ModsFinder

RequiredMods

by BluDood

RequiredMods lets a server control which mods connecting players may run, using allow, deny or strict rules set in its config.

FabricClient and serverMIT LicenseOpen source1.21.1

What it does

The mod checks the mods a player has installed when that player joins a server. A server owner can set a mode of ALLOW, DENY or STRICT, and list mods in the allowMods or denyMods options. In ALLOW mode only the listed mods are accepted, in DENY mode the listed mods are refused, and STRICT requires the listed mods to be present. A player who fails the check is turned away with a message naming the missing or denied mods, so the rule is explained at the point of refusal.

RequiredMods is installed on the server and on every client that connects to it, and the enabled option switches the check on or off. Operators can read a player's mod list with commands, which helps when a rule needs checking. The mod is published for Fabric only, and its single build targets 1.21.1 and is released under the MIT License, with the source code and issue tracker available as public links.

Key features

  1. Allow and deny lists

    The allowMods and denyMods options take lists of mod IDs that the server accepts or refuses.

  2. Strict mode

    In STRICT mode the listed mods must be present, so a connection without them is refused.

  3. Denial message

    A refused player sees a message naming the mods that were missing or denied.

  4. Player mod commands

    Commands let an operator see which mods a given player has installed.

  5. Enable switch

    A boolean option turns the whole check on or off without removing the configured lists.

Compatibility

Latest build for each game version and loader.

1.21.11.0
ReleaseBetaAlphaNot available

Only full game releases are shown. This mod publishes no snapshot builds.

Use cases

Private servers

A server owner can require a particular client mod so that players share the same set of features.

Blocking unwanted mods

A server can list mods it does not want and refuse players who run them.

Who it’s for: Server owners who want to control the mod set their players connect with, and modpack authors who need players to run a specific set of mods.

Questions

Does RequiredMods have to be installed on clients?

Yes. Servers that run it need every player to install it too.

What is the difference between ALLOW and DENY mode?

In ALLOW mode only the mods listed in allowMods are accepted. In DENY mode the mods in denyMods are refused and everything else is accepted.

Which loader does RequiredMods run on?

The mod is published for Fabric only, with a single file for 1.21.1.

In the catalog

RequiredMods is one of 8,499 Technology mods on ModsFinder, and one of 4,201 Technology mods for Fabric. 32,366 mods support Minecraft 1.21.1.

Technology mods8,499Fabric modsMods for 1.21.132,366

Similar mods

Create Big Cannons1.18.2 – 1.21.1GD656Killicon1.18.2 – 1.21.4Fabric Seasons: Extras1.19.2 – 1.21.1Ad Astra1.18.2 – 1.21.1Create: New Age1.19.2 – 1.21.1CC: Tweaked1.4.7 – 26.3

What the author says

RequiredMods on the server will by default only check if clients has RequiredMods installed, but this can be configured to allow players without the mod too. The server configuration file can be found in config/requiredmods.json. The client does not have any configuration.
BluDood, on the Modrinth page

Official listing

Owner
BluDood
Published
2025-04-24
Updated on Modrinth
2025-04-24
Facts verified
2026-10-15

Tags

ManagementTechnologyUtility
Open on ModrinthCompare