Modding:Modder Guide/Get Started

Do you want to create SMAPI mods for Stardew Valley? This guide is for you! For using mods, see Modding:Player Guide.

Intro

What is a SMAPI mod?

A SMAPI mod uses the SMAPI modding API to extend the game logic. The mod can respond when something happens in the game (like when an object is placed in the world), run code periodically (like once per update tick), change the game's assets and data, etc. SMAPI mods are written in C# using the .NET Framework, and Stardew Valley uses XNA/MonoGame for the game logic (drawing to the screen, user input, etc).

Why do mods use SMAPI?

SMAPI does a lot for you! For example, SMAPI will...

1. Load your mod into the game. Code mods aren't possible without SMAPI to load them.
2. Provide APIs and events which let you interact with the game in ways you otherwise couldn't. There are simplified APIs for game asset/data changes, player configuration, translation, reflection, etc. These are covered later in the guide.
3. Rewrite your mod for crossplatform compatibility when it's loaded. That lets you write mod code without worrying about the differences between the Linux/Mac/Windows versions of the game.
4. Rewrite your mod to update it. SMAPI detects and fixes mod code broken by a game update in common cases.
5. Intercept errors. If your mod crashes or causes an error, SMAPI will intercept the error, show the error details in the console window, and in most cases automatically recovers the game. This means your mod won't accidentally crash the game, and makes it much easier to troubleshoot errors.
6. Provide update checks. SMAPI automatically alerts players when a new version of your mod is available.
7. Provide compatibility checks. SMAPI automatically detects when your mod is incompatible and disables it before it causes problems, so players aren't left with broken games.

Can I make a mod?

Yes! This guide will help you create a simple mod step-by-step. If you follow along, you'll have created a mod! Then you'll just need to make it do what you want.

If you're new to programming: many mod developers start with little or no programming experience. You can certainly learn along the way if you're determined, but you should be prepared for a steep learning curve. Don't be too ambitious at first; it's better to start with a small mod when you're figuring it out. It's easy to become overwhelmed at first and give up. The modding community is very welcoming, so don't be afraid to ask questions!

If you already have programming experience, you should be fine. Programming experience in C# or Java will make things easier, but it isn't critical. If you're unfamiliar with C#, you can skim through the Learning C# references below to fill in any gaps.

Can I make a mod without SMAPI?

Yep. Many SMAPI mods support 'content packs', which let you provide JSON text files, images, etc which they use. For example, you can use Content Patcher to edit the game's images and data with zero programming needed. The rest of this guide is about creating a new SMAPI mod; for content packs, see the documentation for the mod that'll read it.

Where can I get help?

The Stardew Valley modding community is very welcoming. Feel free to ask for help in #modding on the Stardew Valley Discord.

Getting started

Learning C#

Since mods are written in C#, it's a good idea to get acquainted with it first. You don't need to memorise everything, but a grasp of the basics (like fields, methods, variables, and classes) will make everything else much easier.

Some useful resources:

• C# Quickstarts teaches the basics of C# with interactive examples.
• C# Fundamentals for Absolute Beginners is a video guide which will walk you through C#, from the basic concepts to event-driven programming (which is what SMAPI mods mostly use).

Requirements

Before you start:

1. Read the Player Guide. The rest of this guide assumes you're already familiar with using mods.
2. Install Stardew Valley.
3. Install SMAPI.
4. Install the IDE (integrated development environment).
   • On Linux: install MonoDevelop.
   • On Mac: install Visual Studio 2017 for Mac. (This is a rebranded MonoDevelop.)
   • On Windows: install Visual Studio 2017 Community. When the installer asks about workloads, enable .NET Desktop Development.

If you're not familiar with Visual Studio 2017 (on Windows/Mac) or MonoDevelop (on Linux), Modding:IDE reference explains how to do the important stuff you need for this guide.

Creating a Basic Mod →