diff --git a/src/Context/CurrentContext.php b/src/Context/CurrentContext.php
index 19331d1..22a08f4 100644
--- a/src/Context/CurrentContext.php
+++ b/src/Context/CurrentContext.php
@@ -15,7 +15,7 @@ use Symfony\Component\HttpFoundation\RequestStack;
  *
  * @internal
  */
-class CurrentContext implements CurrentContextInterface {
+class CurrentContext {
 
   /**
    * The JSON API resource type repository.
diff --git a/src/Context/CurrentContextInterface.php b/src/Context/CurrentContextInterface.php
deleted file mode 100644
index 25ae56e..0000000
--- a/src/Context/CurrentContextInterface.php
+++ /dev/null
@@ -1,64 +0,0 @@
-<?php
-
-namespace Drupal\jsonapi\Context;
-
-/**
- * Interface CurrentContextInterface.
- *
- * An interface for accessing contextual information for the current request.
- *
- * @package \Drupal\jsonapi\Context
- *
- * @internal
- */
-interface CurrentContextInterface {
-
-  /**
-   * Gets the JSON API resource type for the current request.
-   *
-   * @return \Drupal\jsonapi\ResourceType\ResourceType
-   *   The JSON API resource type for the current request.
-   */
-  public function getResourceType();
-
-  /**
-   * Checks if the request is on a relationship.
-   *
-   * @return bool
-   *   TRUE if the request is on a relationship. FALSE otherwise.
-   */
-  public function isOnRelationship();
-
-  /**
-   * Get a value by key from the _json_api_params route parameter.
-   *
-   * @param string $parameter_key
-   *   The key by which to retrieve a route parameter.
-   *
-   * @return mixed
-   *   The JSON API provided parameter.
-   */
-  public function getJsonApiParameter($parameter_key);
-
-  /**
-   * Determines, whether the JSONAPI extension was requested.
-   *
-   * @todo Find a better place for such a JSONAPI derived information.
-   *
-   * @param string $extension_name
-   *   The extension name.
-   *
-   * @return bool
-   *   Returns TRUE, if the extension has been found.
-   */
-  public function hasExtension($extension_name);
-
-  /**
-   * Returns a list of requested extensions.
-   *
-   * @return string[]
-   *   The extension names.
-   */
-  public function getExtensions();
-
-}
diff --git a/src/Context/FieldResolver.php b/src/Context/FieldResolver.php
index 2a4f654..d946984 100644
--- a/src/Context/FieldResolver.php
+++ b/src/Context/FieldResolver.php
@@ -12,12 +12,12 @@ use Drupal\jsonapi\Error\SerializableHttpException;
  *
  * @internal
  */
-class FieldResolver implements FieldResolverInterface {
+class FieldResolver {
 
   /**
    * The entity type id.
    *
-   * @var \Drupal\jsonapi\Context\CurrentContextInterface
+   * @var \Drupal\jsonapi\Context\CurrentContext
    */
   protected $currentContext;
 
