workloads.
Let me know if you want to geek out more on this!
Finally something that handles big video files without uploading them anywhere, compressed a 4K clip in under a minute right in my browser. The offline-first approach is a nice change from all these tools that farm out your files to random servers.
@acsefa73688 Thanks for sharing your experience, Sefa Acıbadem!
We're really glad to hear that FastFileTool worked well for your 4K video. Keeping processing local was one of our main goals — your files stay on your device instead of being uploaded to external servers.
We believe privacy and performance can go together, and we're continuing to improve the experience for larger files and more demanding workflows. Thanks for trying FastFileTool!
How does the WebAssembly side actually handle large video compression without choking on RAM on older laptops?
@ayseluzerer6pg Hi Aysel, it works by utilizing WebAssembly to perform processing directly on your machine's CPU, rather than on a remote server. It handles large files by using streaming and chunk-based processing, which means it manages data in small segments to avoid overloading your RAM, keeping performance stable even on older laptops.
Have you noticed any performance differences depending on the video format you are using?