diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..57872d0
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/vendor/
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..dc1f982
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,20 @@
+{
+    "name": "knplabs/json-schema",
+    "description": "PHP json-schema implementation",
+    "type": "library",
+    "license": "MIT",
+    "autoload": {
+        "psr-4": {
+            "Knplabs\\JsonSchema\\": "src/"
+        }
+    },
+    "authors": [
+        {
+            "name": "KnpLabs",
+            "email": "hello@knplabs.com"
+        }
+    ],
+    "require": {
+        "php": ">=8.0"
+    }
+}
diff --git a/src/Collection.php b/src/Collection.php
new file mode 100644
index 0000000..3af4156
--- /dev/null
+++ b/src/Collection.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace KnpLabs\JsonSchema;
+
+use Exception;
+
+final class Collection
+{
+    /**
+     * @param iterable<JsonSchema<mixed>> $schemas
+     */
+    public function __construct(private iterable $schemas)
+    {
+    }
+
+    /**
+     * @template J of JsonSchema
+     *
+     * @param class-string<J> $schemaClassName
+     *
+     * @return J
+     */
+    public function get(string $schemaClassName): JsonSchema
+    {
+        foreach ($this->schemas as $schema) {
+            if (is_a($schema, $schemaClassName)) {
+                return $schema;
+            }
+        }
+
+        throw new Exception("Schema {$schemaClassName} not found.");
+    }
+}
diff --git a/src/CollectionSchema.php b/src/CollectionSchema.php
new file mode 100644
index 0000000..b383db0
--- /dev/null
+++ b/src/CollectionSchema.php
@@ -0,0 +1,74 @@
+<?php
+
+declare(strict_types=1);
+
+namespace KnpLabs\JsonSchema;
+
+/**
+ * @template I
+ *
+ * @phpstan-type CollectionSchemaData array<I>
+ *
+ * @extends JsonSchema<CollectionSchemaData>
+ */
+abstract class CollectionSchema extends JsonSchema
+{
+    /**
+     * @param JsonSchema<I> $itemSchema
+     */
+    public function __construct(private JsonSchema $itemSchema)
+    {
+    }
+
+    public function getExamples(): iterable
+    {
+        yield [...$this->itemSchema->getExamples()];
+    }
+
+    public function getTitle(): string
+    {
+        return sprintf('Collection<%s>', $this->itemSchema->getTitle());
+    }
+
+    protected function getUniqueItems(): ?bool
+    {
+        return null;
+    }
+
+    protected function getMinLength(): ?int
+    {
+        return null;
+    }
+
+    protected function getMaxLength(): ?int
+    {
+        return null;
+    }
+
+    protected function getRange(): ?int
+    {
+        return null;
+    }
+
+    protected function getSchema(): array
+    {
+        $schema = [
+            'type' => 'array',
+            'items' => $this->itemSchema->jsonSerialize(),
+        ];
+
+        if (null !== $uniqueItems = $this->getUniqueItems()) {
+            $schema['uniqueItems'] = $uniqueItems;
+        }
+
+        if (null !== $minLength = $this->getMinLength()) {
+            $schema['minLength'] = $minLength;
+        }
+
+        if (null !== $maxLength = $this->getMaxLength()) {
+            $schema['maxLength'] = $maxLength;
+        }
+
+        return $schema;
+    }
+}
diff --git a/src/EnumSchema.php b/src/EnumSchema.php
new file mode 100644
index 0000000..02fbb5b
--- /dev/null
+++ b/src/EnumSchema.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace KnpLabs\JsonSchema;
+
+/**
+ * @template E
+ * @extends JsonSchema<E>
+ */
+abstract class EnumSchema extends JsonSchema
+{
+    public function getExamples(): iterable
+    {
+        return $this->getEnum();
+    }
+
+    protected function getSchema(): array
+    {
+        return [
+            'enum' => [...$this->getEnum()],
+        ];
+    }
+
+    /**
+     * @return iterable<int, E>
+     */
+    abstract protected function getEnum(): iterable;
+}
diff --git a/src/JsonSchema.php b/src/JsonSchema.php
new file mode 100644
index 0000000..87a628b
--- /dev/null
+++ b/src/JsonSchema.php
@@ -0,0 +1,260 @@
+<?php
+
+declare(strict_types=1);
+
+namespace KnpLabs\JsonSchema;
+
+use JsonSerializable;
+
+/**
+ * @template T of mixed
+ */
+abstract class JsonSchema implements JsonSerializable
+{
+    /**
+     * @param JsonSchema<E> $schema
+     * @template E of mixed
+     *
+     * @return JsonSchema<null|E>
+     */
+    public static function nullable(self $schema): self
+    {
+        return self::create(
+            '',
+            '',
+            [...$schema->getExamples(), null],
+            ['oneOf' => [self::null(), $schema->jsonSerialize()]],
+        );
+    }
+
+    /**
+     * @param iterable<int, E>     $examples
+     * @param array<string, mixed> $schema
+     * @template E of mixed
+     *
+     * @return JsonSchema<E>
+     */
+    public static function create(
+        string $title,
+        string $description,