@@ -31,12 +31,12 @@ class FieldResolver implements FieldResolverInterface {
   /**
    * Creates a FieldResolver instance.
    *
-   * @param \Drupal\jsonapi\Context\CurrentContextInterface $current_context
+   * @param \Drupal\jsonapi\Context\CurrentContext $current_context
    *   The JSON API CurrentContext service.
    * @param \Drupal\Core\Entity\EntityFieldManagerInterface $field_manager
    *   The field manager.
    */
-  public function __construct(CurrentContextInterface $current_context, EntityFieldManagerInterface $field_manager) {
+  public function __construct(CurrentContext $current_context, EntityFieldManagerInterface $field_manager) {
     $this->currentContext = $current_context;
     $this->fieldManager = $field_manager;
   }
diff --git a/src/Context/FieldResolverInterface.php b/src/Context/FieldResolverInterface.php
deleted file mode 100644
index 4d3622b..0000000
--- a/src/Context/FieldResolverInterface.php
+++ /dev/null
@@ -1,42 +0,0 @@
-<?php
-
-namespace Drupal\jsonapi\Context;
-
-/**
- * Contains FieldResolverInterface.
- *
- * Interface for mapping public field names to Drupal field names.
- *
- * @internal
- */
-interface FieldResolverInterface {
-
-  /**
-   * Maps a Drupal field name to a public field name.
-   *
-   * Example:
-   *   'field_author.entity.field_first_name' -> 'author.firstName'.
-   *
-   * @param string $field_name
-   *   The Drupal field name to map to a public field name.
-   *
-   * @return string
-   *   The mapped field name.
-   */
-  public function resolveExternal($field_name);
-
-  /**
-   * Maps a public field name to a Drupal field name.
-   *
-   * Example:
-   *   'author.firstName' -> 'field_author.entity.field_first_name'.
-   *
-   * @param string $field_name
-   *   The publicI field name to map to a Drupal field name.
-   *
-   * @return string
-   *   The mapped field name.
-   */
-  public function resolveInternal($field_name);
-
-}
diff --git a/src/Controller/EntityResource.php b/src/Controller/EntityResource.php
index 4b016fb..987ec5b 100644
--- a/src/Controller/EntityResource.php
+++ b/src/Controller/EntityResource.php
@@ -21,7 +21,7 @@ use Drupal\jsonapi\ResourceType\ResourceType;
 use Drupal\jsonapi\Error\SerializableHttpException;
 use Drupal\jsonapi\Error\UnprocessableHttpEntityException;
 use Drupal\jsonapi\Query\QueryBuilderInterface;
-use Drupal\jsonapi\Context\CurrentContextInterface;
+use Drupal\jsonapi\Context\CurrentContext;
 use Drupal\jsonapi\ResourceResponse;
 use Drupal\jsonapi\Routing\Param\JsonApiParamBase;
 use Drupal\jsonapi\Routing\Param\OffsetPage;
@@ -66,7 +66,7 @@ class EntityResource {
   /**
    * The current context service.
    *
-   * @var \Drupal\jsonapi\Context\CurrentContextInterface
+   * @var \Drupal\jsonapi\Context\CurrentContext
    */
   protected $currentContext;
 
