diff --git a/composer.json b/composer.json
index 20a22a4..4456728 100644
--- a/composer.json
+++ b/composer.json
@@ -8,6 +8,7 @@
         "ext-iconv": "*",
         "ext-json": "*",
         "nesbot/carbon": "^1.33",
+        "ocramius/proxy-manager": "^2.2",
         "sensio/framework-extra-bundle": "^5.2",
         "symfony/console": "*",
         "symfony/flex": "^1.1",
diff --git a/composer.lock b/composer.lock
index 99880b7..3683b64 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "0af7567013958485d4223a33f8ba099a",
+    "content-hash": "23c4b2debfec2fc7da526a8bd2007ec3",
     "packages": [
         {
             "name": "doctrine/annotations",
diff --git a/config/services.yaml b/config/services.yaml
index 0ea34cb..279dc5f 100644
--- a/config/services.yaml
+++ b/config/services.yaml
@@ -31,10 +31,32 @@ services:
         resource: '../src/Provider'
         public: true
 
+    # add more service definitions when explicit configuration is needed
+    # please note that last definitions always *replace* previous ones
+
+    #proxy configuration
+    proxy.locator:
+        class: 'ProxyManager\FileLocator\FileLocator'
+        arguments: ['%kernel.cache_dir%/proxy']
+
+    proxy.strategy:
+        class: 'ProxyManager\GeneratorStrategy\FileWriterGeneratorStrategy'
+        arguments: ['@proxy.locator']
+
+    proxy.config:
+        class: 'ProxyManager\Configuration'
+        calls:
+        - ['setGeneratorStrategy', ['@proxy.strategy']]
+        - ['setProxiesTargetDir', ['%kernel.cache_dir%/proxy']]
+
+    ProxyManager\Configuration: '@proxy.config'
+
+    # serializer configuration
     serializer.datetime_normalizer:
         class: Symfony\Component\Serializer\Normalizer\DateTimeNormalizer
         arguments: [!php/const DateTime::ATOM]
-        tags:  [serializer.normalizer]
+        tags: [serializer.normalizer]
 
-    # add more service definitions when explicit configuration is needed
-    # please note that last definitions always *replace* previous ones
+    App\Service\Normalizer\:
+        resource: '../src/Service/Normalizer'
+        tags: [serializer.normalizer]
diff --git a/src/Entity/TrackEntity.php b/src/Entity/TrackEntity.php
index 833c71a..b3d2482 100644
--- a/src/Entity/TrackEntity.php
+++ b/src/Entity/TrackEntity.php
@@ -46,7 +46,7 @@ class TrackEntity implements Entity, Fillable
      * Stops in track
      * @var Collection
      * @ORM\OneToMany(targetEntity=StopInTrack::class, mappedBy="track", cascade={"persist"})
-     * @ORM\OrderBy({"order"})
+     * @ORM\OrderBy({"order": "ASC"})
      */
     private $stopsInTrack;
 
diff --git a/src/Kernel.php b/src/Kernel.php
index dc2f242..fa55da6 100644
--- a/src/Kernel.php
+++ b/src/Kernel.php
@@ -48,6 +48,10 @@ class Kernel extends BaseKernel
         $loader->load($confDir.'/{packages}/'.$this->environment.'/**/*'.self::CONFIG_EXTS, 'glob');
         $loader->load($confDir.'/{services}'.self::CONFIG_EXTS, 'glob');
         $loader->load($confDir.'/{services}_'.$this->environment.self::CONFIG_EXTS, 'glob');
+
+        if (!file_exists($this->getCacheDir().'/proxy')) {
+            mkdir($this->getCacheDir().'/proxy');
+        }
     }
 
     protected function configureRoutes(RouteCollectionBuilder $routes)
diff --git a/src/Model/Line.php b/src/Model/Line.php
index 9d17a9f..917913b 100644
--- a/src/Model/Line.php
+++ b/src/Model/Line.php
@@ -2,12 +2,9 @@
 
 namespace App\Model;
 
-use Symfony\Component\Serializer\Normalizer\NormalizableInterface;
-use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
-use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
 use Tightenco\Collect\Support\Collection;
 
