AuthBack
🟡 Updated this year⚠️ Install Order · 2 steps
Install in this order, then this mod last — most mods fail to load without their framework and dependencies in place.
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🔍 Analysis
- 👍 0.7% endorsement rate
- 🏆 #566 of 896 fabric mods in this game by downloads
📋 About This Mod
Allows you to play as normal even when Mojang's authentication servers are down. Additionally also improves the networking behavior.
#### How does it work?
1. The responses from Mojang's webservices/API are cached locally for some time.
If an outage occurs the previously cached responses are used.
For example this allows for your skin to be displayed properly. 2. Every client locally stores (or generates if not present) a keypair, which will be used as a fallback to authenticate with servers when Mojang's authentication servers are down (see (https://en.wikipedia.org/wiki/Public-key_cryptography)).
Please note: The server also needs to have the mod installed You must have already joined the server once (during the past 36 days)
The mod is optional for the client and server.
However if one side lacks the mod joining a server will be impossible when Mojang's authentication servers/APIs are down.
### Command
You can use the ``/authback`` command on servers with the mod to manage your public keys or those of other players if you are an admin.
### Configuration
#### Client
You can configure the mod via ``Options > Online... > AuthBack...`` or if ModMenu is installed: ``Mods > AuthBack > Click Icon/Settings``
#### General
The configuration is dynamically loaded from (sorted by highest priority)
Environment variables
prefixed with ``AUTHBACK_
Full list of configuration options
_Please note that the preconfigured values usually work out of the box. _ _You should know exactly what you're doing when doing modifications._
##### Common (Client and Server)
| Property | Type | Default | Notes | | --- | --- | --- | --- | | `global-public-keys-cache.default-reuse-minutes` | `int` | `120` (2h) | The response for the global public keys of the Mojang's API barely ever changes. As of writing this documentation it has stayed the same the past 2+ years. This option instructs the mod to re-use the last saved response for the specified amount of minutes instead of contacting the API again. Using the cached response is a lot faster and saves network traffic during frequent game restarts. | | `game-profiles.delete-after-days` | `int` | `36` | 36 days was choosen as the default because when a player changes their username the name will be unavailable for 37 days | | `game-profiles.max-cache-size` | `int` | `250` | Maximum amount of game profiles to keep in the cache. If the size exceeds the maximum the oldest entries will be removed until the list is at 90% of the configured maximum. | | `username-to-id-resolver.use-vanilla` | `bool` | `false` | Use the original/"vanilla" username-to-id resolver | | `username-to-id-resolver.expire-after-days` | `int` | `36` | Days after which the cache entry will be deleted. 36 days was choosen as the default because when a player changes their username the name will be unavailable for 37 days. The vanilla implementation uses 1 month. | | `username-to-id-resolver.refresh-before-expire-days` | `int` | `14` | Days before the expiration when a cached entry will be refreshed when it's accessed. | | `username-to-id-resolver.max-cache-size` | `int` | `1000` | Maximum amount of usernames and ids to keep in the cache. If the size exceeds the maximum the oldest entries will be removed until the list is at 90% of the configured maximum. | | `username-to-id-resolver.resolve-offline-users-by-default` | `bool` | `true` | Should offline users (e.g. unvalidated accounts) be cached?. Please note
- the offline-user cache is completely separated from the online-user cache and will never be persisted.
- This is only the initial value
- Clients will always resolve offline users and server will only do so when `online-mode` was disabled
##### Server
| Property | Type | D
📊 Mod Details
- Game
- Minecraft Mods
- Author
- litetex
- Version
- 1.9.0-SNAPSHOT
- Downloads
- 3,260
- Endorsements
- 24
- Category
- fabric
- Created
- 11/28/2025
- Updated
- 8/21/2026
- Game Versions
- 26.3-snapshot-9
- Tags
- management, technology, utility
🔧 How to Install Minecraft Mods Mods
Download from Modrinth. Use Prism Launcher or drop into your mods folder.
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Visit the official mod page for specific installation instructions for this mod.
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❓ Frequently Asked Questions
Which Minecraft Mods versions does AuthBack support?
The author lists 26.3-snapshot-9. Other versions may work but are untested by the author.
What is the latest version of AuthBack?
Version 1.9.0-SNAPSHOT, published 2026-08-21 with 3,260 downloads recorded at the source.
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