diff --git a/src/Adapter/AdapterInterface.php b/src/Adapter/AdapterInterface.php
index c040cec..8db6dd1 100644
--- a/src/Adapter/AdapterInterface.php
+++ b/src/Adapter/AdapterInterface.php
@@ -44,7 +44,5 @@ interface AdapterInterface
 
     public function paginate($query, int $limit, int $offset);
 
-    public function include($query, array $relationships);
-
-    public function load($model, array $relationships);
+    public function load(array $models, array $relationships);
 }
diff --git a/src/Adapter/EloquentAdapter.php b/src/Adapter/EloquentAdapter.php
index 6a72758..43f4655 100644
--- a/src/Adapter/EloquentAdapter.php
+++ b/src/Adapter/EloquentAdapter.php
@@ -4,9 +4,11 @@ namespace Tobscure\JsonApiServer\Adapter;
 
 use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
 use Tobscure\JsonApiServer\Schema\Attribute;
 use Tobscure\JsonApiServer\Schema\HasMany;
 use Tobscure\JsonApiServer\Schema\HasOne;
+use Tobscure\JsonApiServer\Schema\Relationship;
 
 class EloquentAdapter implements AdapterInterface
 {
@@ -44,6 +46,11 @@ class EloquentAdapter implements AdapterInterface
         return $query->get()->all();
     }
 
+    public function count($query): int
+    {
+        return $query->count();
+    }
+
     public function getId($model): string
     {
         return $model->getKey();
@@ -51,27 +58,48 @@ class EloquentAdapter implements AdapterInterface
 
     public function getAttribute($model, Attribute $field)
     {
-        return $model->{$field->property};
+        return $model->{$this->getAttributeProperty($field)};
+    }
+
+    public function getHasOneId($model, HasOne $field)
+    {
+        $relation = $model->{$this->getRelationshipProperty($field)}();
+
+        if ($relation instanceof BelongsTo) {
+            $related = $relation->getRelated();
+
+            $key = $model->{$relation->getForeignKeyName()};
+
+            if ($key) {
+                return $related->forceFill([$related->getKeyName() => $key]);
+            }
+
+            return null;
+        }
+
+        return $model->{$this->getRelationshipProperty($field)};
     }
 
     public function getHasOne($model, HasOne $field)
     {
-        return $model->{$field->property};
+        return $model->{$this->getRelationshipProperty($field)};
     }
 
     public function getHasMany($model, HasMany $field): array
     {
-        return $model->{$field->property}->all();
+        $collection = $model->{$this->getRelationshipProperty($field)};
+
+        return $collection ? $collection->all() : [];
     }
 
     public function applyAttribute($model, Attribute $field, $value)
     {
-        $model->{$field->property} = $value;
+        $model->{$this->getAttributeProperty($field)} = $value;
     }
 
     public function applyHasOne($model, HasOne $field, $related)
     {
-        $model->{$field->property}()->associate($related);
+        $model->{$this->getRelationshipProperty($field)}()->associate($related);
     }
 
     public function save($model)
@@ -81,7 +109,7 @@ class EloquentAdapter implements AdapterInterface
 
     public function saveHasMany($model, HasMany $field, array $related)
     {
-        $model->{$field->property}()->sync(Collection::make($related));
+        $model->{$this->getRelationshipProperty($field)}()->sync(Collection::make($related));
     }
 
     public function delete($model)
@@ -91,12 +119,12 @@ class EloquentAdapter implements AdapterInterface
 
     public function filterByAttribute($query, Attribute $field, $value)
     {
-        $query->where($field->property, $value);
+        $query->where($this->getAttributeProperty($field), $value);
     }
 
     public function filterByHasOne($query, HasOne $field, array $ids)
     {
-        $property = $field->property;
+        $property = $this->getRelationshipProperty($field);
         $foreignKey = $query->getModel()->{$property}()->getQualifiedForeignKey();
 
         $query->whereIn($foreignKey, $ids);
@@ -104,7 +132,7 @@ class EloquentAdapter implements AdapterInterface
 
     public function filterByHasMany($query, HasMany $field, array $ids)
     {
-        $property = $field->property;
+        $property = $this->getRelationshipProperty($field);
         $relation = $query->getModel()->{$property}();
         $relatedKey = $relation->getRelated()->getQualifiedKeyName();
 
@@ -115,7 +143,7 @@ class EloquentAdapter implements AdapterInterface
 
     public function sortByAttribute($query, Attribute $field, string $direction)
     {
-        $query->orderBy($field->property, $direction);
+        $query->orderBy($this->getAttributeProperty($field), $direction);
     }
 
     public function paginate($query, int $limit, int $offset)
@@ -123,20 +151,48 @@ class EloquentAdapter implements AdapterInterface
         $query->take($limit)->skip($offset);
     }
 
-    public function include($query, array $trail)
+    public function load(array $models, array $trail)
     {
-        $query->with($this->relationshipTrailToPath($trail));
+        (new Collection($models))->load($this->relationshipTrailToPath($trail));
     }
 
-    public function load($model, array $trail)
+    public function loadIds(array $models, Relationship $relationship)
     {
-        $model->load($this->relationshipTrailToPath($trail));
+        if (empty($models)) {
+            return;
+        }
+
+        $property = $this->getRelationshipProperty($relationship);
+        $relation = $models[0]->$property();
+
+        if ($relation instanceof BelongsTo) {
+            return;
+        }
+
+        (new Collection($models))->load([
+            $property => function ($query) use ($relation) {
+                $query->select([
+                    $relation->getRelated()->getKeyName(),
+                    $relation->getForeignKeyName()
+                ]);
+            }
+        ]);
+    }
+
+    private function getAttributeProperty(Attribute $field)
+    {
+        return $field->property ?: strtolower(preg_replace('/(?<!^)[A-Z]/', '_$0', $field->name));
+    }
+
+    private function getRelationshipProperty(Relationship $field)
+    {
+        return $field->property ?: $field->name;
     }
 
     private function relationshipTrailToPath(array $trail)
     {
         return implode('.', array_map(function ($relationship) {
-            return $relationship->property;
+            return $this->getRelationshipProperty($relationship);
         }, $trail));
     }
 }
diff --git a/src/Api.php b/src/Api.php
index b0801b2..176b1f5 100644
--- a/src/Api.php
+++ b/src/Api.php
@@ -7,7 +7,9 @@ use JsonApiPhp\JsonApi;
 use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
 use Psr\Http\Server\RequestHandlerInterface;
+use Tobscure\JsonApiServer\Exception\BadRequestException;
 use Tobscure\JsonApiServer\Exception\MethodNotAllowedException;
+use Tobscure\JsonApiServer\Exception\NotImplementedException;
 use Tobscure\JsonApiServer\Exception\ResourceNotFoundException;
 use Tobscure\JsonApiServer\Handler\Concerns\FindsResources;
 
