I've been using it without problems for many years. About 3-4 months ago, scripts started to be deleted when syncing, I was shocked! I added several accounts to save the scripts, and noticed that after a while many of the scripts disappeared.
It's good that I had a backup, because I have almost 200 scripts (but half are disabled now). And so it would be... It would be a disaster to lose everything over the years. In short, after synchronization, the program deleted most of the scripts and left 20-30 pieces. I figured out how to delete the sync and saved it manually.
Now, about 2 months ago, new problems started. Scripts stopped working on different sites, from YouTube to others. And most importantly, you don't even think about it. I noticed that the functionality on YouTube is missing. And only then did I notice that the script manager had fallen off there and was no longer working on YouTube, the icon was not glowing on YouTube.
Now new problems have begun. And I also didn't think about the script manager, but I thought about the scripts themselves, that they didn't work. But it turned out to be him.
I turned on Tampermonkey and everything worked. Before the latest updates, everything worked fine for years, so you don't even think about the script manager.

// @grant GM_xmlhttpRequest working FLAWLESS!!!

klappt alles super

Macht was es soll. Nur das Unterlegen / Hervorheben von Suchbegriffen könnte deutlicher sein. In den meisten Themes sieht man nicht viel. Man muss schon genau hinsehen, um alle Suchbegriffe auf einen Blick zu sehen. Das ist anstrengend.
Am besten diesen Punkt separat einstellbar machen. Nicht jeder hat top 100%ige Augen...

The best userscript manager for Firefox.

I used Greasemonkey forever, then switched to Tampermonkey after Firefox broke legacy support with its multi-process architecture. I still run both, but Violentmonkey outperforms its competitors in every way that matters.

No bloat, privacy-focused, actually optimised for Firefox and open-source. Tampermonkey being closed-source, and originally Chrome-centric (pre-Manifest V3). If you're using Firefox, use Violentmonkey.

Best open source userscript manager I've tried, it works well for my needs.

Violentmonkey is a great extension for anyone who wants to run userscripts in their browser. It’s open source, easy to use, and lets you customize websites with extra features or tweaks. Installing and managing scripts is simple, and it works smoothly without slowing down browsing. Perfect for users who like to personalize and enhance their web experience.

Incredibly useful; browser is unusable without this amazing tool.