Unity Nearby Connections Transport — Documentation

This folder contains the official documentation for Unity Nearby Connections Transport, a custom transport for Netcode for GameObjects (NGO) built on top of Google Nearby Connections.

These documents describe installation, usage, design intent, platform notes, and known limitations.

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Installation

OpenUPM (recommended)

openupm add com.bernatrosello.nearby-connections-transport

When installed through OpenUPM, all required dependencies are resolved automatically.

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Manual / Git installation

If you clone or embed this repository manually, you must also install EDM4U.

Required dependency: EDM4U

External Dependency Manager for Unity (EDM4U) is required to resolve and fetch:

• Google Play Services
• The Nearby Connections API used internally by this transport on Android

EDM4U is responsible for generating the correct Gradle dependencies so the Nearby Connections API is included at build time.

Install EDM4U via OpenUPM:

openupm add com.google.external-dependency-manager

Or from GitHub: https://github.com/googlesamples/unity-jar-resolver

Without EDM4U, Android builds will fail or the Nearby API will be missing at runtime.

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Quick Start

1. Install Netcode for GameObjects
2. Install Unity Nearby Connections Transport
3. Add NBCTransport to your scene
4. Assign it as the Transport in NetworkManager
5. Configure Host / Client options

using Netcode.Transports.NearbyConnections;

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Connection Model

This transport uses Google Nearby Connections to establish peer-to-peer links over:

• Bluetooth
• Wi‑Fi Direct
• Nearby Wi‑Fi

It is designed for local / offline networking scenarios.

Strategies

• P2P Star — One host, many clients (recommended for NGO)
• P2P Cluster — Mesh-like topology
• P2P Point-to-Point — Single high-bandwidth link

Event-driven design

This transport is purely event-driven:

• No socket polling loop
• PollEvent() always returns Nothing
• Native callbacks are marshalled onto Unity’s main thread

NGO still receives standard Connect, Disconnect, and Data events.

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Android Notes

Permissions

The following permissions are required and requested at runtime:

• Bluetooth Scan / Connect / Advertise
• Nearby Wi‑Fi Devices
• Location (required by Nearby Connections)

Permission handling is automatic on Android builds.

Build system

• Java bridge compiled as an Android library
• Native C++ plugin accessed via P/Invoke
• Google Play Services resolved through EDM4U

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Performance Notes (Initial Release)

This is the first public release of the transport.

Observed performance

Initial testing shows:

• ~160 ms mean ping in typical local scenarios
• Performance varies based on:
  • Connection strategy
  • Radio technology selected by Nearby
  • Device hardware

These values are expected for Nearby Connections, which prioritizes reliability and discovery over raw latency.

Profiling tools

You can profile runtime behaviour using:

• Unity's Multiplayer Tools - Runtime Network Stats Monitor

For deeper analysis of the underlying Nearby Connections API, a dedicated performance report was conducted using a custom release of:

https://github.com/BernatRosello/AtomD/

This external tool focuses on evaluating Nearby Connections behaviour independent of NGO.

More performance tuning and benchmarks are planned for future releases.

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Limitations

• Android is the primary supported platform

• iOS / visionOS bindings are stubs, which contributors might want to submit PRs for, a good starting point might be found in the work being done over at the google/nearby/connections repo. Though this isn't the actual implementation of Nearby Connections that runs natively on Android (closed source), it does presumptuously share interfaces with it. In fact a fork of this repo was used to develop the C++ JNI bindings that call into the underlying java code used on this package, those might be of help too.

• Throughput and latency are constrained by Nearby Connections

• Not intended for large-scale or internet-based multiplayer

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Intended Use Cases

• Local multiplayer games
• Party / couch co‑op
• Device‑to‑device discovery
• Offline networking scenarios

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License

MIT License

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Status

This transport is under active development.

Feedback, issues, and contributions are welcome.