# ls-qpack
[](https://crates.io/crates/ls-qpack)
[](https://docs.rs/ls-qpack)
**QPACK**: Field Compression for HTTP/3
([*RFC 9204*](https://datatracker.ietf.org/doc/rfc9204/))
Rust implementation based on [ls-qpack](https://github.com/litespeedtech/ls-qpack)
## Introduction
QPACK is a compressor for headers data used by [HTTP/3](https://en.wikipedia.org/wiki/HTTP/3).
It allows correctness in the presence of out-of-order delivery,
with flexibility for implementations to balance between resilience against
head-of-line blocking and optimal compression ratio.
## Example
```rust
use ls_qpack::decoder::Decoder;
use ls_qpack::encoder::Encoder;
use ls_qpack::StreamId;
const HEADERS: [(&str, &str); 2] = [(":status", "404"), ("foo", "bar")];
fn main() {
let (encoded_headers, _) = Encoder::new()
.encode_all(StreamId::new(0), HEADERS)
.unwrap()
.into();
let decoded_headers = Decoder::new(0, 0)
.decode(StreamId::new(0), encoded_headers)
.unwrap()
.take()
.unwrap();
println!("Decoded header: {:?}", decoded_headers);
}
```