@@ -51,10 +53,10 @@ class Api implements RequestHandlerInterface
         if ($count === 1) {
             switch ($request->getMethod()) {
                 case 'GET':
-                    return (new Handler\Index($this, $resource))->handle($request);
+                    return $this->handleWithHandler($request, new Handler\Index($this, $resource));
 
                 case 'POST':
-                    return (new Handler\Create($this, $resource))->handle($request);
+                    return $this->handleWithHandler($request, new Handler\Create($this, $resource));
 
                 default:
                     throw new MethodNotAllowedException;
@@ -66,28 +68,32 @@ class Api implements RequestHandlerInterface
         if ($count === 2) {
             switch ($request->getMethod()) {
                 case 'PATCH':
-                    return (new Handler\Update($this, $resource, $model))->handle($request);
+                    return $this->handleWithHandler($request, new Handler\Update($this, $resource, $model));
 
                 case 'GET':
-                    return (new Handler\Show($this, $resource, $model))->handle($request);
+                    return $this->handleWithHandler($request, new Handler\Show($this, $resource, $model));
 
                 case 'DELETE':
-                    return (new Handler\Delete($resource, $model))->handle($request);
+                    return $this->handleWithHandler($request, new Handler\Delete($resource, $model));
 
                 default:
                     throw new MethodNotAllowedException;
             }
         }
 
-        // if ($count === 3) {
-        //     return $this->handleRelated($request, $resource, $model, $segments[2]);
-        // }
+        if ($count === 3) {
+            throw new NotImplementedException;
 
-        // if ($count === 4 && $segments[2] === 'relationship') {
-        //     return $this->handleRelationship($request, $resource, $model, $segments[3]);
-        // }
+            // return $this->handleRelated($request, $resource, $model, $segments[2]);
+        }
 
-        throw new \RuntimeException;
+        if ($count === 4 && $segments[2] === 'relationships') {
+            throw new NotImplementedException;
+
+            // return $this->handleRelationship($request, $resource, $model, $segments[3]);
+        }
+
+        throw new BadRequestException;
     }
 
     private function stripBasePath(string $path): string
@@ -103,13 +109,23 @@ class Api implements RequestHandlerInterface
         return $path;
     }
 
-    public function error(\Throwable $e)
+    private function handleWithHandler(Request $request, RequestHandlerInterface $handler)
     {
+        $request = $request->withAttribute('jsonApiHandler', $handler);
+
+        return $handler->handle($request);
+    }
+
+    public function handleError($e)
+    {
+        if (! $e instanceof ErrorProviderInterface) {
+            $e = new Exception\InternalServerErrorException;
+        }
+
+        $errors = $e->getJsonApiErrors();
+
         $data = new JsonApi\ErrorDocument(
-            new JsonApi\Error(
-                new JsonApi\Error\Title($e->getMessage()),
-                new JsonApi\Error\Detail((string) $e)
-            )
+            ...$errors
         );
 
         return new JsonApiResponse($data);
diff --git a/src/ErrorProviderInterface.php b/src/ErrorProviderInterface.php
new file mode 100644
index 0000000..cd6687d
--- /dev/null
+++ b/src/ErrorProviderInterface.php
@@ -0,0 +1,8 @@
+<?php
+
+namespace Tobscure\JsonApiServer;
+
+interface ErrorProviderInterface
+{
+    public function getJsonApiErrors(): array;
+}
diff --git a/src/Exception/BadRequestException.php b/src/Exception/BadRequestException.php
index 700eed5..81b514a 100644
--- a/src/Exception/BadRequestException.php
+++ b/src/Exception/BadRequestException.php
@@ -2,6 +2,41 @@
 
 namespace Tobscure\JsonApiServer\Exception;
 
-class BadRequestException extends \DomainException
+use JsonApiPhp\JsonApi\Error;
+use Tobscure\JsonApiServer\ErrorProviderInterface;
+
+class BadRequestException extends \DomainException implements ErrorProviderInterface
 {
+    /**
+     * @var string
+     */
+    private $sourceParameter;
+
+    public function __construct(string $message = '', string $sourceParameter = '')
+    {
+        parent::__construct($message);
+
+        $this->sourceParameter = $sourceParameter;
+    }
+
+    public function getJsonApiErrors(): array
+    {
+        $members = [];
+
+        if ($this->message) {
+            $members[] = new Error\Detail($this->message);
+        }
+
+        if ($this->sourceParameter) {
+            $members[] = new Error\SourceParameter($this->sourceParameter);
+        }
+
+        return [
+            new Error(
+                new Error\Title('Bad Request'),
+                new Error\Status('400'),
+                ...$members
+            )
+        ];
+    }
 }
diff --git a/src/Exception/ForbiddenException.php b/src/Exception/ForbiddenException.php
index 7acba10..bfa8702 100644
--- a/src/Exception/ForbiddenException.php
+++ b/src/Exception/ForbiddenException.php
@@ -2,6 +2,18 @@
 
 namespace Tobscure\JsonApiServer\Exception;
 
-class ForbiddenException extends \DomainException
+use JsonApiPhp\JsonApi\Error;
+use Tobscure\JsonApiServer\ErrorProviderInterface;
+
+class BadRequestException extends \DomainException implements ErrorProviderInterface
 {
+    public function getJsonApiErrors(): array
+    {
+        return [
+            new Error(
+                new Error\Title('Forbidden'),
+                new Error\Status('403')
+            )
+        ];
+    }
 }
diff --git a/src/Exception/InternalServerErrorException.php b/src/Exception/InternalServerErrorException.php
new file mode 100644
index 0000000..32fd795
--- /dev/null
+++ b/src/Exception/InternalServerErrorException.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace Tobscure\JsonApiServer\Exception;
+
+use JsonApiPhp\JsonApi\Error;
+use Tobscure\JsonApiServer\ErrorProviderInterface;
+
+class InternalServerErrorException extends \RuntimeException implements ErrorProviderInterface
+{
+    public function getJsonApiErrors(): array
+    {
+        return [
+            new Error(
+                new Error\Title('Internal Server Error'),
+                new Error\Status('500')
+            )
+        ];
+    }
+}
diff --git a/src/Exception/MethodNotAllowedException.php b/src/Exception/MethodNotAllowedException.php
index 7d45260..3406cfd 100644
--- a/src/Exception/MethodNotAllowedException.php
+++ b/src/Exception/MethodNotAllowedException.php
@@ -2,12 +2,18 @@
 
 namespace Tobscure\JsonApiServer\Exception;
 
-use Exception;
+use JsonApiPhp\JsonApi\Error;
+use Tobscure\JsonApiServer\ErrorProviderInterface;
 
-class MethodNotAllowedException extends \DomainException
+class BadRequestException extends \DomainException implements ErrorProviderInterface
 {
-    public function __construct($message = null, $code = 405, Exception $previous = null)
+    public function getJsonApiErrors(): array
     {
-        parent::__construct($message, $code, $previous);
+        return [
+            new Error(
+                new Error\Title('Method Not Allowed'),
+                new Error\Status('405')
+            )
+        ];
     }
 }
diff --git a/src/Exception/NotImplementedException.php b/src/Exception/NotImplementedException.php
new file mode 100644
index 0000000..c2341a6
--- /dev/null
+++ b/src/Exception/NotImplementedException.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace Tobscure\JsonApiServer\Exception;
+
+use JsonApiPhp\JsonApi\Error;
+use Tobscure\JsonApiServer\ErrorProviderInterface;
+
+class NotImplementedException extends \DomainException implements ErrorProviderInterface
+{
+    public function getJsonApiErrors(): array
+    {
+        return [
+            new Error(
+                new Error\Title('Not Implemented'),
+                new Error\Status('501')
+            )
+        ];
+    }
+}
diff --git a/src/Exception/ResourceNotFoundException.php b/src/Exception/ResourceNotFoundException.php
index 642381b..bea9972 100644
--- a/src/Exception/ResourceNotFoundException.php
+++ b/src/Exception/ResourceNotFoundException.php
@@ -2,21 +2,42 @@
 
 namespace Tobscure\JsonApiServer\Exception;
 
