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Seamless - Serverless Multiplayer project artwork

Modrinth · Minecraft mod

Seamless - Serverless Multiplayer

Play together instantly. No server needed. Host your singleplayer world and invite friends in seconds.

Choose a version Pick your version below, then grab the matching file.

Quick answer

Which Seamless - Serverless Multiplayer release should I use?

Updated 6 months ago
beta file 1.1.8
Game version 1.21.11
Loader NeoForge

Seamless - Serverless Multiplayer 1.1.8 targets 1.21.11 with NeoForge. Installation on the client is optional. Installation on the dedicated server is optional. No extra mods listed for this file.

Where it goes

Is Seamless - Serverless Multiplayer required on the client, server, or both?

Installation on the client is optional. Installation on the dedicated server is optional.

Client Optional
Dedicated server Optional
Loader for this release NeoForge
Required install it here Optional supported, not mandatory Not supported do not install here Source doesn’t say do not assume

The source marks this as usable on both the client and server.

What else does Seamless - Serverless Multiplayer 1.1.8 need?

1.1.8. Change the file and its required mods may change too.

No extra mods listed for this file

This file does not list any required mods. Do not add a library just because a different file uses it.

This file does not list any required or optional mods.

Before you install it

Add Seamless - Serverless Multiplayer without breaking your instance.

Built for Seamless - Serverless Multiplayer 1.1.8. Pick another file and the loader, install side or required mods may change.

  1. 01

    Stick to this file

    Use 1.1.8. It targets 1.21.11 with NeoForge; another release may have different loader, side or dependency requirements.

  2. 02

    Bring the mods it needs

    This file does not list any required mods. Do not add a library just because a different file uses it.

  3. 03

    Put it on the correct side

    Installation on the client is optional. Installation on the dedicated server is optional.

  4. 04

    Pick the file you checked

    Use the “Get this file” button beside 1.1.8. It opens that exact file at the source.

About this project

What does Seamless - Serverless Multiplayer add?

Banner

CurseForge Modrinth Fabric NeoForge

Seamless - Play Together, Effortlessly

Tired of complicated server setups? Seamless transforms multiplayer gaming by eliminating the technical headaches. No port forwarding nightmares, no router configuration struggles – just pure gaming fun with your friends!

What Makes Seamless Special?

Seamless revolutionizes how you play Minecraft with friends by bringing server hosting directly into your game. Using cutting-edge P2P technology, it automatically establishes connections between players, even when both are behind NAT or firewalls. Say goodbye to technical barriers and hello to instant multiplayer!

Key Features

One-Click Server Hosting

Launch a multiplayer server directly from Minecraft – no separate server software, no console commands, no complexity. Just click "Host Server" and you're ready to play!

Automatic Port Forwarding

Forget about router configuration! Seamless automatically handles port forwarding using UPnP technology. If automatic setup isn't possible, you'll get clear, easy-to-follow instructions.

Smart Invite System

Share a simple 6-digit code instead of complicated IP addresses. Your friends can join in seconds by entering the code – it's that simple!

Integrated Friend Management (Coming Soon)

Manage your friends directly in-game with real-time status updates and persistent friend lists.

Advanced P2P Connections

Modern networking technology that works even behind NAT and firewalls. Direct peer-to-peer connections with automatic fallback to relay servers if needed.

Mod Compatibility Checker

Never join an incompatible server again!

  • Automatic mod detection on host and client
  • Pre-join compatibility checks – see warnings before connecting
  • Prevent crashes caused by mod mismatches
  • Clear mod requirement lists for easy troubleshooting

Real-Time Session Management

  • Live player counts and session status
  • Automatic session cleanup after 1 hour of inactivity
  • Session restoration – rejoin seamlessly after disconnects

Cross-Platform Support

Works with both Fabric AND NeoForge – same great features, same smooth experience, your choice of mod loader!

Quick Start Guide

Hosting Your First Server

  1. Open the game menu
  2. Click "Server"
  3. Hit "Start Server"
  4. Share your invite code or server address with friends
  5. Start playing together! 🎉

Joining a Friend's Server

Currently, joining works via 6-digit invite codes:

  1. Get the code from your friend hosting the server
  2. Open the join menu in Seamless
  3. Enter the 6-digit code
  4. Connect instantly!

Note: The friend list feature is currently in development. For now, use invite codes to join servers.

🔧 Technical Details

Network Architecture
  • Standard Minecraft protocols with automatic port detection
  • Multi-tier connection strategy (direct → hole-punch → relay)
  • RFC 5389-compliant STUN client implementation
P2P Technology
  • STUN servers for NAT traversal
  • UDP hole punching for firewall bypass
  • TCP-over-UDP tunneling with automatic fallback
Data Storage
  • Friend lists: config/seamless/friends.json
  • Server settings: Local configuration files

Community & Support

Need help? Have suggestions? Found a bug?

  • Report issues on CurseForge
  • Leave comments on CurseForge – i read every message!
  • Share your experience – help me improve Seamless

Currently in Development

The following items reflect the current direction of development.
These are planned features, not guarantees. Stability comes first.

Core improvements
  • In-game friends menu
  • Inviting friends directly without links
  • Minimal UI with no social features
  • No accounts, cosmetics, shops, or external services
  • Calm behavior without spam notifications
  • Focus on hosting and joining only
Multiplayer and co-op features
  • Basic multiplayer commands
  • Host-only permissions
  • Session-based commands like kick, invite, and lock session
  • Clear host indication
  • Better session lifecycle handling
  • Optimized for small groups
  • Target: stable sessions with up to 8 players
Mod and Voice support
  • Improved modpack compatibility
  • Support for common mod setups
  • Simple Voice Chat compatibility
Versions

Planned support for additional versions:

  • 1.21.4
  • 1.21
  • 1.20.4
  • 1.20.1
  • 1.19.2
  • 1.12.2
  • 1.7.10

The focus is on supporting the most important versions first, with others coming later.

Modpacks

Seamless is explicitly allowed to be used in modpacks.

If you want to include Seamless in a public or private modpack, feel free to do so.
The only requirement is that all players in a session use the same mod setup.

If you run into issues, incompatibilities, or edge cases while integrating Seamless into a modpack, modpack creators are very welcome to reach out.
Feedback from modpack authors is appreciated and helps improve compatibility.

License

All rights reserved.

Credits

Developed with ❤️ by Ecentrix

Special thanks to the Minecraft modding community and everyone who contributes to making multiplayer gaming more accessible!

Ready to play without limits?

Download Seamless today and experience multiplayer the way it should be!

No technical knowledge required – just install and play.

Project description from Modrinth.

Pick your setup

Seamless - Serverless Multiplayer by Minecraft version and loader

Choose the version and loader you play, then open the matching release.

9 available setups

Check the dependencies, then try the file in a copied instance before changing a world you care about.

Recent files

Seamless - Serverless Multiplayer versions and loaders

21 of 21 releases match

Looking for an older file? The official Modrinth project page is in Resources.