This is a small online tool where you can “upload” multiple gifs to concatinate all gifs to one (no drag & drop, just select one after another).
The cool thing: nothing is uploaded to a server, everything is handled right in your browser! If you want to have a look in the network debugger: all requests are intercepted and answered “from ServiceWorker”
Please find more infos on the github repo: https://github.com/cdreier/wasmachine
Please note: This is just a demo! (and i think the “reverse” flag is bugged most of the time)