+        iterable $examples,
+        $schema
+    ): self {
+        return new class($title, $description, $examples, $schema) extends JsonSchema {
+            /**
+             * @var iterable<int, E>
+             */
+            private readonly iterable $examples;
+
+            /**
+             * @param iterable<int, E>     $examples
+             * @param array<string, mixed> $schema
+             */
+            public function __construct(
+                private string $title,
+                private string $description,
+                iterable $examples,
+                private $schema
+            ) {
+                $this->examples = [...$examples];
+            }
+
+            public function getTitle(): string
+            {
+                return $this->title;
+            }
+
+            public function getDescription(): string
+            {
+                return $this->description;
+            }
+
+            /**
+             * @return iterable<int, E>
+             */
+            public function getExamples(): iterable
+            {
+                yield from $this->examples;
+            }
+
+            protected function getSchema(): array
+            {
+                return $this->schema;
+            }
+        };
+    }
+
+    /**
+     * @template I
+     *
+     * @param JsonSchema<I> $jsonSchema
+     *
+     * @return JsonSchema<array<int, I>>
+     */
+    public static function collection(self $jsonSchema): self
+    {
+        return self::create(
+            sprintf('Collection<%s>', $jsonSchema->getTitle()),
+            '',
+            [[...$jsonSchema->getExamples()]],
+            [
+                'type' => 'array',
+                'items' => $jsonSchema,
+            ]
+        );
+    }
+
+    /**
+     * @return array<string, mixed>&array{title: string, description: string, examples: array<T>}
+     */
+    public function jsonSerialize(): mixed
+    {
+        $schema = $this->getSchema();
+
+        /**
+         * @var array<string, mixed>&array{title: string, description: string, examples: array<T>}
+         */
+        return array_merge(
+            $schema,
+            [
+                'title' => $this->getTitle(),
+                'description' => $this->getDescription(),
+                'examples' => [...$this->getExamples()],
+            ],
+        );
+    }
+
+    /**
+     * @return iterable<int, T>
+     */
+    abstract public function getExamples(): iterable;
+
+    public function getTitle(): string
+    {
+        return '';
+    }
+
+    public function getDescription(): string
+    {
+        return '';
+    }
+
+    /**
+     * @param scalar $value
+     *
+     * @return array<string, mixed>
+     */
+    protected static function constant($value): array
+    {
+        return [
+            'const' => $value,
+        ];
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    protected static function null(): array
+    {
+        return [
+            'type' => 'null',
+        ];
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    protected static function text(): array
+    {
+        return [
+            'type' => 'string',
+            'minLength' => 1,
+        ];
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    protected static function boolean(): array
+    {
+        return [
+            'type' => 'boolean',
+        ];
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    protected static function string(?string $format = null): array
+    {
+        $result = [
+            ...self::text(),
+            'maxLength' => 255,
+        ];
+
+        if (null !== $format) {
+            $result['format'] = $format;
+        }
+
+        return $result;
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    protected static function integer(): array
+    {
+        return [
+            'type' => 'integer',
+        ];
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    protected static function number(): array
+    {
+        return [
+            'type' => 'number',
+        ];
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    protected static function date(): array
+    {
+        return [
+            'type' => 'string',
+            'format' => 'date',
+        ];
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    protected static function positiveInteger(): array
+    {
+        return [
+            ...self::integer(),
+            'exclusiveMinimum' => 0,
+        ];
+    }
+
+    /**
+     * @param array<string, mixed> ...$schemas
+     *
+     * @return array{oneOf: array<array<string, mixed>>}
+     */
+    protected static function oneOf(...$schemas): array
+    {
+        return [
+            'oneOf' => $schemas,
+        ];
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    abstract protected function getSchema(): array;