@@ -88,12 +88,12 @@ class EntityResource {
    *   The query builder.
    * @param \Drupal\Core\Entity\EntityFieldManagerInterface $field_manager
    *   The entity type field manager.
-   * @param \Drupal\jsonapi\Context\CurrentContextInterface $current_context
+   * @param \Drupal\jsonapi\Context\CurrentContext $current_context
    *   The current context.
    * @param \Drupal\Core\Field\FieldTypePluginManagerInterface $plugin_manager
    *   The plugin manager for fields.
    */
-  public function __construct(ResourceType $resource_type, EntityTypeManagerInterface $entity_type_manager, QueryBuilderInterface $query_builder, EntityFieldManagerInterface $field_manager, CurrentContextInterface $current_context, FieldTypePluginManagerInterface $plugin_manager) {
+  public function __construct(ResourceType $resource_type, EntityTypeManagerInterface $entity_type_manager, QueryBuilderInterface $query_builder, EntityFieldManagerInterface $field_manager, CurrentContext $current_context, FieldTypePluginManagerInterface $plugin_manager) {
     $this->resourceType = $resource_type;
     $this->entityTypeManager = $entity_type_manager;
     $this->queryBuilder = $query_builder;
diff --git a/src/Controller/RequestHandler.php b/src/Controller/RequestHandler.php
index ddabb93..819c5f9 100644
--- a/src/Controller/RequestHandler.php
+++ b/src/Controller/RequestHandler.php
@@ -5,7 +5,7 @@ namespace Drupal\jsonapi\Controller;
 use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
 use Drupal\Core\Render\RenderContext;
 use Drupal\Core\Routing\RouteMatchInterface;
-use Drupal\jsonapi\Context\CurrentContextInterface;
+use Drupal\jsonapi\Context\CurrentContext;
 use Drupal\jsonapi\Error\ErrorHandlerInterface;
 use Drupal\jsonapi\Error\SerializableHttpException;
 use Drupal\jsonapi\ResourceResponse;
@@ -52,7 +52,7 @@ class RequestHandler implements ContainerAwareInterface, ContainerInjectionInter
     // Deserialize incoming data if available.
     /* @var \Symfony\Component\Serializer\SerializerInterface $serializer */
     $serializer = $this->container->get('serializer');
-    /* @var \Drupal\jsonapi\Context\CurrentContextInterface $current_context */
+    /* @var \Drupal\jsonapi\Context\CurrentContext $current_context */
     $current_context = $this->container->get('jsonapi.current_context');
     $unserialized = $this->deserializeBody($request, $serializer, $route->getOption('serialization_class'), $current_context);
     $format = $request->getRequestFormat();
@@ -170,13 +170,13 @@ class RequestHandler implements ContainerAwareInterface, ContainerInjectionInter
    *   The serializer for the deserialization of the input data.
    * @param string $serialization_class
    *   The class the input data needs to deserialize into.
-   * @param \Drupal\jsonapi\Context\CurrentContextInterface $current_context
+   * @param \Drupal\jsonapi\Context\CurrentContext $current_context
    *   The current context
    *
    * @return mixed
    *   The deserialized data or a Response object in case of error.
    */
-  public function deserializeBody(Request $request, SerializerInterface $serializer, $serialization_class, CurrentContextInterface $current_context) {
+  public function deserializeBody(Request $request, SerializerInterface $serializer, $serialization_class, CurrentContext $current_context) {
     $received = $request->getContent();
     $method = strtolower($request->getMethod());
     if (empty($received)) {
@@ -252,13 +252,13 @@ class RequestHandler implements ContainerAwareInterface, ContainerInjectionInter
    *
    * @param \Symfony\Component\Routing\Route $route
    *   The matched route.
-   * @param \Drupal\jsonapi\Context\CurrentContextInterface $current_context
+   * @param \Drupal\jsonapi\Context\CurrentContext $current_context
    *   The current context.
    *
    * @return \Drupal\jsonapi\Controller\EntityResource
    *   The instantiated resource.
    */
-  protected function resourceFactory(Route $route, CurrentContextInterface $current_context) {
+  protected function resourceFactory(Route $route, CurrentContext $current_context) {
     /** @var \Drupal\jsonapi\ResourceType\ResourceTypeRepository $resource_type_repository */
     $resource_type_repository = $this->container->get('jsonapi.resource_type.repository');
     /* @var \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager */
diff --git a/src/Normalizer/JsonApiDocumentTopLevelNormalizer.php b/src/Normalizer/JsonApiDocumentTopLevelNormalizer.php
index 22798a4..26b7ec1 100644
--- a/src/Normalizer/JsonApiDocumentTopLevelNormalizer.php
+++ b/src/Normalizer/JsonApiDocumentTopLevelNormalizer.php
@@ -4,7 +4,7 @@ namespace Drupal\jsonapi\Normalizer;
 
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Field\EntityReferenceFieldItemListInterface;
-use Drupal\jsonapi\Context\CurrentContextInterface;
+use Drupal\jsonapi\Context\CurrentContext;
 use Drupal\jsonapi\Normalizer\Value\DocumentRootNormalizerValue;
 use Drupal\jsonapi\Resource\EntityCollectionInterface;
 use Drupal\jsonapi\LinkManager\LinkManagerInterface;
@@ -35,7 +35,7 @@ class JsonApiDocumentTopLevelNormalizer extends NormalizerBase implements Denorm
   /**
    * The current JSON API request context.
    *
-   * @var \Drupal\jsonapi\Context\CurrentContextInterface
+   * @var \Drupal\jsonapi\Context\CurrentContext
    */
   protected $currentContext;
 
