The loader is used to produce a validatable schema by parsing the contents of a resolved schema.

A schema is parsed only once, and the result is cached.

So, why do we have to parse the schema contents? This is because different drafts contain different keywords, or the same keyword behaves differently in two distinct drafts. We also need to find all id’s inside a schema, to quickly resolve a reference the next time is needed.

use Opis\JsonSchema\{

// Option 1. - Get the loader from the validator

$validator = new Validator();
$loader = $validator->loader();

// Option 2. - Create the loader
$loader= new SchemaLoader();

// Validator constructor accepts a loader as argument
$validator = new Validator($loader);

// Or you can set the loader


Is used to resolve the contents of a schema by uri.

use Opis\JsonSchema\Validator;

$validator = new Validator();

// Get the resolver from schema loader
$resolver = $validator->loader()->resolver();

// Or, get it using the shortcut
$resolver = $validator->resolver();

registerRaw method

public function registerRaw(
    string|object|bool $schema,
    ?string $id = null
): bool

Use this method to register an inline raw schema. You can optionally set the id.

$resolver->registerRaw((object)['type' => 'object']);

$resolver->registerRaw('{"type": "object"}', '');

registerFile method

public function registerFile(string $id, string $file): self

Use this method to register a file as a schema. You must specify the id.

$resolver->regiserFile('', '/path/to/file.json');

registerPrefix method

public function registerPrefix(string $prefix, string $dir): self

Use this method to register a filesystem directory from where to load schema files. You must specify the id prefix.


In the above example we create a loader that maps the /path/to/dir directory to prefix.

Given that our dir contains


the following documents should be available, and should contain the contents of corresponding files


registerProtocol method

public function registerProtocol(string $scheme, callable $handler): self

Use this method to register a custom protocol handler.

use Opis\JsonSchema\Uri;

$resolver->registerProtocol('my-proto', function (Uri $uri) {
    // ...

The above example will handle all uris that have the my-proto scheme, such as my-proto://, my-proto://

registerProtocolDir method

public function registerProtocolDir(
    string $scheme, 
    string $host, 
    ?string $dir
): self

This method is similar to registerPrefix.

$resolver->registerProtocolDir('http', '', '/path/to/dir');

The files resolved from /path/to/dir will be prefixed with


Holds all registered drafts and keyword parsers. Used to create a validatable schema object from a source.

Also, contains different resolvers: filters, formats, media types, content encodings.

use Opis\JsonSchema\Validator;
use Opis\JsonSchema\Resolvers\{

$validator = new Validator();

// Get the parser from schema loader
$parser = $validator->loader()->parser();

// Or, by using the shortcut
$parser = $validator->parser();

// Accessing the resolvers...

/** @var FilterResolver $filter_resolver */
$filter_resolver = $parser->getFilterResolver();

/** @var FormatResolver $format_resolver */
$format_resolver = $parser->getFormatResolver();

/** @var ContentEncodingResolver $encoding_resolver */
$encoding_resolver = $parser->getContentEncodingResolver();

/** @var ContentMediaTypeResolver $media_resolver */
$media_resolver = $parser->getMediaTypeResolver();

Parser options

use Opis\JsonSchema\Validator;

$validator = new Validator();

// set an option
$validator->parser()->setOption($name, $value);

If you ever want to use only the features of json-schema (without the useful additions like filters or uri-templates), just use the settings from the “Vanilla” column.

Option Default Vanilla Description
defaultDraft "2020-12" "2020-12" Sets the default draft to use when $schema keyword is missing
decodeContent ["06", "07"] ["06", "07"] The draft versions where content related keywords are allowed: contentEncoding, contentMediaType, contentSchema. Use true to allow regardless of draft version.
allowFilters true false Enables/disables $filters keyword
allowFormats true true Enables/disables format keyword
allowMappers true false Enables/disables $map keyword
allowTemplates true false Enables/disables URI templates
allowGlobals true false Enables/disables $globals keyword
allowDefaults true false Enables/disables default keyword
allowSlots true false Enables/disables $slots keyword
allowPragmas true false Enables/disables $pragma keyword
allowDataKeyword true false Enables/disables $data keyword
allowUnevaluated true true Enables/disables unevaluatedProperties keyword and unevaluatedItems keyword
allowKeywordsAlongsideRef false false If set to true then siblings of $ref keyword are evaluated in draft-06 and draft-07. In other drafts this is enabled by default.
allowRelativeJsonPointerInRef true false If set to true then $ref keyword will use relative pointers if the value represents a relative pointer. In rare cases, this can collide with paths. (Since v2.1.0).
allowExclusiveMinMaxAsBool true false If set to true then exclusiveMinimum keyword and exclusiveMaximum keyword will allow booleans as value. (Since v2.1.0).
keepDependenciesKeyword true false If set to true then dependencies keyword will be available for draft-2019-09 and draft-2020-12. (Since v2.1.0).
keepAdditionalItemsKeyword true false If set to true then additionalItems keyword will be available for draft-2020-12. (Since v2.1.0).