-class Line implements Fillable, Referable, NormalizableInterface
+class Line implements Fillable, Referable
 {
     const TYPE_TRAM       = 'tram';
     const TYPE_BUS        = 'bus';
@@ -120,12 +117,4 @@ class Line implements Fillable, Referable, NormalizableInterface
     {
         $this->operator = $operator;
     }
-
-    public function normalize(NormalizerInterface $normalizer, $format = null, array $context = [])
-    {
-        $normalizer = new ObjectNormalizer();
-        $normalizer->setIgnoredAttributes(['tracks']);
-
-        return $normalizer->normalize($this);
-    }
 }
\ No newline at end of file
diff --git a/src/Model/Stop.php b/src/Model/Stop.php
index 4d0ee1f..aeaa429 100644
--- a/src/Model/Stop.php
+++ b/src/Model/Stop.php
@@ -2,6 +2,7 @@
 
 namespace App\Model;
 
+use Symfony\Component\Serializer\Annotation\Groups;
 use Symfony\Component\Serializer\Normalizer\NormalizableInterface;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 use Tightenco\Collect\Support\Arr;
@@ -76,6 +77,7 @@ class Stop implements Referable, Fillable, NormalizableInterface
         $this->variant = $variant;
     }
 
+    /** @Groups({"hidden"}) */
     public function getLatitude(): ?float
     {
         return $this->latitude;
@@ -86,6 +88,7 @@ class Stop implements Referable, Fillable, NormalizableInterface
         $this->latitude = $latitude;
     }
 
+    /** @Groups({"hidden"}) */
     public function getLongitude(): ?float
     {
         return $this->longitude;
diff --git a/src/Provider/Database/DatabaseRepository.php b/src/Provider/Database/DatabaseRepository.php
index 18b622b..1581733 100644
--- a/src/Provider/Database/DatabaseRepository.php
+++ b/src/Provider/Database/DatabaseRepository.php
@@ -2,9 +2,12 @@
 
 namespace App\Provider\Database;
 
+use App\Entity\Entity;
 use App\Entity\ProviderEntity;
+use App\Service\EntityConverter;
 use App\Service\IdUtils;
 use Doctrine\ORM\EntityManagerInterface;
+use Kadet\Functional as f;
 
 class DatabaseRepository
 {
@@ -17,15 +20,19 @@ class DatabaseRepository
     /** @var IdUtils */
     protected $id;
 
+    /** @var EntityConverter */
+    protected $converter;
+
     /**
      * DatabaseRepository constructor.
      *
      * @param EntityManagerInterface $em
      */
-    public function __construct(EntityManagerInterface $em, IdUtils $id)
+    public function __construct(EntityManagerInterface $em, IdUtils $id, EntityConverter $converter)
     {
-        $this->em = $em;
-        $this->id = $id;
+        $this->em        = $em;
+        $this->id        = $id;
+        $this->converter = $converter;
     }
 
     /** @return static */
@@ -36,4 +43,9 @@ class DatabaseRepository
 
         return $result;
     }
+
+    protected function convert(Entity $entity)
+    {
+        return $this->converter->convert($entity);
+    }
 }
\ No newline at end of file
diff --git a/src/Provider/Database/GenericLineRepository.php b/src/Provider/Database/GenericLineRepository.php
index 94235f6..e9bab49 100644
--- a/src/Provider/Database/GenericLineRepository.php
+++ b/src/Provider/Database/GenericLineRepository.php
@@ -33,15 +33,4 @@ class GenericLineRepository extends DatabaseRepository implements LineRepository
 
         return collect($lines)->map(f\ref([$this, 'convert']));
     }
-
-    private function convert(LineEntity $line): Line
-    {
-        return Line::createFromArray([
-            'id'       => $this->id->of($line),
-            'symbol'   => $line->getSymbol(),
-            'night'    => $line->isNight(),
-            'fast'     => $line->isFast(),
-            'type'     => $line->getType()
-        ]);
-    }
 }
\ No newline at end of file
diff --git a/src/Provider/Database/GenericStopRepository.php b/src/Provider/Database/GenericStopRepository.php
index 2ed9efb..25bd674 100644
--- a/src/Provider/Database/GenericStopRepository.php
+++ b/src/Provider/Database/GenericStopRepository.php
@@ -15,7 +15,7 @@ class GenericStopRepository extends DatabaseRepository implements StopRepository
     {
         $stops = $this->em->getRepository(StopEntity::class)->findAll();
 
