I built a file-tools site where devtools can prove nothing gets uploaded

CodeCreatorManMike — Mon, 24 Aug 2026 11:13:10 +0000

The problem: "free" converter sites that quietly upload your files

Every time I needed to merge a PDF, strip the GPS data out of a photo, or convert some HEIC files my phone had dumped on me, the options online all worked the same way: pick a file, upload it to someone's server, wait, download the result.

That's fine for a lot of files. It's not fine for a scanned ID document, a photo that still has your home address baked into its EXIF data, or a work file you're not actually supposed to be putting on a random third-party server in the first place. And most of these sites don't hide it — they'll tell you "we delete your file after 24 hours" or "we don't store your data long-term," which is a nice policy, but it isn't the same claim as we never had it. One is a promise about server-side behavior you have to trust. The other is just... not sending the file anywhere.

I kept running into this same annoyance across completely different file types — PDFs, images, audio, CSVs — often enough that it stopped feeling like a one-off inconvenience and started feeling like a pattern worth actually fixing. So I built Kit-Bin: a set of file tools that don't have that problem, because the file never leaves your browser.

What Kit-Bin does differently — and how to verify it yourself

The short version: every tool runs entirely client-side, in JavaScript/WASM, in your browser tab. There's no upload step, because there's no server on the other end doing the processing. No accounts, no file size gated behind a paywall, no "sign up to download your result."

I'm not asking you to take that on faith, though — that's the whole point. Open your browser's devtools, go to the Network tab, and use any tool on the site (merge a PDF, strip metadata from an image, whatever). Watch the network requests while it processes. You'll see the page's own static assets load once, and then nothing — no request carrying your file data goes out while it's being processed. That's the actual proof, not a claim on a privacy policy page you have to trust me on.

This is also why the project is fully open source. If you don't want to just check the network tab, you can read the code that's doing the processing and confirm it yourself: github.com/CodeCreatorManMike/Kit-Bin.

What's actually in it

Kit-Bin is organized into six categories, all following the same client-side-only rule:

PDF tools — merge, split, compress, delete/extract pages, add page numbers, remove metadata, sign, and more.
Image tools — rotate, resize without distorting, remove EXIF/GPS data, extract a color palette as hex codes, convert between HEIC/AVIF/WebP/PNG/JPG, remove backgrounds.
Audio tools — normalize volume/loudness, convert between formats (MP3/WAV), text-to-speech, transcription.
Video tools — compress, trim, mute, reverse, convert to MP4, make a GIF, boomerang effect.
Data tools — CSV cleaning and merging, Excel-to-CSV/JSON conversion, JSON formatting and diffing.
Developer tools — SHA-256 hashing, Base64 encoding, UUID generation, QR code generation/scanning, JSON schema validation, password generation.

Alongside the tools, there's a growing set of plain-language guides explaining the why behind a lot of these — things like why your PDF is so big, why your iPhone photos won't open on Windows, or what a SHA-256 hash actually proves. I wanted the site to be useful even when you're not actively running a file through it.

It's open source — feedback and contributions welcome

Kit-Bin is a side project I build in the evenings and weekends around a full-time technical analyst role, so it's very much still growing. If you try it and something's confusing, broken, or missing a tool you'd actually want, I'd genuinely like to hear about it — either as a comment here, an issue on GitHub, or a PR if you want to dig in directly:

Site: kit-bin.com
Repo: github.com/CodeCreatorManMike/Kit-Bin

If you care about the same thing I do here — tools that are private because of how they're built, not because of a policy that says so — I'd appreciate you giving it a try and telling me where it falls short.

DEV Community: CodeCreatorManMike

I built a file-tools site where devtools can prove nothing gets uploaded