-use RuntimeException;
+use JsonApiPhp\JsonApi\Error;
+use Tobscure\JsonApiServer\ErrorProviderInterface;
 
-class ResourceNotFoundException extends RuntimeException
+class ResourceNotFoundException extends \RuntimeException implements ErrorProviderInterface
 {
     protected $type;
+    protected $id;
 
-    public function __construct(string $type, $id = null)
+    public function __construct(string $type, string $id = null)
     {
-        parent::__construct("Resource [$type".($id !== null ? ".$id" : '').'] not found.');
+        parent::__construct(
+            sprintf('Resource [%s] not found.', $type.($id !== null ? '.'.$id : ''))
+        );
 
         $this->type = $type;
+        $this->id = $id;
     }
 
-    public function getStatusCode()
+    public function getJsonApiErrors(): array
     {
-        return 404;
+        return [
+            new Error(
+                new Error\Title('Resource Not Found'),
+                new Error\Status('404'),
+                new Error\Detail($this->getMessage())
+            )
+        ];
+    }
+
+    public function getType(): string
+    {
+        return $this->type;
+    }
+
+    public function getId(): ?string
+    {
+        return $this->id;
     }
 }
diff --git a/src/Exception/UnprocessableEntityException.php b/src/Exception/UnprocessableEntityException.php
index 210d1d9..5df10e2 100644
--- a/src/Exception/UnprocessableEntityException.php
+++ b/src/Exception/UnprocessableEntityException.php
@@ -2,8 +2,18 @@
 
 namespace Tobscure\JsonApiServer\Exception;
 
-use Exception;
+use JsonApiPhp\JsonApi\Error;
+use Tobscure\JsonApiServer\ErrorProviderInterface;
 
-class UnprocessableEntityException extends \DomainException
+class UnprocessableEntityException extends \DomainException implements ErrorProviderInterface
 {
+    public function getJsonApiErrors(): array
+    {
+        return [
+            new Error(
+                new Error\Title('Unprocessable Entity'),
+                new Error\Status('422')
+            )
+        ];
+    }
 }
diff --git a/src/Handler/Concerns/FindsResources.php b/src/Handler/Concerns/FindsResources.php
index c34db93..e6e2285 100644
--- a/src/Handler/Concerns/FindsResources.php
+++ b/src/Handler/Concerns/FindsResources.php
@@ -15,7 +15,11 @@ trait FindsResources
         $query = $adapter->query();
 
         foreach ($resource->getSchema()->scopes as $scope) {
-            $scope($query, $request);
+            $scope($request, $query);
+        }
+
+        foreach ($resource->getSchema()->singleScopes as $scope) {
+            $scope($request, $query, $id);
         }
 
         $model = $adapter->find($query, $id);
diff --git a/src/Handler/Concerns/IncludesData.php b/src/Handler/Concerns/IncludesData.php
index a563286..ef20730 100644
--- a/src/Handler/Concerns/IncludesData.php
+++ b/src/Handler/Concerns/IncludesData.php
@@ -22,7 +22,7 @@ trait IncludesData
             return $include;
         }
 
-        return $this->defaultInclude($this->resource);
+        return [];
     }
 
     private function parseInclude(string $include): array
@@ -54,7 +54,7 @@ trait IncludesData
                 || ! $schema->fields[$name] instanceof Relationship
                 || ($schema->fields[$name] instanceof HasMany && ! $schema->fields[$name]->includable)
             ) {
-                throw new BadRequestException("Invalid include [{$path}{$name}]");
+                throw new BadRequestException("Invalid include [{$path}{$name}]", 'include');
             }
 
             $relatedResource = $this->api->getResource($schema->fields[$name]->resource);
@@ -63,23 +63,6 @@ trait IncludesData
         }
     }
 
-    private function defaultInclude(ResourceType $resource): array
-    {
-        $include = [];
-
-        foreach ($resource->getSchema()->fields as $name => $field) {
-            if (! $field instanceof Relationship || ! $field->included) {
-                continue;
-            }
-
-            $include[$name] = $this->defaultInclude(
-                $this->api->getResource($field->resource)
-            );
-        }
-
-        return $include;
-    }
-
     private function buildRelationshipTrails(ResourceType $resource, array $include): array
     {
         $schema = $resource->getSchema();
@@ -88,7 +71,9 @@ trait IncludesData
         foreach ($include as $name => $nested) {
             $relationship = $schema->fields[$name];
 
-            $trails[] = [$relationship];
+            if ($relationship->loadable) {
+                $trails[] = [$relationship];
+            }
 
             $relatedResource = $this->api->getResource($relationship->resource);
 
@@ -105,4 +90,24 @@ trait IncludesData
 
         return $trails;
     }
+
+    private function loadRelationships(array $models, array $include, Request $request)
+    {
+        $adapter = $this->resource->getAdapter();
+        $schema = $this->resource->getSchema();
+
+        foreach ($schema->fields as $name => $field) {
+            if (! $field instanceof Relationship || ! ($field->linkage)($request) || ! $field->loadable) {
+                continue;
+            }
+
+            $adapter->loadIds($models, $field);
+        }
+
+        $trails = $this->buildRelationshipTrails($this->resource, $include);
+
+        foreach ($trails as $relationships) {
+            $adapter->load($models, $relationships);
+        }
+    }
 }
diff --git a/src/Handler/Concerns/SavesData.php b/src/Handler/Concerns/SavesData.php
index 4e3299f..feb040c 100644
--- a/src/Handler/Concerns/SavesData.php
+++ b/src/Handler/Concerns/SavesData.php
@@ -35,6 +35,8 @@ trait SavesData
         $adapter->save($model);
 
         $this->saveFields($data, $model, $request);
+
+        $this->runSavedCallbacks($data, $model, $request);
     }
 
     private function parseData($body): array
@@ -65,8 +67,12 @@ trait SavesData
 
     private function getModelForIdentifier(Request $request, $identifier)
     {
-        if (! isset($identifier['type']) || ! isset($identifier['id'])) {
-            throw new BadRequestException('type/id not specified');
+        if (! isset($identifier['type'])) {
+            throw new BadRequestException('type not specified');
+        }
+
+        if (! isset($identifier['id'])) {
+            throw new BadRequestException('id not specified');
         }
 
         $resource = $this->api->getResource($identifier['type']);
@@ -96,7 +102,7 @@ trait SavesData
         foreach ($schema->fields as $name => $field) {
             $valueProvided = isset($data[$field->location][$name]);
 