-        return collect($stops)->map(\Closure::fromCallable([$this, 'convert']));
+        return collect($stops)->map(f\ref([$this, 'convert']));
     }
 
     public function getAllGroups(): Collection
@@ -36,7 +36,7 @@ class GenericStopRepository extends DatabaseRepository implements StopRepository
         $ids = collect($ids)->map(f\apply(f\ref([$this->id, 'generate']), $this->provider));
 
         $stops = $this->em->getRepository(StopEntity::class)->findBy(['id' => $ids->all()]);
-        return collect($stops)->map(\Closure::fromCallable([$this, 'convert']));
+        return collect($stops)->map(f\ref([$this, 'convert']));
     }
 
     public function findGroupsByName(string $name): Collection
@@ -47,26 +47,11 @@ class GenericStopRepository extends DatabaseRepository implements StopRepository
             ->where('s.name LIKE :name')
             ->getQuery();
 
-        $stops = collect($query->execute([':name' => "%$name%"]))->map(\Closure::fromCallable([$this, 'convert']));
+        $stops = collect($query->execute([':name' => "%$name%"]))->map(f\ref([$this, 'convert']));
 
         return $this->group($stops);
     }
 
-    private function convert(StopEntity $entity): Stop
-    {
-        return Stop::createFromArray([
-            'id'          => $this->id->of($entity),
-            'name'        => $entity->getName(),
-            'description' => $entity->getDescription(),
-            'variant'     => $entity->getVariant(),
-            'onDemand'    => $entity->isOnDemand(),
-            'location'    => [
-                $entity->getLatitude(),
-                $entity->getLongitude(),
-            ],
-        ]);
-    }
-
     private function group(Collection $stops)
     {
         return $stops->groupBy(function (Stop $stop) {
diff --git a/src/Service/EntityConverter.php b/src/Service/EntityConverter.php
new file mode 100644
index 0000000..a50d61f
--- /dev/null
+++ b/src/Service/EntityConverter.php
@@ -0,0 +1,151 @@
+<?php
+
+namespace App\Service;
+
+use App\Entity\Entity;
+use App\Entity\LineEntity;
+use App\Entity\OperatorEntity;
+use App\Entity\StopEntity;
+use App\Entity\TrackEntity;
+use App\Model\Line;
+use App\Model\Operator;
+use App\Model\Stop;
+use App\Model\Track;
+use App\Service\Proxy\ReferenceObjectFactory;
+use Doctrine\ORM\PersistentCollection;
+use Doctrine\ORM\Proxy\Proxy;
+use Kadet\Functional as f;
+use const Kadet\Functional\_;
+
+final class EntityConverter
+{
+    private $id;
+    private $reference;
+
+    public function __construct(IdUtils $id, ReferenceObjectFactory $reference)
+    {
+        $this->id        = $id;
+        $this->reference = $reference;
+    }
+
+    /**
+     * @param Entity $entity
+     * @param array  $cache
+     *
+     * @return Line|Track|Stop|Operator
+     */
+    public function convert(Entity $entity, array $cache = [])
+    {
+        if (array_key_exists($key = get_class($entity).':'.$this->getId($entity), $cache)) {
+            return $cache[$key];
+        }
+
+        if ($entity instanceof Proxy && !$entity->__isInitialized()) {
+            return $this->reference($entity);
+        }
+
+        $result  = $this->create($entity);
+        $cache   = $cache + [$key => $result];
+        $convert = f\partial([$this, 'convert'], _, $cache);
+
+        switch (true) {
+            case $entity instanceof OperatorEntity:
+                $result->fill([
+                    'name'  => $entity->getName(),
+                    'phone' => $entity->getPhone(),
+                    'email' => $entity->getEmail(),
+                    'url'   => $entity->getEmail(),
+                ]);
+                break;
+
