JRSecurity
by Jaxroxn
JRSecurity checks the mod list a Fabric client sends to a server right after joining, so server owners can see which mods are installed.
What it does
After a player joins a server running the JRSecurity plugin, the Fabric client sends its installed mod list to the server through the Payload API that Mojang added in 1.20.5. The transmission is built to work alongside vanilla networking, and the list is cleaned and sorted before it is sent. Mod entries are separated from libraries and APIs, so the list is easier to read.
The mod has two parts: a client mod placed in the mods folder, and a server plugin for Paper, Spigot or Bukkit. The server side enforces a blacklist from config.yml, matching either exact mod IDs or substrings. Players who match a blacklisted entry are kicked with a message the owner can customize, and each join is written to plugins/JRSecurity/joinlogs.
The client needs Fabric Loader and Fabric API installed, and Java 17 or newer is recommended. The mod is published for Fabric only, across 18 release versions 1.20.5 – 26.2, with Mod(Client)-1.3 for 26.1.1 as the latest Fabric file. The server plugin runs on Paper, Spigot and Bukkit. The code is not open source, and the license is All rights reserved.
Key features
Automatic mod list handshake
The client sends its installed mod list to the server automatically after a successful join.
Blacklist enforcement
Blocked mods are listed by exact ID or substring in config.yml, and matching players are removed.
Custom kick message
The message shown to a removed player can be changed in the configuration file.
Per-join logs
Each join is logged to plugins/JRSecurity/joinlogs with the cleaned, sorted mod list.
Relevant mods separated from libraries
The list groups gameplay mods apart from libraries and APIs, so the relevant entries stand out.
Compatibility
Latest build for each game version and loader.
26.x2 of 2 versions with builds
1.21.x12 of 12 versions with builds
1.20.x2 of 2 versions with builds
Only full game releases are shown. This mod publishes no snapshot builds.
How it compares
FailureToLog api is a Fabric library for 26.1 – 26.2, licensed under CC0 1.0 Universal and open source; it is not a server-side blacklist tool. KillC is a Fabric mod for 1.20 – 26.3 under the Creative Commons Attribution Share Alike 4.0 license and is not open source. DSwhitelist is open source under the Apache License 2.0 and covers Fabric and Forge 1.16 – 1.21.1, so it fits servers on older game versions.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| JRSecurity | Fabric | 1.20.5 – 26.2 | Not published | 2026-04-04 |
| FailureToLog api | Fabric | 26.1 – 26.2 | Client or server, optional | 2026-07-04 |
| KillC | Fabric | 1.20 – 26.3 | Not published | 2026-09-16 |
| DSwhitelist | Fabric and Forge | 1.16 – 1.21.1 | Not published | 2026-01-09 |
Questions
Does a player need JRSecurity installed on the client?
Which server platforms does JRSecurity support?
Does Fabric API need to be installed?
In the catalog
JRSecurity is one of 8,499 Technology mods on ModsFinder, and one of 4,201 Technology mods for Fabric. 13,894 mods support Minecraft 26.2.
More from Jaxroxn
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What the author says
It requires Client Mod (Fabric) and Server Plugin (Spighot, Paper, Bukkit)! Blacklist enforcement via config.yml (exact IDs + substring contains); violators are kicked with a customizable message Per‑join logs in plugins/JRSecurity/joinlogs/… (cleaned, sorted lists) Smart separation of “relevant mods” vs…
Official listing
- Modrinth page
- modrinth.com/mod/jrsecurity
- Owner
- Jaxroxn
- Published
- 2026-02-17
- Updated on Modrinth
- 2026-04-04
- Facts verified
- 2026-10-15