DupeWatch Most advanced Anti-Dupe plugin v1.3.7

You're obliged to contact them after buying because of a license key which is needed to run the plugin. Turning to 3 as they took about three hours

Solid addition to any anti-cheat setup — this plugin isn’t meant to be a one-stop solution, but it pairs really well with other systems. The configuration is straightforward, webhook integration is simple, and overall it’s been a smooth experience to fine-tune. Everything has been working great so far; it just takes some time to dial things in since every server is different. No complaints here — not really sure what the previous reviewer was on about.

This is a review based on a few days of actual use and code analysis shared by the dev through other means; I will try to avoid overly technical details to keep it easy to understand. If you don't want to read the whole comment, I'll say this: this plugin won't keep a server secure on its own, it strictly requires CoreProtect and a preventive anti-dupe. Despite its name saying "Most advanced Anti-Dupe," it doesn't actually prevent any kind of dupe, so any exploit will continue to work.

The plugin is not a preventive system but a reactive counter that acts as an alarm, alerting once the damage has occurred, provided that the duplicated item is on a watch list; however, being on the list does not mean being protected. This means it won't stop any known type of dupe, and the exploit can be bypassed or might not even be registered if entities, shop systems, or other similar methods are used. The promoted unique signature system also fails to differentiate between a dupe and a legitimate item despite performing a bit-by-bit comparison through unique identity tracking; any item with the same NBT will be counted as a potential dupe regardless of the signature, which generates constant false positives making it unreliable for a production environment. For example: when adding a sand block, which should generate a "unique" signature, if you collect more sand (where each block should theoretically have a different signature), it will still trigger a dupe case because it only compares item metadata; in the plugin's eyes, they are identical items, causing false positives for such common cases.
Furthermore, tracking common items like diamonds generates a constant load on the server. The author himself acknowledges performance limitations when tracking high-circulation items, which restricts the plugin's use to very limited economies; this highlights a lack of optimization in the process queue that needs to be improved, since an anti-dupe is purchased to protect the entire economy and not just the items the author deems important.

The confiscator is blind and will delete anything within the threshold; this deletion data is often lost, making it difficult to recover an item even with CoreProtect, as its connection with the plugin is not optimal and it isn't listed as a mandatory dependency despite being necessary for traceability. My first impressions regarding the license were negative because the delivery of the license key is not automated, forcing you to wait for the developer to be active after the purchase to start using the plugin, added to provider failures that prevented initial access; although the developer claims to have fixed it, I criticize the need to verify the license every so often and the lack of a command to attempt re-verification if it fails, as the plugin completely deactivates itself if this occurs, forcing a full server restart.
Not everything is bad; I'll give a point in favor of the interface because it is organized and easy to understand. Uses that I consider could be safe are when you have unique items that you know for a fact should never have duplicates; in that case, the plugin will be efficient since it won't send false positives, and they could only dupe it by separating item collisions through entities or other previously described methods. I believe that as long as they don't know the full mechanics I've described here, the item will be safe; however, I still recommend complementing DupeWatch with a preventive anti-dupe.

The developer offers the option to try the plugin before buying it, which I find excellent and fully recommend; he does this through his Discord by opening a ticket, so you can make sure it's what you're looking for, as this review might age and the plugin could improve, worsen, or change completely, and what really matters is your own experience within your server.

Best anti dupe plugin using it for my server SentrySMP

I can say that the plugin works great; whenever I had a problem with it, the developer was almost always there to help me out. Hats off to him.