StreamBridge (Valheim)

A lightweight host-only bridge for Valheim that listens on localhost and executes gameplay actions sent as JSON over HTTP. It is designed to be used by companion apps/bots during streams (e.g., chat-triggered spawns, item rewards, or temporary effects).

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📥 Download & Installation

⚠️ Requires BepInEx 5.
BepInEx 5 must be installed into your Valheim folder and the game launched once so that it creates required folders (BepInEx\plugins, BepInEx\config, BepInEx\core).
This is a one-time setup step — both release users and developers must do this before StreamBridge will work.

➡️ Releases Page

1. Download the zip file ValheimBridgeMod.zip from the release assets.
   This archive contains the StreamBridge plugin folder with the DLL already built.
2. Extract the contents directly into your Valheim plugins directory:

   Valheim\BepInEx\plugins\
   

   After extraction, you should have:

   Valheim\BepInEx\plugins\StreamBridge\StreamBridge.dll
   Valheim\BepInEx\plugins\StreamBridge\Newtonsoft.Json.dll
   Valheim\BepInEx\plugins\StreamBridge\Newtonsoft.Json.xml
   

3. Launch Valheim once to auto-generate:

   Valheim\BepInEx\StreamBridge\StreamBridge.cfg
   

4. (Recommended) Download CommandsTester.html from the release assets to quickly generate and test commands from your browser.

That’s it — you’re ready to connect local apps and/or use the included tester page.

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🛠️ Development Setup

Whether you want to build from the included codebase or start your own project, you must first complete the one-time prerequisite:

• Install BepInEx 5 (x64) into your Valheim folder:

  C:\Program Files (x86)\Steam\steamapps\common\Valheim\
  

• Launch Valheim once to generate required folders:

  BepInEx\plugins\
  BepInEx\config\
  BepInEx\core\
  

• Install Visual Studio 2022 with the .NET desktop development workload.
• (Optional but useful) Install dnSpy/ILSpy to explore Valheim APIs.

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Option A: Build from this codebase

1. Clone the repository:

   git clone https://https://github.com/DakotaCondos/ValheimBridgeMod.git

2. Open the solution in Visual Studio 2022.

3. Ensure target framework is .NET Framework 4.7.2 (compatible with Valheim + BepInEx 5).

4. References should already be set up in the project:

   • 0HarmonyLib.dll
   • BepInEx.dll
   • assembly_valheim.dll
   • assembly_utils.dll
   • UnityEngine.CoreModule.dll
   • UnityEngine.PhysicsModule.dll
   • UnityEngine.dll
   • Newtonsoft.Json.dll

5. Set build output path so the DLL lands directly in your Valheim plugins folder:

   Valheim\BepInEx\plugins\StreamBridgeMod\
   

6. For packaging, create a folder called StreamBridge with the DLL inside, zip it, and attach to a GitHub release.
   For local testing, place the DLL under:

   Valheim\BepInEx\plugins\StreamBridge\
   

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Option B: Create a project yourself (manual setup)

0. Prerequisites: BepInEx installed + run once (as described above).

1. In Visual Studio:

   • File → New → Project…
   • Template: Class Library (.NET Framework)
   • Project name: StreamBridgeMod (or your choice)
   • Target framework: .NET Framework 4.7.2

2. Add required references manually:

   • From <Valheim>\valheim_Data\Managed\:
     assembly_valheim.dll, assembly_utils.dll, UnityEngine.dll, UnityEngine.CoreModule.dll
     (Optionally add more UnityEngine.* modules if you need them.)
   • From <Valheim>\BepInEx\core\:
     BepInEx.dll, 0Harmony.dll
   • Via NuGet: add Newtonsoft.Json (Copy Local = True so it ships with your DLL).
   • For all Unity/BepInEx references: set Copy Local = False to avoid copying them into your build output.

3. Set build output path so the DLL lands directly in your Valheim plugins folder:

   Valheim\BepInEx\plugins\StreamBridgeMod\  
   

4. Build → Build Solution (Ctrl+Shift+B).
   Ensure the DLL appears under BepInEx\plugins\StreamBridgeMod\.
   Also ensure Newtonsoft.Json.dll sits next to it if not already provided.

5. Launch Valheim and check BepInEx\LogOutput.log — you should see:

   Stream Bridge listening on http://127.0.0.1:28575/command
   

6. The rest of development is up to you!

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Configuration

(File: BepInEx/StreamBridge/StreamBridge.cfg, created automatically on first run)

Section	Key	Default	Purpose
Network	Port	28575	Local HTTP port (127.0.0.1 only)
Limits	MaxSpawned	50	Max spawn count per command
Limits	MaxDelay	30	Max stagger delay (seconds)
Limits	MaxTTL	600	Max time-to-live (seconds)
Limits	MaxStars	2	Max mob star level (0..2)
UI	Notify	true	Show HUD toasts

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API

Endpoint:
POST http://127.0.0.1:<Port>/command
OPTIONS preflight is supported (CORS).

The body must be JSON with a commands array. Each command has an id, type, and payload.
See the included User Guide for detailed examples of item.give, effect.apply, and spawn.* commands.

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Contributing

• Issues and PRs welcome.
• Please document any new payload fields in the User Guide.
• For testing during development, use CommandsTester.html.

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License

MIT © 2025 StreamBridge contributors — see LICENSE-MIT.txt for full text.
This license applies only to code in this repository. Valheim assets, names, and trademarks are property of their respective owners.

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