#xtra #serialization #deserialization


A minimal serialization/deserialization library with expanded persistency functionality

28 stable releases (3 major)

5.0.2 Mar 10, 2023
5.0.1 Feb 26, 2023
4.15.0 Feb 15, 2023
2.1.1 Feb 9, 2023
1.0.5 Feb 6, 2023

#189 in Configuration

48 downloads per month
Used in logtra

Custom license

1.5K SLoC


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Contra is a configuration file loader for Rust.

The serialization/deserialization is heavily "inspired" (if not blatantly copied) from the serde crate. Special thanks to 'Josh Mcguigan' and his very helpful article Understanding-serde.


  • Load and save literals
    • string literals
    • numeric literals
    • enum literals
  • Load and save structs
    • primitive structs
    • nested structs
  • Load collections
    • vectors
    • maps
  • Support multiple File Formats
    • JSON
    • TOML
    • Cfg


Contra adds the derive macro: Serialize which implements the serialize method for the given struct. Contra adds the derive macro: Deserialize which implements the deserialize method for the given struct. These functions are best used via the Persistent trait which automatically implemented for all struct that are both Serializable, and Deserializable. The Persistent trait provides the functions load and save, which selects the appropiate serializer/deserializer based on the path given as parameter.


#[derive(Serialize, Deserialize, Default)]
pub struct Player {
    name: String,
    health: i32,
    dmg: f32,
    items: Vec<Item>,

#[derive(Deserialize, Deserialize)]
pub struct Item {
    name: String,
    slot: u32,
    stats: Vec<f32>,

fn main() {
    let saved_player = Player::default();
    player1::save("Player1.json").expect("failed to save player");

    let loaded_player = Player::load("Player1.json").expect("failed to load player");


~31K SLoC