saneyaml

Serde-first YAML for Rust — load config straight into your structs with #[derive(Deserialize)], with real YAML 1.2 semantics (so NO stays the string "NO", not false), useful diagnostics, and resource limits built in. Pure Rust, #![forbid(unsafe_code)].

Install

[dependencies]
saneyaml = "0.1"

Then use it:

use serde::{Deserialize, Serialize};

#[derive(Deserialize, Serialize)]
struct Config {
    name: String,
    port: u16,
}

fn main() -> Result<(), saneyaml::Error> {
    let cfg: Config = saneyaml::from_str("name: web\nport: 8080\n")?;
    assert_eq!(cfg.port, 8080);

    let text = saneyaml::to_string(&cfg)?;
    println!("{text}");
    Ok(())
}

Coming from the archived serde_yaml? It's close to a drop-in — see MIGRATION.md.

Why saneyaml

Most Rust YAML libraries make you pick one or the other: serde_yaml's ergonomics (now archived, and YAML 1.1-flavored), or a maintained YAML 1.2 parser like yaml-rust2 or saphyr that hands you a node tree to walk by hand. saneyaml is serde-first and YAML 1.2-correct.

Serde-first — from_str / from_slice / from_reader, to_string / to_writer, and a serde_yaml-style Value. Deserialize straight into your config structs — no hand-walking a node tree.
YAML 1.2 by default — correct scalar resolution, no "Norway problem": NO/on/off/yes stay strings. Opt into YAML 1.1 / serde_yaml-style resolution explicitly via schema modes (Core, Json, Failsafe, LegacySerdeYaml).
Diagnostics — line/column, in-document key path (e.g. server.port), and opt-in source-caret rendering.
Safe on hostile input — unsafe-free, with bounded time and memory: input-size, alias-expansion, nesting-depth, scalar-length, and collection-size limits.
Streaming and source-preserving edits — pull-based streaming (EventStream / DocumentStream) plus edit(...) for path-based config refactors that keep comments, anchors, ordering, and untouched bytes.
Benchmarked — real-world config corpus runs are tracked against serde_yaml, yaml-rust2, and saphyr; see BENCHMARKS.md.

Status

Pre-1.0 (0.2.0), MSRV Rust 1.88, and actively maintained. The public API is a preview surface but is treated as SemVer-visible: breaking changes and MSRV bumps are explicit, documented release decisions. The road to 1.0 is about locking the surface down, not expanding it — stability is the goal.

Documentation

MIGRATION.md — serde_yaml migration cookbook + support matrix
COMPATIBILITY.md — schema modes, scalar resolution, divergences, threat model
ARCHITECTURE.md — crate layout and design
BENCHMARKS.md · SECURITY.md · CONTRIBUTING.md · CHANGELOG.md

License