McProtoNet is a .NET library for the Minecraft Java Edition protocol, client side. It gives you the transport, the packets, and a simple client. You write the bot.

Bots join a server, listen to game chat, and walk into any text you type. The picture shows 117 of them. This is examples/FormationBots — a few hundred lines on top of the library.

⚠️ McProtoNet is under active development. The API changes between versions, and not all packets are modeled yet.

What is inside

• Transport. MinecraftConnection frames packets over any duplex Stream on System.IO.Pipelines. Compression is libdeflate, encryption is AES/CFB8 with hardware cores for x86 (AES-NI) and ARM64 (NEON). The cipher beats BouncyCastle by about 2x in our benchmarks and allocates nothing per call.
• Packets. Typed packet classes for protocols 735–776 (Minecraft 1.16 → 26.2), generated from F# specs. One allocation per packet, no reflection, no boxing on the hot path. Unknown packets stay available as raw id + bytes.
• Client. MinecraftClient connects over TCP, resolves SRV records, and moves packets. It also finds LAN servers. Handshake, login, and game logic stay in your code — the examples show the whole path.
• NBT. A standalone reader and writer for the NBT format, with Modified UTF-8 strings.
• Works with offline-mode servers. Mojang authentication is not implemented yet.

Install

dotnet add package McProtoNet

The package pulls in the rest of the stack. You can also take a single layer:

Package	What it holds
McProtoNet	Client glue: connect, SRV lookup, typed send, LAN search
McProtoNet.Protocol	Generated packets, types, and handler bases
McProtoNet.Transport	Framing, compression, encryption
McProtoNet.Primitives	VarInt readers and writers, packet structs
McProtoNet.NBT	NBT reader and writer

The transport depends on the native package McProtoNet.Native 1.0.0, which carries libdeflate.

Nightly builds

Every push to the dev branch publishes packages to a Feedz feed. Versions look like 2.0.0-preview.4.<height> and are prerelease, so --prerelease is needed. Stable releases go to nuget.org.

dotnet nuget add source https://f.feedz.io/mcprotonet/night/nuget/index.json -n mcprotonet-night
dotnet add package McProtoNet --prerelease

Quick start

using McProtoNet;
using HandshakeSb = McProtoNet.Protocol.Packets.Handshaking.Serverbound;
using LoginSb = McProtoNet.Protocol.Packets.Login.Serverbound;

const int Pv = 772;

await using var client = new MinecraftClient(new MinecraftClientOptions { Host = "localhost" });
await client.ConnectAsync();

await client.SendAsync(new HandshakeSb.SetProtocolPacket(Pv, "localhost", 25565, 2), Pv);
await client.SendAsync(new LoginSb.LoginStartPacket("Steve", V764_Last: new(Guid.NewGuid())), Pv);

await foreach (var packet in client.ReadPacketsAsync())
{
    // bot derives from ClientboundHandler and overrides the packets it wants
    await bot.HandleAsync(in packet, Pv);
}

The receive loop and the phase machine live in your code on purpose. examples/MinimalBot walks the full path in one file: handshake → login → configuration → play, with keep-alives and chat. examples/FormationBots runs one client per bot in the picture above.

Versions

Minecraft	1.16 → 26.2 (protocols 735–776)
Runtime	.NET 8, .NET 9, .NET 10, .NET 11

License

MIT. See LICENSE.

Community

Questions, bugs, ideas: Discord or GitHub issues.

💸 Support the project

You can support development with crypto. Send only in the network named next to the address; a transfer that arrives through another network cannot be returned. None of the addresses needs a memo or a tag.

USDT, TRON network (TRC-20): TVw4jCehZspPk3aT1fecQWhEzH2LEkG9WG

TON and USDT, TON network: UQDp_mDSj3VH0uIqBl2aNsyZJ8Drymo3qX-nlYNr5r6zTCaI

BTC, Bitcoin network: bc1q3ushl443q9xvclxtqxcvltdd64ffy3h8x7xsm4

The same is on the site: Support the project.