#serialization #bencode #bittorrent #serde #torrent

no-std bt_bencode

A Bencode encoding/decoding implementation

3 unstable releases

new 0.8.1 May 15, 2024
0.8.0 Jan 1, 2024
0.7.0 Jul 31, 2022
0.6.0 Mar 21, 2022
0.2.0 Feb 20, 2020

#226 in Encoding

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Used in 4 crates




BtBencode is a library which can help with Bencode encoding/decoding. Bencode is primarily used in BitTorrent related applications.

It uses the Serde library to serialize and deserialize Bencode data. It is similar to Serde JSON in terms of functionality and implementation.


An example serializing a standard Rust collection type and then deserializing into a custom type:

use std::collections::BTreeMap;
use serde_derive::Deserialize;

let mut dict: BTreeMap<String, String> = BTreeMap::new();
dict.insert(String::from("url"), String::from("https://example.com/"));

let serialized_bytes = bt_bencode::to_vec(&dict)?;

struct Info<'a> {
    url: &'a str,

let info: Info = bt_bencode::from_slice(&serialized_bytes)?;
assert_eq!(info.url, "https://example.com/");

An example deserializing from a slice of bytes into a general Value representation and then from the Value instance into a more strongly typed data structure.

use serde_derive::{Serialize, Deserialize};

use bt_bencode::Value;

#[derive(Serialize, Deserialize)]
struct Info {
    t: String,
    url: String,

let serialized_bytes = bt_bencode::to_vec(&Info {
    t: String::from("query"),
    url: String::from("https://example.com/"),

let value: Value = bt_bencode::from_slice(&serialized_bytes)?;
assert_eq!(value["t"].as_str().unwrap(), "query");
    value.get("url").and_then(|url| url.as_str()).unwrap(),

let info: Info = bt_bencode::from_value(value)?;
assert_eq!(info.t, "query");
assert_eq!(info.url, "https://example.com/");


cargo add bt_bencode

By default, the std feature is enabled.

Alloc only

If the host environment has an allocator but does not have access to the Rust std library:

cargo add --no-default-features --features alloc bt_bencode


Licensed under either of Apache License, Version 2.0 or MIT License at your option.


Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.