-            if ($valueProvided && ! ($field->isWritable)($model, $request)) {
+            if ($valueProvided && ! ($field->isWritable)($request, $model)) {
                 throw new BadRequestException("Field [$name] is not writable");
             }
         }
@@ -152,7 +158,7 @@ trait SavesData
             };
 
             foreach ($field->validators as $validator) {
-                $validator($fail, $data[$field->location][$name], $model, $request);
+                $validator($fail, $data[$field->location][$name] ?? null, $request, $model, $field);
             }
         }
 
@@ -202,10 +208,25 @@ trait SavesData
             $value = $data[$field->location][$name];
 
             if ($field->saver) {
-                ($field->saver)($model, $value, $request);
+                ($field->saver)($request, $model, $value);
             } elseif ($field instanceof Schema\HasMany) {
                 $adapter->saveHasMany($model, $field, $value);
             }
         }
     }
+
+    private function runSavedCallbacks(array $data, $model, Request $request)
+    {
+        $schema = $this->resource->getSchema();
+
+        foreach ($schema->fields as $name => $field) {
+            if (! isset($data[$field->location][$name])) {
+                continue;
+            }
+
+            foreach ($field->savedCallbacks as $callback) {
+                $callback($request, $model, $data[$field->location][$name]);
+            }
+        }
+    }
 }
diff --git a/src/Handler/Create.php b/src/Handler/Create.php
index 4b33d3a..a231cf3 100644
--- a/src/Handler/Create.php
+++ b/src/Handler/Create.php
@@ -24,14 +24,24 @@ class Create implements RequestHandlerInterface
 
     public function handle(Request $request): Response
     {
-        if (! ($this->resource->getSchema()->isCreatable)($request)) {
+        $schema = $this->resource->getSchema();
+
+        if (! ($schema->isCreatable)($request)) {
             throw new ForbiddenException('You cannot create this resource');
         }
 
         $model = $this->resource->getAdapter()->create();
 
+        foreach ($schema->creatingCallbacks as $callback) {
+            $callback($request, $model);
+        }
+
         $this->save($model, $request, true);
 
+        foreach ($schema->createdCallbacks as $callback) {
+            $callback($request, $model);
+        }
+
         return (new Show($this->api, $this->resource, $model))
             ->handle($request)
             ->withStatus(201);
diff --git a/src/Handler/Delete.php b/src/Handler/Delete.php
index 92f52a9..cc641f1 100644
--- a/src/Handler/Delete.php
+++ b/src/Handler/Delete.php
@@ -22,12 +22,22 @@ class Delete implements RequestHandlerInterface
 
     public function handle(Request $request): Response
     {
-        if (! ($this->resource->getSchema()->isDeletable)($this->model, $request)) {
+        $schema = $this->resource->getSchema();
+
+        if (! ($schema->isDeletable)($request, $this->model)) {
             throw new ForbiddenException('You cannot delete this resource');
         }
 
+        foreach ($schema->deletingCallbacks as $callback) {
+            $callback($request, $this->model);
+        }
+
         $this->resource->getAdapter()->delete($this->model);
 
+        foreach ($schema->deletedCallbacks as $callback) {
+            $callback($request, $this->model);
+        }
+
         return new EmptyResponse;
     }
 }
diff --git a/src/Handler/Index.php b/src/Handler/Index.php
index 0908757..e2b2eea 100644
--- a/src/Handler/Index.php
+++ b/src/Handler/Index.php
@@ -3,6 +3,8 @@
 namespace Tobscure\JsonApiServer\Handler;
 
 use JsonApiPhp\JsonApi;
+use JsonApiPhp\JsonApi\Link;
+use JsonApiPhp\JsonApi\Meta;
 use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
 use Psr\Http\Server\RequestHandlerInterface;
@@ -30,7 +32,71 @@ class Index implements RequestHandlerInterface
     {
         $include = $this->getInclude($request);
 
-        $models = $this->getModels($include, $request);
+        $request = $this->extractQueryParams($request);
+
+        $adapter = $this->resource->getAdapter();
+        $schema = $this->resource->getSchema();
+
+        $query = $adapter->query();
+
+        foreach ($schema->scopes as $scope) {
+            $scope($request, $query);
+        }
+
+        foreach ($schema->indexScopes as $scope) {
+            $scope($request, $query);
+        }
+
+        if ($filter = $request->getAttribute('jsonApiFilter')) {
+            $this->filter($query, $filter, $request);
+        }
+
+        $offset = $request->getAttribute('jsonApiOffset');
+        $limit = $request->getAttribute('jsonApiLimit');
+        $total = null;
+
+        $paginationLinks = [];
+        $members = [
+            new Link\SelfLink($this->buildUrl($request))
+        ];
+
+        if ($offset > 0) {
+            $paginationLinks[] = new Link\FirstLink($this->buildUrl($request, ['page' => ['offset' => 0]]));
+
+            $prevOffset = $offset - $limit;
+
+            if ($prevOffset < 0) {
+                $params = ['page' => ['offset' => 0, 'limit' => $offset]];
+            } else {
+                $params = ['page' => ['offset' => max(0, $prevOffset)]];
+            }
+
+            $paginationLinks[] = new Link\PrevLink($this->buildUrl($request, $params));
+        }
+
+        if ($schema->countable) {
+            $total = $adapter->count($query);
+
+            $members[] = new Meta('total', $total);
+
+            if ($offset + $limit < $total) {
+                $paginationLinks[] = new Link\LastLink($this->buildUrl($request, ['page' => ['offset' => floor(($total - 1) / $limit) * $limit]]));
+            }
+        }
+
+        if ($sort = $request->getAttribute('jsonApiSort')) {
+            $this->sort($query, $sort, $request);
+        }
+
+        $this->paginate($query, $request);
+
+        $models = $adapter->get($query);
+
+        if ((count($models) && $total === null) || $offset + $limit < $total) {
+            $paginationLinks[] = new Link\NextLink($this->buildUrl($request, ['page' => ['offset' => $offset + $limit]]));
+        }
+
+        $this->loadRelationships($models, $include, $request);
 
         $serializer = new Serializer($this->api, $request);
 
@@ -40,52 +106,108 @@ class Index implements RequestHandlerInterface
 
         return new JsonApiResponse(
             new JsonApi\CompoundDocument(
-                new JsonApi\ResourceCollection(...$serializer->primary()),
-                new JsonApi\Included(...$serializer->included())
+                new JsonApi\PaginatedCollection(
+                    new JsonApi\Pagination(...$paginationLinks),
+                    new JsonApi\ResourceCollection(...$serializer->primary())
+                ),
+                new JsonApi\Included(...$serializer->included()),
+                ...$members
             )
         );
     }
 
-    private function getModels(array $include, Request $request)
+    private function buildUrl(Request $request, array $overrideParams = []): string
     {
-        $adapter = $this->resource->getAdapter();
+        [$selfUrl] = explode('?', $request->getUri(), 2);
+        $queryParams = $request->getQueryParams();
 
-        $query = $adapter->query();
+        $queryParams = array_replace_recursive($queryParams, $overrideParams);
 
