notepack

notepack is a Rust library and CLI for encoding and decoding nostr notes into a compact binary format.

It ships with:

• 📦 A Rust crate — for embedding notepack logic into apps, relays, or tooling.
• 💻 A CLI tool — for piping JSON ↔ notepack_… strings in scripts.

🚀 What is notepack?

notepack is a binary serialization for Nostr “events” (Note), plus a recognizable string form. It aims to:

• Shrink payloads using unsigned LEB128 (“varint”) integers.
• Store note fields (id, pubkey, sig) and hex tag payloads as raw bytes.
• Preserve UTF‑8 for text fields.
• Provide a copy‑pasteable string starting with notepack_ + Base64 (RFC 4648, no padding).

📜 See SPEC.md for the full format specification.

✨ Features

• ✅ CLI tool: Turn JSON Nostr events into compact strings or back again.
• ✅ Compact: Every integer is ULEB128 varint, tags are tagged‑varint.
• ✅ 50% size reduction Many large events like contact lists see a 50% reduction in size
• ✅ Simple So simple, I'm proposing it as the candidate for nostr's canonical binary representation
• ✅ Streaming parser: No massive allocations; parse incrementally.

Example

$ notepack <<<'{"id": "f1e7bc2a9756453fcc0e80ecf62183fa95b9a1278a01281dbc310b6777320e80","pubkey": "7fe437db5884ee013f701a75f8d1a84ecb434e997f2a31411685551ffff1b841","created_at": 1753900182,"kind": 1,"tags": [],"content": "hi","sig": "75507f84d78211a68f2f964221f5587aa957a66c1941d01125caa07b9aabdf5a98c3e63d1fe1e307cbf01b74b0a1b95ffe636eb6746c00167e0d48e5b11032d5"}'

notepack_AfHnvCqXVkU/zA6A7PYhg/qVuaEnigEoHbwxC2d3Mg6Af+Q321iE7gE/cBp1+NGoTstDTpl/KjFBFoVVH//xuEF1UH+E14IRpo8vlkIh9Vh6qVembBlB0BElyqB7mqvfWpjD5j0f4eMHy/AbdLChuV/+Y262dGwAFn4NSOWxEDLVlsmpxAYBAmhpAA

• json string: 363 bytes
• notepack string: 124 bytes raw, 196 base64-encoded

For large contact lists, you can crunch them down from 74kb to about 36kb.

📦 Usage (Library)

Encoding

use notepack::{Note, pack_note_to_string};

let note = Note {
    id: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa".into(),
    pubkey: "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb".into(),
    created_at: 1753898766,
    kind: 1,
    tags: vec![vec!["tag".into(), "value".into()]],
    content: "Hello, world!".into(),
    sig: "cccc...".into(),
};

let encoded = pack_note_to_string(&note).unwrap();
println!("{encoded}"); // => notepack_AAECAw...

Streaming Decode

use notepack::{NoteParser, ParsedField};

let b64 = "notepack_..."; // from wire
let bytes = NoteParser::decode(b64).unwrap();
let parser = NoteParser::new(&bytes);

for field in parser {
    match field.unwrap() {
        ParsedField::Id(id) => println!("id: {}", hex::encode(id)),
        ParsedField::Content(c) => println!("content: {}", c),
        _ => {}
    }
}

💻 CLI Usage

The binary is also called notepack.

Encode JSON → notepack string

echo '{"id":"...","pubkey":"...","created_at":123,"kind":1,"tags":[],"content":"Hi","sig":"..."}' \
  | notepack

Decode notepack string → JSON

echo 'notepack_AAECA...' | notepack

📂 Project Structure

src
├── SPEC.md         # Full binary format spec
├── error.rs        # Unified error type for encoding/decoding
├── lib.rs          # Crate entrypoint
├── main.rs         # CLI tool: JSON ↔ notepack
├── note.rs         # `Note` struct (Nostr event model)
├── parser.rs       # Streaming `NoteParser`
├── stringtype.rs   # String vs raw byte tags
└── varint.rs       # LEB128 varint helpers

📜 License

MIT — do whatever you want, but attribution is appreciated.