@@ -51,12 +51,12 @@ class JsonApiDocumentTopLevelNormalizer extends NormalizerBase implements Denorm
    *
    * @param \Drupal\jsonapi\LinkManager\LinkManagerInterface $link_manager
    *   The link manager to get the links.
-   * @param \Drupal\jsonapi\Context\CurrentContextInterface $current_context
+   * @param \Drupal\jsonapi\Context\CurrentContext $current_context
    *   The current context.
    * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
    *   The entity type manager.
    */
-  public function __construct(LinkManagerInterface $link_manager, CurrentContextInterface $current_context, EntityTypeManagerInterface $entity_type_manager) {
+  public function __construct(LinkManagerInterface $link_manager, CurrentContext $current_context, EntityTypeManagerInterface $entity_type_manager) {
     $this->linkManager = $link_manager;
     $this->currentContext = $current_context;
     $this->entityTypeManager = $entity_type_manager;
diff --git a/src/Query/QueryBuilder.php b/src/Query/QueryBuilder.php
index 17479d9..e835138 100644
--- a/src/Query/QueryBuilder.php
+++ b/src/Query/QueryBuilder.php
@@ -8,8 +8,8 @@ use Drupal\jsonapi\Error\SerializableHttpException;
 use Drupal\jsonapi\Routing\Param\OffsetPage;
 use Drupal\jsonapi\Routing\Param\Filter;
 use Drupal\jsonapi\Routing\Param\JsonApiParamInterface;
-use Drupal\jsonapi\Context\CurrentContextInterface;
-use Drupal\jsonapi\Context\FieldResolverInterface;
+use Drupal\jsonapi\Context\CurrentContext;
+use Drupal\jsonapi\Context\FieldResolver;
 use Drupal\jsonapi\Routing\Param\Sort;
 
 /**
@@ -41,14 +41,14 @@ class QueryBuilder implements QueryBuilderInterface {
   /**
    * The JSON API current context service.
    *
-   * @var \Drupal\jsonapi\Context\CurrentContextInterface
+   * @var \Drupal\jsonapi\Context\CurrentContext
    */
   protected $currentContext;
 
   /**
    * The field resolver service.
    *
-   * @var \Drupal\jsonapi\Context\FieldResolverInterface
+   * @var \Drupal\jsonapi\Context\FieldResolver
    */
   protected $fieldResolver;
 
@@ -57,12 +57,12 @@ class QueryBuilder implements QueryBuilderInterface {
    *
    * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
    *   An instance of a QueryFactory.
-   * @param \Drupal\jsonapi\Context\CurrentContextInterface $current_context
+   * @param \Drupal\jsonapi\Context\CurrentContext $current_context
    *   An instance of the current context service.
-   * @param \Drupal\jsonapi\Context\FieldResolverInterface $field_resolver
+   * @param \Drupal\jsonapi\Context\FieldResolver $field_resolver
    *   The field resolver service.
    */
-  public function __construct(EntityTypeManagerInterface $entity_type_manager, CurrentContextInterface $current_context, FieldResolverInterface $field_resolver) {
+  public function __construct(EntityTypeManagerInterface $entity_type_manager, CurrentContext $current_context, FieldResolver $field_resolver) {
     $this->entityTypeManager = $entity_type_manager;
     $this->currentContext = $current_context;
     $this->fieldResolver = $field_resolver;
diff --git a/tests/src/Unit/Context/FieldResolverTest.php b/tests/src/Unit/Context/FieldResolverTest.php
index 255cc2a..ca4a522 100644
--- a/tests/src/Unit/Context/FieldResolverTest.php
+++ b/tests/src/Unit/Context/FieldResolverTest.php
@@ -7,7 +7,7 @@ use Drupal\Tests\UnitTestCase;
 use Drupal\Core\Entity\EntityFieldManagerInterface;
 use Drupal\Core\Field\FieldStorageDefinitionInterface;
 use Drupal\jsonapi\Context\FieldResolver;
-use Drupal\jsonapi\Context\CurrentContextInterface;
+use Drupal\jsonapi\Context\CurrentContext;
 
