Sideload

v1.33.0·Updated 2026-09-01

Write 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 co

About this mod Author’s original text

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 sizeDelta arithmetic. 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.Api shim 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.

  • fetch is default deny. A page reaches no host until your mod names it with AllowHost.

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+. No 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

MIT. See the included LICENSE.md. Bundles AngleSharp (MIT) and Jint with Esprima (BSD-2).

Install & use Install: follow the bundled instructions

  1. Unzip the archive from playbuff and read the bundled readme / instructions first.
  2. Most mods rely on the game's mod loader — the usual route is a community mod manager (such as r2modman): pick this game, install, and it handles the loader and dependencies.
  3. For a manual install, put the mod files into the matching Mod / plugins folder inside the game directory.
  4. Launch the game to confirm it loaded; mods with listed dependencies need those installed as well.

Install locations vary a lot between mods — the bundled readme is the most reliable guide.

Dependencies

Install these first, or the mod will not work:

LavaGang-MelonLoader

File & checksum

Filename
Sideload-1.33.0.zip
File size
1.2 MiB