ModsFinder

Missing Mods Checker

by Txni

Missing Mods Checker, a client-side utility by Txni, opens a Java Swing window listing mods that are absent from a modpack when the game starts.

FabricForgeNeoForgeClient-side onlyCustom license1.20 – 1.21.1

What it does

When a modpack is missing mods, the checker shows a simple window listing them at startup. A player can select an entry to open its link, set in the config file, in a browser, or use a button that opens the mods folder. The checker runs on the client alone, so a server does not need it.

The modpack author controls the list through a missing mods checker JSON file in the modpack's config folder, where entries are added for each mod. Filenames can be matched with regular expressions, and exact versions can be enforced so that accidental updates by end users are caught. The mod requires Fabric API and TxniLib. It is published for Fabric, Forge and NeoForge, with files for 1.20.1 and 1.21.1, under a custom license that is not open source.

Key features

  1. Startup prompt for missing mods

    On launch, a window lists required or optional mods that are not present, so players see gaps before playing.

  2. Protection of core mods

    Important mods are flagged so they cannot be quietly removed or swapped out, and the checker reports when that happens.

  3. Exact version enforcement

    Pinned versions are checked against the installed files, which blocks an update a player applies by mistake.

  4. Optional mods on first launch

    Optional mods can be offered the first time the game starts, letting players opt in during setup.

Compatibility

Latest build for each game version and loader.

1.21.1fabric-1.21.1-1.0.1Not availableneoforge-1.21.1-1.0.1
1.20.1fabric-1.20.1-1.0.1forge-1.20.1-1.0.1Not available
1.20fabric-1.20.1-1.0.1forge-1.20.1-1.0.1Not available
ReleaseBetaAlphaNot available

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

Requirements

Dependencies declared by the latest file for each loader.

Required 2

TxniLibMultiversion library mod for Txni projects
Required
Fabric APILightweight and modular API providing common hooks and intercompatibility measures utilized by mods using the Fabric toolchain.
Required

How it compares

Full comparison

Mod Checker Reworked is open source under the MIT License, client-side only, and published for 1.20.1 – 1.21.11 on Fabric, Forge and NeoForge. Modpack Update Checker is not open source, licensed under Creative Commons Attribution Non Commercial No Derivatives 4.0, and runs on either side, where neither side needs it, across 1.16.5 – 1.21.6 with Quilt added. Simple Update Checker is open source under the GNU Lesser General Public License v3.0 only, runs on either side where neither side needs it, and targets Fabric and Quilt for 1.21.1 – 26.3.

ModLoadersGame versionsEnvironmentUpdated
Missing Mods CheckerFabric, Forge and NeoForge1.20 – 1.21.1Client-side only2026-02-28
Mod Checker ReworkedFabric, Forge and NeoForge1.20.1 – 1.21.11Client-side only2026-01-02
Modpack Update CheckerFabric, Forge, NeoForge and Quilt1.16.5 – 1.21.6Client or server, optional2025-06-22
Simple Update CheckerFabric and Quilt1.21.1 – 26.3Client or server, optional2026-09-11

Questions

Does Missing Mods Checker need Fabric API on every loader?

Fabric API is required, and TxniLib is required as well. Both must be installed alongside Missing Mods Checker.

Does a server need Missing Mods Checker installed?

No. Servers do not need it; each player installs it for their own game.

How does a modpack author add mods to the checker list?

The author edits the missing mods checker JSON file in the modpack's config folder and adds an entry for each mod, with regular expressions or exact versions.

More from Txni

All projects
Sodium Options API1.20 – 1.21.5Sodium Dynamic Lights1.20 – 1.21.5TxniLib1.20 – 1.21.5Sodium Extras1.20 – 1.21.5Sodium Leaf Culling1.21.1Sodium Options Mod Compat1.20 – 1.21.4

What the author says

Whatever the reason mods are found to be missing, the mod will open up a simple Java Swing window with a list of all missing mods. The user can click "download," which will open the link specified in the config file in their browser. To make things easier, there is a button that opens the mods folder directly. You…
Txni, on the Modrinth page

Official listing

Owner
Txni
Published
2026-02-17
Updated on Modrinth
2026-02-28
Facts verified
2026-10-15
Open on ModrinthCompare