-        foreach ($this->resource->getSchema()->scopes as $scope) {
-            $scope($query, $request);
+        if (isset($queryParams['page']['offset']) && $queryParams['page']['offset'] <= 0) {
+            unset($queryParams['page']['offset']);
         }
 
+        $queryString = http_build_query($queryParams);
+
+        return $selfUrl.($queryString ? '?'.$queryString : '');
+    }
+
+    private function extractQueryParams(Request $request): Request
+    {
+        $schema = $this->resource->getSchema();
+
         $queryParams = $request->getQueryParams();
 
-        if (isset($queryParams['sort'])) {
-            $this->sort($query, $queryParams['sort'], $request);
+        $limit = $this->resource->getSchema()->paginate;
+
+        if (isset($queryParams['page']['limit'])) {
+            $limit = $queryParams['page']['limit'];
+
+            if ((! is_int($limit) && ! ctype_digit($limit)) || $limit < 1) {
+                throw new BadRequestException('page[limit] must be a positive integer', 'page[limit]');
+            }
+
+            $limit = min($this->resource->getSchema()->limit, $limit);
         }
 
-        if (isset($queryParams['filter'])) {
-            $this->filter($query, $queryParams['filter'], $request);
+        $offset = 0;
+
+        if (isset($queryParams['page']['offset'])) {
+            $offset = $queryParams['page']['offset'];
+
+            if ((! is_int($offset) && ! ctype_digit($offset)) || $offset < 0) {
+                throw new BadRequestException('page[offset] must be a non-negative integer', 'page[offset]');
+            }
         }
 
-        $this->paginate($query, $request);
+        $request = $request
+            ->withAttribute('jsonApiLimit', $limit)
+            ->withAttribute('jsonApiOffset', $offset);
 
-        $this->include($query, $include);
+        $sort = $queryParams['sort'] ?? $this->resource->getSchema()->defaultSort;
 
-        return $adapter->get($query);
+        if ($sort) {
+            $sort = $this->parseSort($sort);
+
+            foreach ($sort as $name => $direction) {
+                if (! isset($schema->fields[$name])
+                    || ! $schema->fields[$name] instanceof Schema\Attribute
+                    || ! $schema->fields[$name]->sortable
+                ) {
+                    throw new BadRequestException("Invalid sort field [$name]", 'sort');
+                }
+            }
+        }
+
+        $request = $request->withAttribute('jsonApiSort', $sort);
+
+        $filter = $queryParams['filter'] ?? null;
+
+        if ($filter) {
+            if (! is_array($filter)) {
+                throw new BadRequestException('filter must be an array', 'filter');
+            }
+
+            foreach ($filter as $name => $value) {
+                if (! isset($schema->fields[$name])
+                    || ! $schema->fields[$name]->filterable
+                ) {
+                    throw new BadRequestException("Invalid filter [$name]", "filter[$name]");
+                }
+            }
+        }
+
+        $request = $request->withAttribute('jsonApiFilter', $filter);
+
+        return $request;
     }
 
-    private function sort($query, string $sort, Request $request)
+    private function sort($query, array $sort, Request $request)
     {
         $schema = $this->resource->getSchema();
         $adapter = $this->resource->getAdapter();
 
-        foreach ($this->parseSort($sort) as $name => $direction) {
-            if (! isset($schema->fields[$name])
-                || ! $schema->fields[$name] instanceof Schema\Attribute
-                || ! $schema->fields[$name]->sortable
-            ) {
-                throw new BadRequestException("Invalid sort field [$name]");
-            }
-
+        foreach ($sort as $name => $direction) {
             $attribute = $schema->fields[$name];
 
             if ($attribute->sorter) {
@@ -117,19 +239,10 @@ class Index implements RequestHandlerInterface
 
     private function paginate($query, Request $request)
     {
-        $queryParams = $request->getQueryParams();
+        $limit = $request->getAttribute('jsonApiLimit');
+        $offset = $request->getAttribute('jsonApiOffset');
 
-        $maxLimit = $this->resource->getSchema()->paginate;
-
-        $limit = isset($queryParams['page']['limit']) ? min($maxLimit, (int) $queryParams['page']['limit']) : $maxLimit;
-
-        $offset = isset($queryParams['page']['offset']) ? (int) $queryParams['page']['offset'] : 0;
-
-        if ($offset < 0) {
-            throw new BadRequestException('page[offset] must be >=0');
-        }
-
-        if ($limit) {
+        if ($limit || $offset) {
             $this->resource->getAdapter()->paginate($query, $limit, $offset);
         }
     }
@@ -139,17 +252,7 @@ class Index implements RequestHandlerInterface
         $schema = $this->resource->getSchema();
         $adapter = $this->resource->getAdapter();
 
-        if (! is_array($filter)) {
-            throw new BadRequestException('filter must be an array');
-        }
-
         foreach ($filter as $name => $value) {
-            if (! isset($schema->fields[$name])
-                || ! $schema->fields[$name]->filterable
-            ) {
-                throw new BadRequestException("Invalid filter [$name]");
-            }
-
             $field = $schema->fields[$name];
 
             if ($field->filter) {
@@ -165,15 +268,4 @@ class Index implements RequestHandlerInterface
             }
         }
     }
-
-    private function include($query, array $include)
-    {
-        $adapter = $this->resource->getAdapter();
-
-        $trails = $this->buildRelationshipTrails($this->resource, $include);
-
-        foreach ($trails as $relationships) {
-            $adapter->include($query, $relationships);
-        }
-    }
 }
diff --git a/src/Handler/Show.php b/src/Handler/Show.php
index d8c110c..ebab0dd 100644
--- a/src/Handler/Show.php
+++ b/src/Handler/Show.php
@@ -30,7 +30,7 @@ class Show implements RequestHandlerInterface
     {
         $include = $this->getInclude($request);
 
-        $this->load($include);
+        $this->loadRelationships([$this->model], $include, $request);
 
         $serializer = new Serializer($this->api, $request);
 
@@ -43,15 +43,4 @@ class Show implements RequestHandlerInterface
             )
         );
     }
-
-    private function load(array $include)
-    {
-        $adapter = $this->resource->getAdapter();
-
-        $trails = $this->buildRelationshipTrails($this->resource, $include);
-
-        foreach ($trails as $relationships) {
-            $adapter->load($this->model, $relationships);
-        }
-    }
 }
diff --git a/src/Handler/Update.php b/src/Handler/Update.php
index af238a7..d3f75ad 100644
--- a/src/Handler/Update.php
+++ b/src/Handler/Update.php
@@ -6,6 +6,7 @@ use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
 use Psr\Http\Server\RequestHandlerInterface;
 use Tobscure\JsonApiServer\Api;
+use Tobscure\JsonApiServer\Exception\ForbiddenException;
 use Tobscure\JsonApiServer\ResourceType;
 
 class Update implements RequestHandlerInterface
@@ -25,10 +26,22 @@ class Update implements RequestHandlerInterface
 
     public function handle(Request $request): Response
     {
-        $adapter = $this->resource->getAdapter();
+        $schema = $this->resource->getSchema();
+
+        if (! ($schema->isUpdatable)($request, $this->model)) {
+            throw new ForbiddenException('You cannot update this resource');
+        }
+
+        foreach ($schema->updatingCallbacks as $callback) {
+            $callback($request, $this->model);
+        }
 
