About Sideload
From ThunderstoreWrite a mod interface as HTML, CSS and JavaScript. Sideload renders the web bundle into real Unity UI and puts it on the in game phone, so an app is three files instead of a thousand lines of panel code.
Sideload - Web UIs for Schedule I Mods
> 🛟 Need help or found a bug? Get support at support.doodesch.de/sideload.
> A framework, not a feature. Sideload renders mod interfaces written as index.html + app.css + > app.js into real Unity UI and TextMeshPro. No browser, no native code, no subprocess. Install it because > a mod you want depends on it.
Source + docs · Reference app (WhatsDab) · Support
Players
Sideload adds no gameplay, no menu and no phone app of its own. Mods that build their interface with it list it as a dependency and your mod manager installs it for you. It sits idle until one of those mods registers an app, and every developer tool inside it is off until you switch it on.
Installed by hand? Sideload.dll goes in Mods/. That is all of it - AngleSharp, Jint and Esprima are inside that one file.
Mod authors
- HTML instead of nested panels, CSS instead of
sizeDeltaarithmetic. Real flexbox, a real cascade,
real selectors, TextMeshPro text.
- One call for a phone app.
Apps.Register(id, bundlePrefix, title)and your bundle renders behind an
icon on the in game phone. Registering before Sideload loads is fine; the call replays.
- A two way bridge.
s1.call('name', arg)reaches a C# handler in the same frame and returns its string;
app.Emit('name', payload) pushes back into s1.on(...).
- Chrome DevTools. One preference and the real inspector attaches to a page running inside the game:
console, evaluate, Elements tree, reload from disk.
- No hard dependency. The
Sideload.Apishim is one file with zero references. It is a no op when
Sideload is absent and lights up when it is there, so your mod ships one DLL either way.
fetchis default deny. A page reaches no host until your mod names it withAllowHost.
Start here: WhatsDab is a complete chat app for the in game phone, written as three web files, that you can install, read and copy. The step by step guide, the exact CSS subset and the layout rules that differ from a browser are in the wiki.
Requirements
Schedule I (IL2CPP) with MelonLoader 0.7.3+. S1API is optional: with it installed, pages can read the game by name (s1api).
Settings
Under Sideload_01_Main in UserData/MelonPreferences.cfg. All of it is developer tooling and all of it is off by default.
DevTools (false) turns on the Chrome DevTools Protocol server on 127.0.0.1; anything that can reach that port can run code in your pages, so leave it off unless you are building an app. DevToolsPort (9333) is the loopback port. DevToolsAutoOpen (true) opens the browser at the landing page once the first page mounts. DevToolsFetchFrontend (true) lets Sideload download the DevTools interface once into UserData/, so the inspector works offline afterwards. DevToolsFrontend (empty) overrides that with a folder holding your own copy.
License
DooDesch API License - build on the API, do not copy the code. See LICENSE.md. Bundles AngleSharp (MIT) and Jint with Esprima (BSD-2).
Highlights
From source dataLoaders
Runs on BepInEx.
Footprint
Rated a light load on a server.
Last update
Its author last shipped an update today.
Sideload on Nxeon
From our catalogue- One-click install
- Not available. One-click install isn't available for this game's mods yet. Download it and upload it to your server in Files.
- Server type needed
- BepInEx
- Server load
- light
- Latest build
- 1.36.3, released 2026-11-03
Game versions by loader
| Loader | Game versions | Newest |
|---|---|---|
| BepInEx |
From 29 recorded builds of Sideload.
Recent builds
| Build | Released | Game versions | Loaders |
|---|---|---|---|
| 1.36.3 | 2026-11-03 | n/a | BepInEx |
| 1.36.2 | 2026-11-02 | n/a | BepInEx |
| 1.36.1 | 2026-10-31 | n/a | BepInEx |
| 1.36.0 | 2026-10-29 | n/a | BepInEx |
| 1.35.0 | 2026-10-24 | n/a | BepInEx |
| 1.34.0 | 2026-10-23 | n/a | BepInEx |
Dependencies
- Required: MelonLoader
Declared by the newest build that lists any. Required ones are installed with it on one-click installs.
What kind of mod it is
From the catalogQuality of life & UI
Small conveniences, tweaks and interface improvements players notice straight away.
Compatibility
- Game
- Schedule I
- Loaders
- BepInEx
- Requires
- One-click install needs a BepInEx server.
Verified at the source
- ✓ThunderstoreOfficial listing, checked 2026-11-03Open ↗
- ✓AuthorDooDesch, as published on Thunderstore
- ✓LicenseNot published by the sourceFree



