ImplicitSave — Zero-Config Save System

ImplicitSave is a save system for Unity where declaring a class is the entire setup.

[SaveId("items")]
public class ItemsSaveData : SaveData
{
public int Coins;
public SerializableDictionary Bag;
}

var items = SaveManager.Get();
items.Coins += 10;

That is the whole integration. No central ScriptableObject to maintain, no manual registration, no references to drag into a field, and no save manager prefab to keep in every scene. Changes are written on their own: on the autosave tick, when the app is paused or loses focus, and on quit.

WHAT YOU GET
• Zero-config discovery — a class deriving from SaveData is found, given a file, and kept as one live instance per profile. Discovery uses TypeCache in the editor and a generated registry in builds, so it survives IL2CPP with managed stripping set to High. There is a window listing every type found and what each one is called on disk, because a system you cannot inspect is a system you cannot trust.

• A Save Editor window — open, read and edit any save file from inside Unity, including while the game is running, against the live instance. It draws your own custom property drawers.

• Dictionaries that survive on every version you support — SerializableDictionary ships with a drawer and works from 2021.3 on, and the file stays readable: {"potion": 3}. Unity 6.6 added native Dictionary serialization, and those fields are saved too when you run on 6.6 or newer: the package follows the editor's rules rather than a hard-coded list.

• Save slots (profiles) — create, switch, copy, rename and delete. The same save class is stored once per slot, so a "load game" screen needs no second class.

• Schema migration — versioned files and migration steps applied in order, found on their own. A file written by a NEWER build of your game is never overwritten, so a player who downgrades does not lose progress.

• Polymorphic fields — a List holding swords, potions and bows keeps every subtype through a save, persisted by a stable id instead of a .NET type name. Renaming a class does not break saves.

• Unity's built-in structs — Vector2/3/4, Quaternion, Color, Rect, Bounds, LayerMask, Hash128 and the rest, saved with the names their C# API uses.

• Atomic writes with a backup — a crash mid-write cannot leave a corrupt file, and a file that cannot be read is recovered from its .bak.

• Validation on compile — fields that would silently never reach the file (a Dictionary, a property, a class without [Serializable], nesting deeper than Unity serializes) are reported with the fix, in the console, before a player ever hits it.

• Plain JSON on disk — open it in any text editor. Nothing is hidden in a binary blob.

SAMPLES
Four of them, each a scene to press Play on: Basic Usage (the demo scene), Multi Profile, Polymorphism and Migration.

REQUIREMENTS
• Unity 2021.3 or newer.
• Json.NET ("com.unity.nuget.newtonsoft-json") is installed for you on import - it is declared as a package dependency. ImplicitSave never ships its own copy of Json.NET, which is what keeps it from clashing with other assets that use it. If your project already has Json.NET as a loose DLL, keep a single copy.

TESTED
The full test suite runs on Unity 2021.3 LTS, 2022.3 LTS, Unity 6.0 and Unity 6.6, on every change, in continuous integration. The IL2CPP path is verified on a real Android device with managed stripping on High, because that is where a save system usually breaks.

SUPPORT AND SOURCE
Support happens through GitHub Issues: https://github.com/bionics07/Implicit-Save
The source is there too, MIT licensed. Copies obtained through the Asset Store are governed by the Asset Store EULA instead - same code, same features, either way.
ImplicitSave is free.

Donations accepted at https://ko-fi.com/bionics07