save-systems

1# Save systems
2 
3A save file is a **serialized snapshot of game state** that survives restarts.
4The hard parts aren't writing bytes — they're choosing *what* to save, writing it
5so a crash mid-save can't corrupt it, and reading *old* saves after you ship a
6patch. Get those three right and the rest is plumbing.
7 
8## When to use
9 
10- Use to persist progress: player stats, inventory, world flags, settings,
11  positions — across sessions and game updates.
12- Use to design save slots, quicksave/autosave, and crash-safe writes.
13- Use when old save files break after a content/code change (versioning &
14  migration).
15 
16**When *not* to use:** for Roblox cloud persistence specifics, use
17`roblox-datastores`. For the data model the save serializes (resources/SOs), use
18`godot-resources` / `unity-scriptableobjects`. For Godot's `FileAccess`/
19`ResourceSaver` and `user://` paths, defer to the Godot engine skill while
20applying the patterns here.
21 
22## Core workflow
23 
241. **Decide what state is authoritative.** Save the *data* (hp, position, seed,
25   unlocked flags), not engine objects or scene nodes. You will reconstruct
26   objects from data on load — never serialize live node references.
272. **Define a versioned schema.** Every save embeds a `version` integer. This is
28   the single most important field for a game you intend to patch.
293. **Pick a format.** JSON/text for readability and debuggability; a binary
30   format for size/speed or mild tamper-resistance. Start with JSON.
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