+}
diff --git a/src/ObjectSchema.php b/src/ObjectSchema.php
new file mode 100644
index 0000000..2e43ddd
--- /dev/null
+++ b/src/ObjectSchema.php
@@ -0,0 +1,71 @@
+<?php
+
+declare(strict_types=1);
+
+namespace KnpLabs\JsonSchema;
+
+/**
+ * @template T of array<string, mixed>
+ * @extends JsonSchema<T>
+ */
+abstract class ObjectSchema extends JsonSchema
+{
+    /**
+     * @var array<string, JsonSchema<mixed>>
+     */
+    private array $properties = [];
+
+    /**
+     * @var array<string>
+     */
+    private array $required = [];
+
+    public function getExamples(): iterable
+    {
+        /**
+         * @var T
+         */
+        $object = [];
+
+        foreach ($this->properties as $name => $property) {
+            foreach ($property->getExamples() as $example) {
+                $object[$name] = $example;
+
+                continue 2;
+            }
+        }
+
+        yield $object;
+    }
+
+    protected function hasAdditionalProperties(): bool
+    {
+        return false;
+    }
+
+    /**
+     * @template S
+     *
+     * @param JsonSchema<S> $schema
+     */
+    protected function addProperty(string $name, JsonSchema $schema, bool $required = true): void
+    {
+        $this->properties[$name] = $schema;
+
+        if ($required) {
+            $this->required[] = $name;
+        } else {
+            $this->required = array_diff($this->required, [$name]);
+        }
+    }
+
+    protected function getSchema(): array
+    {
+        return [
+            'type' => 'object',
+            'additionalProperties' => $this->hasAdditionalProperties(),
+            'properties' => $this->properties,
+            'required' => $this->required,
+        ];
+    }
+}
diff --git a/src/Scalar/UuidSchema.php b/src/Scalar/UuidSchema.php
new file mode 100644
index 0000000..227521f
--- /dev/null
+++ b/src/Scalar/UuidSchema.php
@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+namespace KnpLabs\JsonSchema\Scalar;
+
+use KnpLabs\JsonSchema\JsonSchema;
+
+/**
+ * @extends JsonSchema<string>
+ */
+final class UuidSchema extends JsonSchema
+{
+    private const PATTERN = '^[0-9a-f]{8}(-[0-9a-f]{4}){3}-[0-9a-f]{12}$';
+
+    /**
+     * {@inheritDoc}
+     */
+    public function getExamples(): iterable
+    {
+        yield '123e4567-e89b-12d3-a456-426614174000';
+    }
+
+    public function getTitle(): string
+    {
+        return 'Universally unique identifier';
+    }
+
+    public function getDescription(): string
+    {
+        return 'A universally unique identifier (UUID) is a 128-bit label used for information in computer systems.';
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    protected function getSchema(): array
+    {
+        return array_merge(
+            self::string(),
+            [
+                'pattern' => self::PATTERN,
+                'minLength' => 36,
+                'maxLength' => 36,
+            ]
+        );
+    }
+}
diff --git a/src/Validator.php b/src/Validator.php
new file mode 100644
index 0000000..289a6b7
--- /dev/null
+++ b/src/Validator.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace KnpLabs\JsonSchema;
+
+use KnpLabs\JsonSchema\Validator\Errors;
+
+interface Validator
+{
+    /**
+     * @template T
+     *
+     * @param T                                         $data
+     * @param class-string<JsonSchema<T>>|JsonSchema<T> $schema
+     */
+    public function validate($data, $schema): ?Errors;
+}
diff --git a/src/Validator/Error.php b/src/Validator/Error.php
new file mode 100644
index 0000000..7c978e1
--- /dev/null
+++ b/src/Validator/Error.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace KnpLabs\JsonSchema\Validator;
+
+final class Error
+{
+    public function __construct(
+        private string $path,
+        private string $message
+    ) {
+    }
+
+    public function getPath(): string
+    {
+        return $this->path;
+    }
+
+    public function getMessage(): string
+    {
+        return $this->message;
+    }
+}
diff --git a/src/Validator/Errors.php b/src/Validator/Errors.php
new file mode 100644
index 0000000..c53b6a4
--- /dev/null
+++ b/src/Validator/Errors.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace KnpLabs\JsonSchema\Validator;
+
+use ArrayIterator;
+use Countable;
+use Iterator;
+use IteratorAggregate;
+
+/**
+ * @implements IteratorAggregate<Error>
+ */
+final class Errors implements Countable, IteratorAggregate
+{
+    /**
+     * @var array<Error>
+     */
+    private array $errors;
+
+    public function __construct(Error ...$errors)
+    {
+        $this->errors = $errors;
+    }
+
+    public function count(): int
+    {
+        return \count($this->errors);
+    }
+
+    /**
+     * @return ArrayIterator<int, Error>
+     */
+    public function getIterator(): Iterator
+    {
+        return new ArrayIterator($this->errors);
+    }
+}