MultiLogin Compat Mod

⭐ — (1 endorsements) 📥 268 downloads 📌 v1.0.1 📅 3/31/2026
🟡 Updated this year

By wifi-left · fabric

⬇ Download Mod Source: Modrinth 📅 Updated: 4/1/2026 📅 Created: 3/31/2026
⚠️ Install Order · 2 steps
1🛠️ Forge — Minecraft Forge (mod loader) Download ↗
2🛠️ Fabric — Fabric Loader Download ↗

Install in this order, then this mod last — most mods fail to load without their framework and dependencies in place.

🔍 Analysis

  • 🏆 #461 of 909 fabric mods in this game by downloads

📋 About This Mod

✅ On every player login the mod calls the configured MC-MultiLogin-service endpoint with
✅ `detail=true`, so authentication failures return a structured JSON error instead of the
✅ generic "Failed to verify username!" message.
✅ Detailed error reasons (`DUPLICATE_NAME`, `BANNED`, `NOT_FOUND`, …) are forwarded directly
✅ to the connecting client in the disconnect screen.
✅ name is already taken by another skin-site account, the mod automatically retries the login

# mc-multilogin-compat-mod A Fabric server-side mod for Minecraft **1.21.1** (Mojang mappings) that integrates with (https://github.com/wifi-left/MC-MultiLogin-service). 一个用于 Minecraft 1.21.1(Mojang 映射表)的 Fabric 服务端模组,用于与 (https://github.com/wifi-left/MC-MultiLogin-service) 集成,可以实现多源登录方式。 We suggest you to use this with (https://github.com/yushijinhun/authlib-injector/). This mod only change the login method and the login-failed message. 建议配合 (https://github.com/yushijinhun/authlib-injector/) 使用。此模组仅修改登录方式和登录失败时的提示信息。如果您使用`Authlib-Injector`,请记得设定它的链接为 `MC-MultiLogin-service`提供的API地址。 ## Velocity Plugin Version Config can be found at `plugins\multilogin-auth-compat\multilogin-compat-config.json`. 配置可以在`plugins\multilogin-auth-compat\multilogin-compat-config.json`找到。 ## Fabric Mod Version ### Features - On every player login the mod calls the configured MC-MultiLogin-service endpoint with `detail=true`, so authentication failures return a structured JSON error instead of the generic "Failed to verify username!" message. - Detailed error reasons (`DUPLICATE_NAME`, `BANNED`, `NOT_FOUND`, …) are forwarded directly to the connecting client in the disconnect screen. - **Auto-rename on `DUPLICATE_NAME`** (configurable): when the service reports that a player name is already taken by another skin-site account, the mod automatically retries the login with the service-suggested `availableId` (e.g. `Steve_2`) and records the original → new-name mapping in `config/mc-multilogin-renames.json`. ### Setup 1. Place the mod JAR in your server's `mods/` directory. 2. Start the server once – a default config file will be generated at `config/mc-multilogin-compat.json` and the server will **stop with an error** asking you to fill in the API URL. 3. Edit the config and set `apiUrl` to the base URL of your MC-MultiLogin-service method entry (e.g. `http://127.0.0.1:25600/login/my`). 4. Restart the server. ## Configuration (`config/mc-multilogin-compat.json`) ```json { "apiUrl": "http://127.0.0.1:25600/login/my", "autoRename": true } ``` | Field | Type | Default | Description | |-------------|---------|---------|-------------| | `apiUrl` | string | `""` | **Required.** Base URL of the MC-MultiLogin-service login method (e.g. the path configured under `method.url`). The mod appends `/session/minecraft/hasJoined?…` automatically. | | `autoRename`| boolean | `true` | (Not working at present) When `true`, a `DUPLICATE_NAME` rejection triggers an automatic retry using the `availableId` returned by the service. The rename is persisted in `config/mc-multilogin-renames.json`. Set to `false` to disable and show the error instead. | ### Building ```bash # Requires Java 21 and internet access to maven.fabricmc.net ./gradlew build ``` The output JAR will be in `build/libs/`.

