Hey!
I built Sinsubir because I was tired of uploading my personal files — photos, contracts, IDs — to random websites just to convert or compress them. You never really know where those files end up. So Sinsubir runs 100% in your browser. Your files never touch a server: no uploads, no accounts, no watermarks, no limits. Convert HEIC to JPG, compress images, merge/split/sign/watermark PDFs and more — all processed on your own device, and gone the moment you close the tab. It's free and there's nothing to install. I'd love your feedback on which tool to add next!
The interesting opportunity isn't offering browser-based file conversion—it's eliminating the trust decision users normally have to make before handling sensitive files online. I'd keep validating whether people choose Sinsubir because it's free or because local processing becomes the reason they never consider server-based tools again. That's a much stronger position.