Vault Patcher
by 3093FengMing
With Vault Patcher installed, hard coded strings in other mods can be replaced by localization strings through simple JSON files.
What it does
Vault Patcher is a library that lets players alter fixed text inside other mods by writing JSON rules. The changes are meant to help translators localize content that would otherwise stay in one language. Players write the replacement rules in configuration files, and the library applies them to the target mod's classes.
The mod works through bytecode modification. It uses ASM to swap out the affected classes, and it keeps a cache that is rebuilt only after a target mod updates, so the cost on modern hardware is described by the author as not significant. The author states that the mod requires players to write their own customization content; the file format and operating details are documented on the project wiki.
Vault Patcher is a Client and server mod, so the server and every player need it. It is released under the GNU General Public License v3.0 only and is open source, with a public source code repository and issue tracker. Builds are published for Fabric, Forge, NeoForge and Quilt, with 86 release versions covering 1.6.1 – 26.2.
Key features
JSON string replacement
Hard coded text in other mods can be changed or overwritten by writing JSON rules instead of editing code.
Localization support
Replacement strings let translators supply localized text for mods whose strings are otherwise fixed.
ASM class replacement
Affected classes are swapped at load time with ASM, and cached results are reused until the target mod changes.
Cache rebuilt on update
The cache is refreshed only after a target mod is updated, which keeps repeated start-ups quick.
Compatibility
Latest build for each game version and loader.
26.x4 of 4 versions with builds
1.21.x12 of 12 versions with builds
1.20.x7 of 7 versions with builds
1.19.x5 of 5 versions with builds
1.18.x3 of 3 versions with builds
1.17.x2 of 2 versions with builds
1.16.x6 of 6 versions with builds
1.15.x3 of 3 versions with builds
1.14.x5 of 5 versions with builds
1.13.x1 of 1 version with builds
Only full game releases are shown. This mod publishes no snapshot builds.
38 older game versions (1.6.1 – 1.13.1) not shown. All files on Modrinth
Use cases
Translating mod text
A translator writes JSON files that map the English strings of a mod to another language.
Customizing wording
A player rewrites labels or messages in a modpack to match a different style without changing the original mod.
Who it’s for: Modpack makers, translators and players who want to change the text of installed mods. The mod is a library, so it is most useful alongside the mods whose strings it targets.
Questions
Does Vault Patcher have to be installed on both sides?
Which loaders does Vault Patcher support?
Where are the JSON file formats documented?
In the catalog
Vault Patcher is one of 3,514 Library mods on ModsFinder, and one of 2,348 Library mods for Fabric. 13,894 mods support Minecraft 26.2.
More from 3093FengMing
Similar mods
What the author says
This is an library mod that requires players to customize content. It allows players to use simple JSON syntax to change or overwrite hard coded text in other mods that helping translators with translation.
Official listing
- Modrinth page
- modrinth.com/mod/vault-patcher
- Owner
- 3093FengMing
- Published
- 2022-12-23
- Updated on Modrinth
- 2026-08-18
- Facts verified
- 2026-10-15