Expand description


Find out the path at which a deserialization error occurred. This crate provides a wrapper that works with any existing Serde Deserializer and exposes the chain of field names leading to the error.


use serde::Deserialize;
use std::collections::BTreeMap as Map;

struct Package {
    name: String,
    dependencies: Map<String, Dependency>,

struct Dependency {
    version: String,

fn main() {
    let j = r#"{
        "name": "demo",
        "dependencies": {
            "serde": {
                "version": 1

    // Some Deserializer.
    let jd = &mut serde_json::Deserializer::from_str(j);

    let result: Result<Package, _> = serde_path_to_error::deserialize(jd);
    match result {
        Ok(_) => panic!("expected a type error"),
        Err(err) => {
            let path = err.path().to_string();
            assert_eq!(path, "dependencies.serde.version");


  • Deserializer adapter that records path to deserialization errors.
  • Original deserializer error together with the path at which it occurred.
  • Path to the error value in the input, like dependencies.serde.typo1.
  • Iterator over segments of a path.
  • Serializer adapter that records path to serialization errors.
  • State for bookkeeping across nested deserializer calls.