A JSON Schema validator implementation. It compiles schema into a validation tree to have validation as fast as possible.

Supported drafts:

• Draft 7 (except optional idn-hostname.json, float_overflow.json and format_email.json test cases)
• Draft 6 (except optional float_overflow.json and format_email.json test cases)
• Draft 4 (except optional bignum.json, float_overflow.json and format_email.json test cases)

# Cargo.toml
jsonschema = "0.6"

To validate documents against some schema and get validation errors (if any):

use jsonschema::{JSONSchema, Draft, CompilationError};
use serde_json::json;

fn main() -> Result<(), CompilationError> {
    let schema = json!({"maxLength": 5});
    let instance = json!("foo");
    let compiled = JSONSchema::compile(&schema)?;
    let result = compiled.validate(&instance);
    if let Err(errors) = result {
        for error in errors {
            println!("Validation error: {}", error)
        }
    }
    Ok(())
}

If you only need to know whether document is valid or not (which is faster):

use jsonschema::is_valid;
use serde_json::json;

fn main() {
    let schema = json!({"maxLength": 5});
    let instance = json!("foo");
    assert!(is_valid(&schema, &instance));
}

Or use a compiled schema (preferred):

use jsonschema::{JSONSchema, Draft, CompilationError};
use serde_json::json;

fn main() -> Result<(), CompilationError> {
    let schema = json!({"maxLength": 5});
    let instance = json!("foo");
    // Draft is detected automatically
    // with fallback to Draft7
    let compiled = JSONSchema::compile(&schema)?;
    assert!(compiled.is_valid(&instance));
    Ok(())
}

• Python - See the ./bindings/python directory
• Ruby - a crate by @driv3r

There is a comparison with other JSON Schema validators written in Rust - jsonschema_valid==0.4.0 and valico==3.5.0.

Test machine i8700K (12 cores), 32GB RAM.

Schemas & input values:

• Big valid input. It is an Open API 2.0 schema for Kubernetes which is ~3.15 MB (kubernetes.json and swagger.json files)
• Small valid input (small_schema.json and small_valid.json)
• Small invalid input (small_schema.json and small_invalid.json)

Ratios are given against compiled JSONSchema using its validate. The is_valid method is faster, but gives only a boolean return value:

Unfortunately, jsonschema_valid mistakenly considers the Kubernetes Open API schema as invalid and therefore can't be compared with other libraries in this case.

You can find benchmark code in benches/jsonschema.rs, Rust version is 1.49.

NOTE. This library is in early development.

If you have anything to discuss regarding this library, please, join our gitter!