 /**
  * Class FieldResolverTest.
@@ -23,7 +23,7 @@ class FieldResolverTest extends UnitTestCase {
   /**
    * A mock for the current context service.
    *
-   * @var \Drupal\jsonapi\Context\CurrentContextInterface
+   * @var \Drupal\jsonapi\Context\CurrentContext
    */
   protected $currentContext;
 
@@ -38,7 +38,7 @@ class FieldResolverTest extends UnitTestCase {
    * {@inheritdoc}
    */
   public function setUp() {
-    $current_context = $this->prophesize(CurrentContextInterface::class);
+    $current_context = $this->prophesize(CurrentContext::class);
 
     $current_context->getResourceType()
       ->willReturn(new ResourceType('lorem', $this->randomMachineName(), NULL));
diff --git a/tests/src/Unit/Controller/RequestHandlerTest.php b/tests/src/Unit/Controller/RequestHandlerTest.php
index f23cf8a..2316de4 100644
--- a/tests/src/Unit/Controller/RequestHandlerTest.php
+++ b/tests/src/Unit/Controller/RequestHandlerTest.php
@@ -4,7 +4,7 @@ namespace Drupal\Tests\jsonapi\Unit\Controller;
 
 use Drupal\Core\Entity\EntityStorageInterface;
 use Drupal\jsonapi\ResourceType\ResourceType;
-use Drupal\jsonapi\Context\CurrentContextInterface;
+use Drupal\jsonapi\Context\CurrentContext;
 use Drupal\jsonapi\Controller\RequestHandler;
 use Drupal\Tests\UnitTestCase;
 use Prophecy\Argument;
@@ -43,7 +43,7 @@ class RequestHandlerTest extends UnitTestCase {
       ->willThrow(new UnexpectedValueException('Foo'));
     $serializer->serialize(Argument::any(), Argument::any(), Argument::any())
       ->willReturn('{"errors":[{"status":422,"message":"Foo"}]}');
-    $current_context = $this->prophesize(CurrentContextInterface::class);
+    $current_context = $this->prophesize(CurrentContext::class);
     $current_context->getResourceType()
       ->willReturn(new ResourceType($this->randomMachineName(), $this->randomMachineName(), NULL));
     try {
diff --git a/tests/src/Unit/Normalizer/JsonApiDocumentTopLevelNormalizerTest.php b/tests/src/Unit/Normalizer/JsonApiDocumentTopLevelNormalizerTest.php
index 1311feb..7673001 100644
--- a/tests/src/Unit/Normalizer/JsonApiDocumentTopLevelNormalizerTest.php
+++ b/tests/src/Unit/Normalizer/JsonApiDocumentTopLevelNormalizerTest.php
@@ -9,7 +9,7 @@ use Drupal\Core\Entity\FieldableEntityInterface;
 use Drupal\jsonapi\ResourceType\ResourceType;
 use Drupal\jsonapi\Normalizer\JsonApiDocumentTopLevelNormalizer;
 use Drupal\jsonapi\LinkManager\LinkManagerInterface;
-use Drupal\jsonapi\Context\CurrentContextInterface;
+use Drupal\jsonapi\Context\CurrentContext;
 use Drupal\Tests\UnitTestCase;
 use Prophecy\Argument;
 use Symfony\Component\Routing\Route;
@@ -34,7 +34,7 @@ class JsonApiDocumentTopLevelNormalizerTest extends UnitTestCase {
    */
   public function setUp() {
     $link_manager = $this->prophesize(LinkManagerInterface::class);
-    $current_context_manager = $this->prophesize(CurrentContextInterface::class);
+    $current_context_manager = $this->prophesize(CurrentContext::class);
 
     $entity_storage = $this->prophesize(EntityStorageInterface::class);
     $self = $this;