Modding:Content Patcher
Creating Content Patcher packs 
Do you want to create Content Patcher packs for Stardew Valley? This guide is for you! For using mods, see Modding:Player Guide.
Intro
What is Content Patcher?
Content Patcher is a SMAPI mod which lets you change the game assets (images, dialogue, data, and maps) without replacing game files or writing code. You use it by creating a content pack (basically a folder with certain files) with a couple of JSON files. Just by editing a JSON file, you can...
- replace one image file;
- make seasonal changes;
- make dialogue that changes based on the weather, date, your relationships with other NPCs, etc;
- make very specific changes (like coffee is more expensive on winter weekends when it's snowing after you've completed the JojaMart);
- and much more.
Content Patcher vs other mods
Content Patcher supports all game assets with some very powerful features, but it's a general framework. More specialised frameworks might be better for specific things. You should consider whether one of these would work for you:
- Advanced Location Loader for complex changes to maps. (For simple changes, see edit maps.)
- Custom Farming Redux to add machines.
- Custom Furniture to add furniture.
- Custom Shirts to add shirts.
- Json Assets to add items, crafting recipes, crops, fruit trees, hats, and weapons.
(For a comparison with legacy XNB mods, see using XNB mods.)
Content Patcher vs SMAPI
SMAPI is the modding API used to add mods to the game (Content Patcher itself is a SMAPI mod). If the mod you want to create is possible with Content Patcher, that's recommended since it's easier to maintain and update. However, you can also program a mod using SMAPI directly if you want; see creating SMAPI mods for more info.