Philiprehberger.JsonSchema

Validate JSON documents against JSON Schema with structured error paths using System.Text.Json.

Installation

dotnet add package Philiprehberger.JsonSchema

Usage

using Philiprehberger.JsonSchema;

var schema = JsonSchema.Parse("""
{
    "type": "object",
    "properties": {
        "name": { "type": "string", "minLength": 1 },
        "age": { "type": "integer", "minimum": 0 }
    },
    "required": ["name"]
}
""");

var result = schema.Validate("""{ "name": "Alice", "age": 30 }""");
Console.WriteLine(result.IsValid); // True

Handling Validation Errors

var result = schema.Validate("""{ "age": -5 }""");

foreach (var error in result.Errors)
{
    Console.WriteLine($"{error.Path}: {error.Message} ({error.Keyword})");
    // $.name: Required property is missing (required)
    // $.age: Value is less than minimum of 0 (minimum)
}

String Validation

using Philiprehberger.JsonSchema;

var schema = JsonSchema.Parse("""
{
    "type": "string",
    "minLength": 1,
    "maxLength": 100,
    "pattern": "^[A-Za-z]+$",
    "format": "email"
}
""");

Supported formats: email, date-time, uri, ipv4, ipv6.

Array Validation

using Philiprehberger.JsonSchema;

var schema = JsonSchema.Parse("""
{
    "type": "array",
    "items": { "type": "string" },
    "minItems": 1,
    "maxItems": 10,
    "uniqueItems": true
}
""");

Enum and Const

using Philiprehberger.JsonSchema;

var schema = JsonSchema.Parse("""
{
    "type": "object",
    "properties": {
        "status": { "enum": ["active", "inactive", "pending"] },
        "version": { "const": 2 }
    }
}
""");

Schema Composition

using Philiprehberger.JsonSchema;

var schema = JsonSchema.Parse("""
{
    "oneOf": [
        { "type": "string", "maxLength": 5 },
        { "type": "integer", "minimum": 0 }
    ]
}
""");

Supports allOf (all must match), anyOf (at least one), oneOf (exactly one), and not (must not match).

$ref with $defs

using Philiprehberger.JsonSchema;

var schema = JsonSchema.Parse("""
{
    "type": "object",
    "properties": {
        "home": { "$ref": "#/$defs/Address" },
        "work": { "$ref": "#/$defs/Address" }
    },
    "$defs": {
        "Address": {
            "type": "object",
            "properties": {
                "street": { "type": "string" },
                "city": { "type": "string" }
            },
            "required": ["street", "city"]
        }
    }
}
""");

Static Validation

using Philiprehberger.JsonSchema;

var result = JsonSchema.Validate(schemaJson, documentJson);

API

Method	Description
JsonSchema.Parse(string)	Parse a JSON Schema string into a compiled schema
JsonSchema.Validate(string, string)	Validate a JSON document against a schema string
Schema.Validate(string)	Validate a JSON document string against a compiled schema
Schema.Validate(JsonNode?)	Validate a JsonNode against a compiled schema
ValidationResult.IsValid	Whether validation passed
ValidationResult.Errors	List of ValidationError with path, message, and keyword

Supported Keywords

Category	Keywords
Type	type
String	minLength, maxLength, pattern, format
Numeric	minimum, maximum
Array	items, minItems, maxItems, uniqueItems
Object	properties, required
Enum/Const	enum, const
Composition	allOf, anyOf, oneOf, not
References	$ref, $defs, definitions

Development

dotnet build src/Philiprehberger.JsonSchema.csproj --configuration Release

Support

If you find this project useful:

⭐ Star the repo

🐛 Report issues

💡 Suggest features

❤️ Sponsor development

🌐 All Open Source Projects

💻 GitHub Profile

🔗 LinkedIn Profile

License

MIT