Registry Snapshots

📸 Registry Snapshots

Registry Snapshots is a lightweight developer tool for NeoForge 26.2 that makes it easy to see exactly what changed in Minecraft’s registries between builds.

Save a registry state, make changes to your mod, then compare it against the current game state to instantly find added or removed entries.

✨ Features

• 📦 Save deterministic registry snapshots as JSON
• 🔍 Compare saved snapshots against each other or the current runtime state
• ➕ Clearly display added registry entries
• ➖ Clearly display removed registry entries
• 🧠 Automatic in-memory startup baseline for the current session
• 🧩 Support for NeoForge custom registries
• ⚙️ Include or exclude custom registries through configuration
• 📄 Export and inspect saved snapshot information
• 🗑️ Safely delete snapshots, including corrupted files
• 🛡️ Corrupted or unsupported snapshots are handled without crashing the game
• 📊 Built-in benchmark command for testing capture, serialization, parsing, and diff performance
• 💾 No automatic snapshot spam — persistent snapshots are only created when you ask for them
• 🔒 Read-only by design — Registry Snapshots never modifies your registries

🧪 Perfect for Mod Development

Registry Snapshots is useful when you:

• Add or remove blocks, items, fluids, entities, menus, or other registered content
• Rename registry IDs between builds
• Debug missing or unexpected registrations
• Compare two versions of a mod
• Verify that a registration change actually reached the runtime registry
• Check large modpacks without manually searching through thousands of registry entries

⌨️ Commands

/regsnap
Shows the current registry overview.

/regsnap save <name>
Saves the current registry state as a deterministic JSON snapshot.

/regsnap list
Lists all saved snapshots.

/regsnap list open
Opens the snapshot folder on supported local systems.

/regsnap diff <old> <new|current>
Compares two snapshots or compares a saved snapshot against the current registry state.

/regsnap diff startup current
Compares the current registry state against the in-memory startup baseline.

/regsnap export <name>
Validates a snapshot and displays its JSON location and summary.

/regsnap delete <name>
Deletes a saved snapshot.

/regsnap benchmark
Runs an in-memory performance and determinism benchmark without writing files.

📁 Snapshot Format

Snapshots use a versioned, deterministic JSON format. Registry IDs and their entries are stored in a stable order, making snapshots suitable for reliable comparisons between builds.

Example diff:

Registry Diff • before_update → current

minecraft:item
+ examplemod:new_machine
+ examplemod:new_component
– examplemod:old_machine

minecraft:fluid
+ examplemod:coolant

Summary: +3  -1

⚡ Lightweight by Design

Registry Snapshots does not continuously scan registries, modify game data, or write files in the background.

Persistent snapshots are only created through explicit commands, while the session startup baseline stays in memory.

🔧 Platform

• Minecraft 26.2
• NeoForge
• Java 25
• Client + Server

Registry Snapshots is completely standalone and does not require the other Kiyoshibara developer tools.

💡 Save it. Change it. Diff it.