         $this->save($this->model, $request);
 
+        foreach ($schema->updatedCallbacks as $callback) {
+            $callback($request, $this->model);
+        }
+
         return (new Show($this->api, $this->resource, $this->model))->handle($request);
     }
 }
diff --git a/src/Schema/Attribute.php b/src/Schema/Attribute.php
index 847f348..2ce76f2 100644
--- a/src/Schema/Attribute.php
+++ b/src/Schema/Attribute.php
@@ -13,11 +13,6 @@ class Attribute extends Field
     public $sortable = false;
     public $sorter;
 
-    public function __construct(string $name)
-    {
-        parent::__construct($name);
-    }
-
     public function sortable(Closure $callback = null)
     {
         $this->sortable = true;
diff --git a/src/Schema/Builder.php b/src/Schema/Builder.php
index dda30dd..6bf6b96 100644
--- a/src/Schema/Builder.php
+++ b/src/Schema/Builder.php
@@ -7,11 +7,24 @@ use Closure;
 class Builder
 {
     public $fields = [];
+    public $meta = [];
     public $paginate = 20;
+    public $limit = 50;
+    public $countable = true;
     public $scopes = [];
+    public $indexScopes = [];
+    public $singleScopes = [];
     public $isVisible;
     public $isCreatable;
+    public $creatingCallbacks = [];
+    public $createdCallbacks = [];
+    public $isUpdatable;
+    public $updatingCallbacks = [];
+    public $updatedCallbacks = [];
     public $isDeletable;
+    public $deletingCallbacks = [];
+    public $deletedCallbacks = [];
+    public $defaultSort;
 
     public function __construct()
     {
@@ -46,16 +59,46 @@ class Builder
         return $field;
     }
 
+    public function meta(string $name, $value)
+    {
+        return $this->meta[$name] = new Meta($name, $value);
+    }
+
     public function paginate(?int $perPage)
     {
         $this->paginate = $perPage;
     }
 
+    public function limit(?int $limit)
+    {
+        $this->limit = $limit;
+    }
+
+    public function countable()
+    {
+        $this->countable = true;
+    }
+
+    public function uncountable()
+    {
+        $this->countable = false;
+    }
+
     public function scope(Closure $callback)
     {
         $this->scopes[] = $callback;
     }
 
+    public function scopeIndex(Closure $callback)
+    {
+        $this->indexScopes[] = $callback;
+    }
+
+    public function scopeSingle(Closure $callback)
+    {
+        $this->singleScopes[] = $callback;
+    }
+
     public function creatableIf(Closure $condition)
     {
         $this->isCreatable = $condition;
@@ -84,6 +127,54 @@ class Builder
         });
     }
 
+    public function creating(Closure $callback)
+    {
+        $this->creatingCallbacks[] = $callback;
+    }
+
+    public function created(Closure $callback)
+    {
+        $this->createdCallbacks[] = $callback;
+    }
+
+    public function updatableIf(Closure $condition)
+    {
+        $this->isUpdatable = $condition;
+
+        return $this;
+    }
+
+    public function updatable()
+    {
+        return $this->updatableIf(function () {
+            return true;
+        });
+    }
+
+    public function notUpdatableIf(Closure $condition)
+    {
+        return $this->updatableIf(function (...$args) use ($condition) {
+            return ! $condition(...$args);
+        });
+    }
+
+    public function notUpdatable()
+    {
+        return $this->notUpdatableIf(function () {
+            return true;
+        });
+    }
+
+    public function updating(Closure $callback)
+    {
+        $this->updatingCallbacks[] = $callback;
+    }
+
+    public function updated(Closure $callback)
+    {
+        $this->updatedCallbacks[] = $callback;
+    }
+
     public function deletableIf(Closure $condition)
     {
         $this->isDeletable = $condition;
@@ -112,6 +203,21 @@ class Builder
         });
     }
 
+    public function deleting(Closure $callback)
+    {
+        $this->deletingCallbacks[] = $callback;
+    }
+
+    public function deleted(Closure $callback)
+    {
+        $this->deletedCallbacks[] = $callback;
+    }
+
+    public function defaultSort(string $sort)
+    {
+        $this->defaultSort = $sort;
+    }
+
     private function field(string $class, string $name, string $property = null)
     {
         if (! isset($this->fields[$name]) || ! $this->fields[$name] instanceof $class) {
diff --git a/src/Schema/Field.php b/src/Schema/Field.php
index f58f1a8..2c9220e 100644
--- a/src/Schema/Field.php
+++ b/src/Schema/Field.php
@@ -13,6 +13,7 @@ abstract class Field
     public $getter;
     public $setter;
     public $saver;
+    public $savedCallbacks = [];
     public $default;
     public $validators = [];
     public $filterable = false;
@@ -20,7 +21,7 @@ abstract class Field
 
     public function __construct(string $name)
     {
-        $this->name = $this->property = $name;
+        $this->name = $name;
 
         $this->visible();
         $this->readonly();
@@ -110,6 +111,13 @@ abstract class Field
         return $this;
     }
 
+    public function saved(Closure $callback)
+    {
+        $this->savedCallbacks[] = $callback;
+
+        return $this;
+    }
+
     public function default($value)
     {
         $this->default = $this->wrap($value);
@@ -132,7 +140,7 @@ abstract class Field
         return $this;
     }
 
-    private function wrap($value)
+    protected function wrap($value)
     {
         if (! $value instanceof Closure) {
             $value = function () use ($value) {
diff --git a/src/Schema/Meta.php b/src/Schema/Meta.php
new file mode 100644
index 0000000..6759552
--- /dev/null
+++ b/src/Schema/Meta.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace Tobscure\JsonApiServer\Schema;
+
+use Closure;
+
+class Meta
+{
+    public $name;
+    public $value;
+
+    public function __construct(string $name, $value)
+    {
+        $this->name = $name;
+        $this->value = $this->wrap($value);
+    }
+
+    private function wrap($value)
+    {
+        if (! $value instanceof Closure) {
+            $value = function () use ($value) {
+                return $value;
+            };
+        }
+
+        return $value;
+    }
+}
diff --git a/src/Schema/Relationship.php b/src/Schema/Relationship.php
index 561260f..e842865 100644
--- a/src/Schema/Relationship.php
+++ b/src/Schema/Relationship.php
@@ -4,15 +4,26 @@ namespace Tobscure\JsonApiServer\Schema;
 
 use Closure;
 use Spatie\Macroable\Macroable;
+use Tobscure\JsonApiServer\Handler\Show;
 
 abstract class Relationship extends Field
 {
     use Macroable;
 
     public $location = 'relationships';
+    public $linkage;
+    public $hasLinks = true;
+    public $loadable = true;
     public $included = false;
     public $resource;
 
+    public function __construct(string $name)
+    {
+        parent::__construct($name);
+
+        $this->noLinkage();
+    }
+
     public function resource($resource)
     {
         $this->resource = $resource;
@@ -20,10 +31,59 @@ abstract class Relationship extends Field
         return $this;
     }
 