# mc-multilogin-compat-mod

A Fabric server-side mod for Minecraft 1. 21. 1 (Mojang mappings) that integrates with (https://github.com/wifi-left/MC-MultiLogin-service).

一个用于 Minecraft 1. 21. 1(Mojang 映射表)的 Fabric 服务端模组,用于与 (https://github.com/wifi-left/MC-MultiLogin-service) 集成,可以实现多源登录方式。

We suggest you to use this with (https://github.com/yushijinhun/authlib-injector/). This mod only change the login method and the login-failed message.

建议配合 (https://github.com/yushijinhun/authlib-injector/) 使用。此模组仅修改登录方式和登录失败时的提示信息。如果您使用`Authlib-Injector`,请记得设定它的链接为 `MC-MultiLogin-service`提供的API地址。

## Velocity Plugin Version Config can be found at `plugins\multilogin-auth-compat\multilogin-compat-config.json`.

配置可以在`plugins\multilogin-auth-compat\multilogin-compat-config.json`找到。

## Fabric Mod Version ### Features

  • On every player login the mod calls the configured MC-MultiLogin-service endpoint with
  • `detail=true`, so authentication failures return a structured JSON error instead of the
  • generic "Failed to verify username!" message.
  • Detailed error reasons (`DUPLICATE_NAME`, `BANNED`, `NOT_FOUND`, …) are forwarded directly
  • to the connecting client in the disconnect screen.
  • Auto-rename on `DUPLICATE_NAME` (configurable): when the service reports that a player
  • name is already taken by another skin-site account, the mod automatically retries the login
  • with the service-suggested `availableId` (e.g. `Steve_2`) and records the
  • original → new-name mapping in `config/mc-multilogin-renames.json`.

1. Place the mod JAR in your server's `mods/` directory. 2. Start the server once – a default config file will be generated at `config/mc-multilogin-compat.json` and the server will stop with an error asking you to fill in the API URL. 3. Edit the config and set `apiUrl` to the base URL of your MC-MultiLogin-service method entry (e.g. `http://127. 0. 0. 1:25600/login/my`). 4. Restart the server.

## Configuration (`config/mc-multilogin-compat.json`)

```json { "apiUrl": "http://127. 0. 0. 1:25600/login/my", "autoRename": true } ```

| Field | Type | Default | Description | |-------------|---------|---------|-------------| | `apiUrl` | string | `""` | Required. Base URL of the MC-MultiLogin-service login method (e.g. the path configured under `method[].url`). The mod appends `/session/minecraft/hasJoined?…` automatically. | | `autoRename`| boolean | `true` | (Not working at present) When `true`, a `DUPLICATE_NAME` rejection triggers an automatic retry using the `availableId` returned by the service. The rename is persisted in `config/mc-multilogin-renames.json`. Set to `false` to disable and show the error instead. |

### Building

```bash # Requires Java 21 and internet access to maven.fabricmc.net ./gradlew build ```

The output JAR will be in `build/libs/`.

🤖 AI-enhanced — based on mod data

📊 Mod Details

Game
Minecraft Mods
Author
wifi-left
Version
1.0.1
Downloads
268
Endorsements
1
Category
fabric
Created
3/31/2026
Updated
4/1/2026
Game Versions
1.16, 1.16.1, 1.16.2, 1.16.3, 1.16.4
Tags
management, utility

🔧 How to Install Minecraft Mods Mods

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❓ Frequently Asked Questions

Which Minecraft Mods versions does MultiLogin Compat Mod support?

The author lists 1.16, 1.16.1, 1.16.2, 1.16.3, 1.16.4, 1.16.5. Other versions may work but are untested by the author.

What is the latest version of MultiLogin Compat Mod?

Version 1.0.1, published 2026-04-01 with 268 downloads recorded at the source.

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