PacketInspector
by QURATOR
PacketInspector is a developer-focused Fabric tool that shows the Minecraft network packets a client sends and receives, in the game itself.
What it does
The mod watches the client-side packet stream in real time and lists each packet as it arrives. Entries can be filtered, and a history of recent packets is kept so a session can be looked over after the fact. Each packet is opened into its fields, so the structure of a protocol message can be read without decoding raw bytes by hand.
Beyond field inspection, the tool includes a built-in NBT viewer for ItemStack components and offers raw Java and JSON representations of the data. A packet replay mode is available for development and testing workflows, and the tool is intended for debugging and protocol research. It runs on the client alone, so servers do not need it and players join without installing anything.
The mod requires Fabric API. It is published for Fabric only, across 13 release versions 1.20.1 – 1.21.11, with 1.1.0 for 1.21.11 as the latest file. The code is released under the MIT License, and the mod is not open source.
Key features
Live packet stream
Client-side packets appear in an in-game list as they are sent or received, with filters applied to the stream.
Structured field inspection
Selecting a packet shows its fields in a record view, so each value in a classic packet can be read directly.
NBT viewer
A built-in viewer opens the NBT data of ItemStack components for inspection.
Raw Java and JSON modes
Packet data can be shown as raw Java or as JSON, and a replay mode resends captured packets for testing.
Gallery
Compatibility
Latest build for each game version and loader.
1.21.x12 of 12 versions with builds
1.20.x1 of 1 version with builds
Only full game releases are shown. This mod publishes no snapshot builds.
Requirements
Dependencies declared by the latest file for each loader.
Required 1
Use cases
Who it’s for: Mod developers, protocol researchers and players who want to see the packet traffic behind what they do in game. Because the tool exposes raw data, it is aimed at readers who already know the basics of the protocol.
How it compares
Instant Replay Mod is client-side only, licensed under the GNU General Public License v3.0 only, open source, and published for 1.20 – 1.21.11, so it records gameplay rather than packets. Packet Ninja is also client-side only and open source under the GNU Lesser General Public License v3.0 only, with files for 1.21.8 – 1.21.11, a shorter range than PacketInspector's. Format is open source under the MIT License, targets 1.20 – 1.21.3 and requires no packet-level tooling of its own.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| PacketInspector | Fabric | 1.20.1 – 1.21.11 | Client-side only | 2026-02-03 |
| Instant Replay Mod | Fabric | 1.20 – 1.21.11 | Client-side only | 2026-03-30 |
| Packet Ninja | Fabric | 1.21.8 – 1.21.11 | Client-side only | 2026-03-28 |
| Format | Fabric | 1.20 – 1.21.3 | Not published | 2024-10-22 |
Questions
Does PacketInspector need Fabric API?
Does a server need PacketInspector?
Which game versions does PacketInspector cover?
In the catalog
PacketInspector is one of 8,499 Technology mods on ModsFinder, and one of 4,201 Technology mods for Fabric. 19,862 mods support Minecraft 1.21.11.
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What the author says
PacketInspector is a developer‑focused in‑game tool for analyzing Minecraft’s client‑side network packets. It provides real‑time packet monitoring, structured field inspection, NBT viewing, and raw Java/JSON representations to support debugging and protocol research.
Official listing
- Modrinth page
- modrinth.com/mod/packetinspector
- Owner
- QURATOR
- Published
- 2026-02-01
- Updated on Modrinth
- 2026-02-03
- Facts verified
- 2026-10-15