+    public function linkageIf(Closure $condition)
+    {
+        $this->linkage = $condition;
+
+        return $this;
+    }
+
+    public function linkage()
+    {
+        return $this->linkageIf(function () {
+            return true;
+        });
+    }
+
+    public function linkageIfSingle()
+    {
+        return $this->linkageIf(function ($request) {
+            return $request->getAttribute('jsonApiHandler') instanceof Show;
+        });
+    }
+
+    public function noLinkage()
+    {
+        return $this->linkageIf(function () {
+            return false;
+        });
+    }
+
+    public function loadable()
+    {
+        $this->loadable = true;
+
+        return $this;
+    }
+
+    public function notLoadable()
+    {
+        $this->loadable = false;
+
+        return $this;
+    }
+
     public function included()
     {
         $this->included = true;
 
         return $this;
     }
+
+    public function noLinks()
+    {
+        $this->hasLinks = false;
+
+        return $this;
+    }
 }
diff --git a/src/Serializer.php b/src/Serializer.php
index 1f9d72c..2177460 100644
--- a/src/Serializer.php
+++ b/src/Serializer.php
@@ -37,38 +37,58 @@ class Serializer
             'type' => $resource->getType(),
             'id' => $adapter->getId($model),
             'fields' => [],
-            'links' => []
+            'links' => [],
+            'meta' => []
         ];
 
+        $resourceUrl = $this->api->getBaseUrl().'/'.$data['type'].'/'.$data['id'];
+
+        ksort($schema->fields);
+
         foreach ($schema->fields as $name => $field) {
-            if (($field instanceof Schema\Relationship && ! isset($include[$name]))
-                || ! ($field->isVisible)($model, $this->request)
-            ) {
+            if (! ($field->isVisible)($this->request, $model)) {
                 continue;
             }
 
-            $value = $this->getValue($field, $adapter, $model);
-
             if ($field instanceof Schema\Attribute) {
-                $value = $this->attribute($field, $value);
-            } elseif ($field instanceof Schema\HasOne) {
-                $value = $this->toOne($field, $value, $include[$name] ?? []);
-            } elseif ($field instanceof Schema\HasMany) {
-                $value = $this->toMany($field, $value, $include[$name] ?? []);
+                $value = $this->attribute($field, $model, $adapter);
+            } elseif ($field instanceof Schema\Relationship) {
+                $isIncluded = isset($include[$name]);
+                $isLinkage = ($field->linkage)($this->request);
+
+                if (! $isIncluded && ! $isLinkage) {
+                    $value = $this->emptyRelationship($field, $resourceUrl);
+                } elseif ($field instanceof Schema\HasOne) {
+                    $value = $this->toOne($field, $model, $adapter, $isIncluded, $isLinkage, $include[$name] ?? [], $resourceUrl);
+                } elseif ($field instanceof Schema\HasMany) {
+                    $value = $this->toMany($field, $model, $adapter, $isIncluded, $isLinkage, $include[$name] ?? [], $resourceUrl);
+                }
             }
 
             $data['fields'][$name] = $value;
         }
 
-        $data['links']['self'] = new JsonApi\Link\SelfLink($this->api->getBaseUrl().'/'.$data['type'].'/'.$data['id']);
+        $data['links']['self'] = new JsonApi\Link\SelfLink($resourceUrl);
+
+        ksort($schema->meta);
+
+        foreach ($schema->meta as $name => $meta) {
+            $data['meta'][$name] = new JsonApi\Meta($meta->name, ($meta->value)($this->request, $model));
+        }
 
         $this->merge($data);
 
         return $data;
     }
 
-    private function attribute(Schema\Attribute $field, $value): JsonApi\Attribute
+    private function attribute(Schema\Attribute $field, $model, AdapterInterface $adapter): JsonApi\Attribute
     {
+        if ($field->getter) {
+            $value = ($field->getter)($this->request, $model);
+        } else {
+            $value = $adapter->getAttribute($model, $field);
+        }
+
         if ($value instanceof DateTimeInterface) {
             $value = $value->format(DateTime::RFC3339);
         }
@@ -76,31 +96,84 @@ class Serializer
         return new JsonApi\Attribute($field->name, $value);
     }
 
-    private function toOne(Schema\Relationship $field, $value, array $include)
+    private function toOne(Schema\HasOne $field, $model, AdapterInterface $adapter, bool $isIncluded, bool $isLinkage, array $include, string $resourceUrl)
     {
-        if (! $value) {
-            return new JsonApi\ToNull($field->name);
+        $links = $this->getRelationshipLinks($field, $resourceUrl);
+
+        if ($field->getter) {
+            $value = ($field->getter)($this->request, $model);
+        } else {
+            $value = $isIncluded ? $adapter->getHasOne($model, $field) : ($isLinkage && $field->loadable ? $adapter->getHasOneId($model, $field) : null);
         }
 
-        $identifier = $this->addRelated($field, $value, $include);
+        if (! $value) {
+            return new JsonApi\ToNull(
+                $field->name,
+                ...$links
+            );
+        }
 
-        return new JsonApi\ToOne($field->name, $identifier);
+        if ($isIncluded) {
+            $identifier = $this->addRelated($field, $value, $include);
+        } else {
+            $identifier = $this->relatedResourceIdentifier($field, $value);
+        }
+
+
+        return new JsonApi\ToOne(
+            $field->name,
+            $identifier,
+            ...$links
+        );
     }
 
-    private function toMany(Schema\Relationship $field, $value, array $include): JsonApi\ToMany
+    private function toMany(Schema\HasMany $field, $model, AdapterInterface $adapter, bool $isIncluded, bool $isLinkage, array $include, string $resourceUrl)
     {
+        if ($field->getter) {
+            $value = ($field->getter)($this->request, $model);
+        } else {
+            $value = $isLinkage ? $adapter->getHasMany($model, $field) : null;
+        }
+
         $identifiers = [];
 
-        foreach ($value as $relatedModel) {
-            $identifiers[] = $this->addRelated($field, $relatedModel, $include);
+        if ($isIncluded) {
+            foreach ($value as $relatedModel) {
+                $identifiers[] = $this->addRelated($field, $relatedModel, $include);
+            }
+        } else {
+            foreach ($value as $relatedModel) {
+                $identifiers[] = $this->relatedResourceIdentifier($field, $relatedModel);
+            }
         }
 
         return new JsonApi\ToMany(
             $field->name,
-            new JsonApi\ResourceIdentifierCollection(...$identifiers)
+            new JsonApi\ResourceIdentifierCollection(...$identifiers),
+            ...$this->getRelationshipLinks($field, $resourceUrl)
         );
     }
 