+            case $entity instanceof LineEntity:
+                $result->fill([
+                    'id'       => $this->id->of($entity),
+                    'symbol'   => $entity->getSymbol(),
+                    'type'     => $entity->getType(),
+                    'operator' => $convert($entity->getOperator()),
+                    'tracks'   => $this->collection($entity->getTracks(), $convert),
+                ]);
+                break;
+
+            case $entity instanceof TrackEntity:
+                $result->fill([
+                    'variant'     => $entity->getVariant(),
+                    'description' => $entity->getDescription(),
+                    'stops'       => $this->collection($entity->getStops(), $convert),
+                    'line'        => $convert($entity->getLine()),
+                ]);
+                break;
+
+            case $entity instanceof StopEntity:
+                $result->fill([
+                    'name'        => $entity->getName(),
+                    'variant'     => $entity->getVariant(),
+                    'description' => $entity->getDescription(),
+                    'location'    => [
+                        $entity->getLatitude(),
+                        $entity->getLongitude(),
+                    ],
+                ]);
+        }
+
+        return $result;
+    }
+
+    // HACK to not trigger doctrine stupid lazy loading.
+    private function getId(Entity $entity) {
+        if ($entity instanceof Proxy) {
+            $id = (new \ReflectionClass(get_parent_class($entity)))->getProperty('id');
+            $id->setAccessible(true);
+
+            return $id->getValue($entity);
+        }
+
+        return $entity->getId();
+    }
+
+    private function collection(PersistentCollection $collection, $converter)
+    {
+        if ($collection->isInitialized()) {
+            return collect($collection)->map($converter);
+        }
+
+        return collect();
+    }
+
+    private function getModelClassForEntity(Entity $entity)
+    {
+        switch (true) {
+            case $entity instanceof OperatorEntity:
+                return Operator::class;
+
+            case $entity instanceof LineEntity:
+                return Line::class;
+
+            case $entity instanceof TrackEntity:
+                return Track::class;
+
+            case $entity instanceof StopEntity:
+                return Stop::class;
+
+            default:
+                return false;
+        }
+    }
+
+    private function create(Entity $entity)
+    {
+        $id = $this->id->of($entity);
+        $class = $this->getModelClassForEntity($entity);
+
+        return $class::createFromArray(['id' => $id]);
+    }
+
+    private function reference(Entity $entity)
+    {
+        $id = $this->id->strip($this->getId($entity));
+        $class = $this->getModelClassForEntity($entity);
+
+        return $this->reference->get($class, ['id' => $id]);
+    }
+}
\ No newline at end of file
diff --git a/src/Service/IdUtils.php b/src/Service/IdUtils.php
index d1fe477..61bc00b 100644
--- a/src/Service/IdUtils.php
+++ b/src/Service/IdUtils.php
@@ -7,18 +7,20 @@ use App\Entity\ProviderEntity;
 
 class IdUtils
 {
+    const DELIMITER = '::';
+
     public function generate(ProviderEntity $provider, $id)
     {
-        return sprintf('%s-%s', $provider->getId(), $id);
+        return sprintf('%s%s%s', $provider->getId(), self::DELIMITER, $id);
     }
 
-    public function strip(ProviderEntity $provider, $id)
+    public function strip($id)
     {
-        return substr($id, strlen($provider->getId()) + 1);
+        return explode(self::DELIMITER, $id)[1];
     }
 
