Packet is an on-chain messaging and order protocol built on Solana. It combines end-to-end encryption, payment gating, compressed state via Light Protocol, and permanent off-chain storage via Irys — letting wallets, apps, and agents send verifiable, private messages without a centralized server.
Packet supports 1:1 messaging and end-to-end encrypted group chat. Group chat uses BGW broadcast encryption over BLS12-381: a single epoch key is distributed to every member through a compact on-chain header instead of re-encrypting each message per recipient, and members recover access from nothing but their Solana wallet — no key server, no local state, no per-recipient message copies.
See full documentation at docs.xpkt.dev.
packet/
|-- sdk/ # TypeScript SDK (xpkt-sdk)
|-- cli/ # CLI tool (xpkt-cli - packet binary)
|-- mcp/ # MCP server (xpkt-mcp - packet-mcp binary)
`-- wasm/ # BLS12-381 BGW broadcast-encryption engine (WebAssembly)
| Package | Use it when |
|---|---|
xpkt-sdk (sdk/) |
You are building a TypeScript app, service, bot, or integration directly on Packet. |
xpkt-cli (cli/) |
A human wants terminal commands for config, messages, rooms, inboxes, crypto, and upload. |
xpkt-mcp (mcp/) |
An MCP agent host needs Packet tools, resources, upload, and encryption. |
WASM engine (wasm/) |
You need the BGW broadcast-encryption primitive that powers group chat. |
sdk/: TypeScript SDK
Package: xpkt-sdk — works in the browser (wallet adapter) and Node.js (Keypair).
npm install xpkt-sdkcli/: CLI
Package: xpkt-cli | Binary: packet
npm install -g xpkt-climcp/: MCP server
Package: xpkt-mcp | Binary: packet-mcp
npx -y xpkt-mcpAn on-chain account owned by a wallet that acts as a directory of incoming threads. Inboxes can enforce a payment rule: senders must include a minimum SOL payment to open a thread. Multiple inboxes per wallet are supported.
The conversation container between two wallets, created by the sender alongside the first message. Both parties append messages. Threads optionally hold an escrow balance.
The container for encrypted group chat. An admin creates a room and adds or removes members; each member is assigned a slot. Messages are encrypted once under a per-epoch key that BGW broadcast encryption distributes to all current members through a compact, immutable on-chain header. Membership changes rotate the epoch and are recorded as a checkpoint/delta chain in the headers, so a member reconstructs the recipient set and recovers keys from chain state alone. New members cannot read history; removed members cannot read future messages.
A single entry in a thread or room. Carries a content type (text, url, irys, ipfs, or arweave) and a content field. Large or sensitive payloads are uploaded to Irys (or another store) and the message carries the pointer; clients resolve and decrypt it on read.
1:1 messages are encrypted with X25519 Diffie-Hellman before leaving the sender, with one or more readers. Group messages are encrypted under the room's broadcast epoch key. Wallets can use a deterministic wallet-derived key or register a separate Key account on-chain; raw-keypair clients (CLI, MCP, server) need no registration, while browser-wallet users register a key once.
Inbox owners can enable escrow: incoming payments are held in a per-thread escrow account until the receiver approves and withdraws.
import { PacketClient, PacketWallet } from "xpkt-sdk";
const adminClient = new PacketClient({ wallet: PacketWallet.fromKeypair(admin), connection });
// Admin creates a room and adds members.
const { client: room } = await adminClient.createRoom({ signMessage });
await room.addMember({ member: alice });
await room.addMember({ member: bob });
// Members send and read from just their wallet + RPC.
const aliceRoom = await aliceClient.room({ id: room.address });
await aliceRoom.messages().send({ text: "gm" });
const bobRoom = await bobClient.room({ id: room.address });
const messages = await bobRoom.loadMessages({ limit: 50 });The same flow is available from the CLI (packet room create | add | send | read) and the MCP server (packet_room_*).
packet config init --rpc https://devnet.helius-rpc.com/?api-key=YOUR_KEY --keypair ~/.config/solana/id.json
packet message new-thread --to <pubkey> --text "Hello"Message send commands default to encrypt + upload; pass --no-encrypt or --no-upload only when plaintext or inline behavior is intentional.
Group chat relies on a global BGW parameter artifact (powers of a setup secret over BLS12-381), generated once and reused by every room. The SDK resolves it from a configurable source and ships a hosted Arweave-style default; override it with configureDefaultBgwParams({ baseUrl }).
Packet requires a ZK Compression / Photon-compatible RPC; a standard-only Solana RPC is not enough, because Packet reads and writes compressed accounts. Helius is the simplest setup:
https://mainnet.helius-rpc.com/?api-key=YOUR_KEY
https://devnet.helius-rpc.com/?api-key=YOUR_KEY
See RPC and Photon for details.
Packet is not gasless. Sending messages and creating threads are Solana transactions and can cost up to about 0.00005 SOL. Creating an inbox costs more because it opens on-chain account state, but a custom inbox is not required for basic communication.
Keep raw content out of the compressed message account: use pointers for anything larger than about 128 bytes, otherwise transactions can fail from size/compute limits. Irys is the recommended store for durable encrypted bodies; you can also use IPFS, Arweave, HTTPS, or a custom server. The receiver fetches the stored link, so if the source disappears the on-chain message remains while the body becomes unreadable.
A3YNvikE96zn2PYrbqRa8hheH99ks7qt22zQiUF8Ttao — Packet main program (inboxes, threads, messages, rooms, keys, users) on mainnet and devnet.
APACHE 2.0