+    private function emptyRelationship(Schema\Relationship $field, string $resourceUrl): JsonApi\EmptyRelationship
+    {
+        return new JsonApi\EmptyRelationship(
+            $field->name,
+            ...$this->getRelationshipLinks($field, $resourceUrl)
+        );
+    }
+
+    private function getRelationshipLinks(Schema\Relationship $field, string $resourceUrl): array
+    {
+        if (! $field->hasLinks) {
+            return [];
+        }
+
+        return [
+            new JsonApi\Link\SelfLink($resourceUrl.'/relationships/'.$field->name),
+            new JsonApi\Link\RelatedLink($resourceUrl.'/'.$field->name)
+        ];
+    }
+
     private function addRelated(Schema\Relationship $field, $model, array $include): JsonApi\ResourceIdentifier
     {
         $relatedResource = $this->api->getResource($field->resource);
@@ -110,19 +183,6 @@ class Serializer
         );
     }
 
-    private function getValue(Schema\Field $field, AdapterInterface $adapter, $model)
-    {
-        if ($field->getter) {
-            return ($field->getter)($model, $this->request);
-        } elseif ($field instanceof Schema\Attribute) {
-            return $adapter->getAttribute($model, $field);
-        } elseif ($field instanceof Schema\HasOne) {
-            return $adapter->getHasOne($model, $field);
-        } elseif ($field instanceof Schema\HasMany) {
-            return $adapter->getHasMany($model, $field);
-        }
-    }
-
     private function merge($data): void
     {
         $key = $data['type'].':'.$data['id'];
@@ -130,6 +190,7 @@ class Serializer
         if (isset($this->map[$key])) {
             $this->map[$key]['fields'] = array_merge($this->map[$key]['fields'], $data['fields']);
             $this->map[$key]['links'] = array_merge($this->map[$key]['links'], $data['links']);
+            $this->map[$key]['meta'] = array_merge($this->map[$key]['meta'], $data['meta']);
         } else {
             $this->map[$key] = $data;
         }
@@ -162,7 +223,8 @@ class Serializer
             $data['type'],
             $data['id'],
             ...array_values($data['fields']),
-            ...array_values($data['links'])
+            ...array_values($data['links']),
+            ...array_values($data['meta'])
         );
     }
 
@@ -173,4 +235,14 @@ class Serializer
             $data['id']
         );
     }
+
+    private function relatedResourceIdentifier(Schema\Relationship $field, $model)
+    {
+        $relatedResource = $this->api->getResource($field->resource);
+
+        return $this->resourceIdentifier([
+            'type' => $field->resource,
+            'id' => $relatedResource->getAdapter()->getId($model)
+        ]);
+    }
 }
diff --git a/src/StatusProviderInterface.php b/src/StatusProviderInterface.php
new file mode 100644
index 0000000..0c99ec1
--- /dev/null
+++ b/src/StatusProviderInterface.php
@@ -0,0 +1,8 @@
+<?php
+
+namespace Tobscure\JsonApiServer;
+
+interface StatusProviderInterface
+{
+    public function getJsonApiStatus(): array;
+}
diff --git a/tests/CreateTest.php b/tests/CreateTest.php
index d35ef1f..be95e13 100644
--- a/tests/CreateTest.php
+++ b/tests/CreateTest.php
@@ -118,14 +118,14 @@ class CreateTest extends AbstractTestCase
             $schema->attribute('writable1')->writable();
 
             $schema->attribute('writable2')->writableIf(function ($arg1, $arg2) use ($adapter, $request) {
-                $this->assertEquals($adapter->createdModel, $arg1);
-                $this->assertEquals($request, $arg2);
+                $this->assertEquals($request, $arg1);
+                $this->assertEquals($adapter->createdModel, $arg2);
                 return true;
             });
 
             $schema->attribute('writable3')->readonlyIf(function ($arg1, $arg2) use ($adapter, $request) {
-                $this->assertEquals($adapter->createdModel, $arg1);
-                $this->assertEquals($request, $arg2);
+                $this->assertEquals($request, $arg1);
+                $this->assertEquals($adapter->createdModel, $arg2);
                 return false;
             });
         });
diff --git a/tests/MockAdapter.php b/tests/MockAdapter.php
index c9b150e..c88c785 100644
--- a/tests/MockAdapter.php
+++ b/tests/MockAdapter.php
@@ -4,6 +4,7 @@ namespace Tobscure\Tests\JsonApiServer;
 
 use Tobscure\JsonApiServer\Adapter\AdapterInterface;
 use Tobscure\JsonApiServer\Schema\Attribute;
+use Tobscure\JsonApiServer\Schema\Field;
 use Tobscure\JsonApiServer\Schema\HasMany;
 use Tobscure\JsonApiServer\Schema\HasOne;
 
@@ -44,27 +45,27 @@ class MockAdapter implements AdapterInterface
 
     public function getAttribute($model, Attribute $attribute)
     {
-        return $model->{$attribute->property} ?? 'default';
+        return $model->{$this->getProperty($attribute)} ?? 'default';
     }
 
     public function getHasOne($model, HasOne $relationship)
     {
-        return $model->{$relationship->property} ?? null;
+        return $model->{$this->getProperty($relationship)} ?? null;
     }
 
     public function getHasMany($model, HasMany $relationship): array
     {
-        return $model->{$relationship->property} ?? [];
+        return $model->{$this->getProperty($relationship)} ?? [];
     }
 
     public function applyAttribute($model, Attribute $attribute, $value)
     {
-        $model->{$attribute->property} = $value;
+        $model->{$this->getProperty($attribute)} = $value;
     }
 
     public function applyHasOne($model, HasOne $relationship, $related)
     {
-        $model->{$relationship->property} = $related;
+        $model->{$this->getProperty($relationship)} = $related;
     }
 
     public function save($model)
@@ -120,4 +121,9 @@ class MockAdapter implements AdapterInterface
     {
         $model->load[] = $relationships;
     }
+
+    private function getProperty(Field $field)
+    {
+        return $field->property ?: $field->name;
+    }
 }
diff --git a/tests/ShowTest.php b/tests/ShowTest.php
index a00bd29..9f22dac 100644
--- a/tests/ShowTest.php
+++ b/tests/ShowTest.php
@@ -93,8 +93,8 @@ class ShowTest extends AbstractTestCase
         $api->resource('users', $adapter, function (Builder $schema) use ($model, $request) {
             $schema->attribute('attribute1')
                 ->get(function ($arg1, $arg2) use ($model, $request) {
-                    $this->assertEquals($model, $arg1);
-                    $this->assertEquals($request, $arg2);
+                    $this->assertEquals($request, $arg1);
+                    $this->assertEquals($model, $arg2);
                     return 'value1';
                 });
         });
@@ -127,14 +127,14 @@ class ShowTest extends AbstractTestCase
             $schema->attribute('visible2')->visible();
 
             $schema->attribute('visible3')->visibleIf(function ($arg1, $arg2) use ($model, $request) {
-                $this->assertEquals($model, $arg1);
-                $this->assertEquals($request, $arg2);
+                $this->assertEquals($request, $arg1);
+                $this->assertEquals($model, $arg2);
                 return true;
             });
 
             $schema->attribute('visible4')->hiddenIf(function ($arg1, $arg2) use ($model, $request) {
-                $this->assertEquals($model, $arg1);
-                $this->assertEquals($request, $arg2);
+                $this->assertEquals($request, $arg1);
+                $this->assertEquals($model, $arg2);
                 return false;
             });