     public function of(Entity $entity)
     {
-        return $this->strip($entity->getProvider(), $entity->getId());
+        return $this->strip($entity->getId());
     }
 }
\ No newline at end of file
diff --git a/src/Service/Normalizer/JustReferenceNormalizer.php b/src/Service/Normalizer/JustReferenceNormalizer.php
new file mode 100644
index 0000000..d30deea
--- /dev/null
+++ b/src/Service/Normalizer/JustReferenceNormalizer.php
@@ -0,0 +1,44 @@
+<?php
+
+namespace App\Service\Normalizer;
+
+use App\Model\JustReference;
+use Symfony\Component\Serializer\Exception\CircularReferenceException;
+use Symfony\Component\Serializer\Exception\InvalidArgumentException;
+use Symfony\Component\Serializer\Exception\LogicException;
+use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
+
+class JustReferenceNormalizer implements NormalizerInterface
+{
+    /**
+     * Normalizes an object into a set of arrays/scalars.
+     *
+     * @param mixed  $object  Object to normalize
+     * @param string $format  Format the normalization result will be encoded as
+     * @param array  $context Context options for the normalizer
+     *
+     * @return array|string|int|float|bool
+     *
+     * @throws InvalidArgumentException   Occurs when the object given is not an attempted type for the normalizer
+     * @throws CircularReferenceException Occurs when the normalizer detects a circular reference when no circular
+     *                                    reference handler can fix it
+     * @throws LogicException             Occurs when the normalizer is not called in an expected context
+     */
+    public function normalize($object, $format = null, array $context = [])
+    {
+        return [ 'id' => $object->getId() ];
+    }
+
+    /**
+     * Checks whether the given class is supported for normalization by this normalizer.
+     *
+     * @param mixed  $data   Data to normalize
+     * @param string $format The format being (de-)serialized from or into
+     *
+     * @return bool
+     */
+    public function supportsNormalization($data, $format = null)
+    {
+        return $data instanceof JustReference;
+    }
+}
\ No newline at end of file
diff --git a/src/Service/Normalizer/StopNormalizer.php b/src/Service/Normalizer/StopNormalizer.php
new file mode 100644
index 0000000..9a75a10
--- /dev/null
+++ b/src/Service/Normalizer/StopNormalizer.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace App\Service\Normalizer;
+
+use App\Model\Stop;
+use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
+use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
+use Tightenco\Collect\Support\Arr;
+
+class StopNormalizer implements NormalizerInterface
+{
+    private $normalizer;
+
+    public function __construct(ObjectNormalizer $normalizer)
+    {
+        $this->normalizer = $normalizer;
+    }
+
+    public function normalize($object, $format = null, array $context = [])
+    {
+        return Arr::except($this->normalizer->normalize($object), ['latitude', 'longitude']);
+    }
+
+    public function supportsNormalization($data, $format = null)
+    {
+        return $data instanceof Stop;
+    }
+}
\ No newline at end of file
diff --git a/src/Service/Proxy/ReferenceObjectFactory.php b/src/Service/Proxy/ReferenceObjectFactory.php
new file mode 100644
index 0000000..fdb0dd4
--- /dev/null
+++ b/src/Service/Proxy/ReferenceObjectFactory.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace App\Service\Proxy;
+
+use ProxyManager\Factory\AbstractBaseFactory;
+use ProxyManager\ProxyGenerator\ProxyGeneratorInterface;
+
+class ReferenceObjectFactory extends AbstractBaseFactory
+{
+    public function get($class, $id)
+    {
+        $id = is_array($id) ? $id : compact('id');
+
+        $proxy = $this->generateProxy($class);
+
+        $object = new $proxy();
+        $object->fill($id);
+        return $object;
+    }
+
+    protected function getGenerator(): ProxyGeneratorInterface
+    {
+        return new ReferenceObjectGenerator();
+    }
+}
\ No newline at end of file
diff --git a/src/Service/Proxy/ReferenceObjectGenerator.php b/src/Service/Proxy/ReferenceObjectGenerator.php
new file mode 100644
index 0000000..0dad49f
--- /dev/null
+++ b/src/Service/Proxy/ReferenceObjectGenerator.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace App\Service\Proxy;
+
+use App\Model\JustReference;
+use ProxyManager\ProxyGenerator\ProxyGeneratorInterface;
+use ReflectionClass;
+use Zend\Code\Generator\ClassGenerator;
+
+class ReferenceObjectGenerator implements ProxyGeneratorInterface
+{
+    public function generate(ReflectionClass $class, ClassGenerator $generator)
+    {
+        $interfaces = array_merge($class->getInterfaceNames(), [ JustReference::class ]);
+
+        $generator->setExtendedClass($class->getName());
+        $generator->setImplementedInterfaces($interfaces);
+    }
+}
\ No newline at end of file