S1API

S1API is a modular, developer-friendly API for building mods for Schedule One. It provides a stable abstraction layer over the game's internals with a focus on:

• Cross-compatibility between Mono and IL2CPP
• A first-class Phone App framework
• A lightweight UI factory for fast, consistent UI creation
• An ergonomic save system for mod data
• High-level wrappers for common systems (Phone Calls, Quests, NPCs, Items, etc.)
• Clean logging utilities

The goals are predictable behavior, safe integration with the base game, and a smooth developer experience.

Highlights

• Cross-runtime configurations: MonoMelon, Il2CppMelon
• Phone App lifecycle: registration, icon spawning, open/close handling, input integration
• UI primitives: panels, lists, buttons, layouts, and helpers via UIFactory
• Saveables: annotate fields and get robust JSON persistence per-save-slot
• Phone Calls: define callers, build multi-stage calls, and queue safely into the game's system

Quick Links

• Getting started: getting-started.md
• Phone Apps: phone-app.md
• UI Factory: ui.md
• Save System: save-system.md
• Phone Calls: phone-calls.md
• Logging: logging.md

If you're looking for a practical example, see the S1NotesApp mod which implements a full in-game Notes application using S1API's PhoneApp and Saveables systems.