Save/Load Systems -- Decision Patterns

Prerequisite skills: unity-lifecycle (OnApplicationPause, OnApplicationQuit, quit sequence), unity-data-driven (JSON serialization, versioning), unity-packages-services (Cloud Save API), unity-async-patterns (BackgroundThreadAsync)

These patterns address the most common save system failure: Claude uses PlayerPrefs for everything, produces brittle serialization with no versioning, and ignores mobile-specific persistence requirements.

PATTERN: Serialization Format Selection

WHEN: Choosing how to serialize save data to disk

DECISION:

• JSON (JsonUtility) -- Human-readable, debuggable, small save files. No dictionary/polymorphism. Best default for most games.
• JSON (Newtonsoft) -- Full JSON features (dictionaries, polymorphism, LINQ). Slightly larger dependency. Best when save data is complex.
• Binary (custom or MessagePack) -- Performance-critical, large saves, anti-cheat (harder to edit). Not human-readable. Best for competitive games or very large worlds.
• BinaryFormatter -- NEVER USE. Security vulnerability (arbitrary code execution on deserialization). Deprecated by Unity and Microsoft.