diff --git a/src/Bundle/ChillCalendarBundle/Entity/Calendar.php b/src/Bundle/ChillCalendarBundle/Entity/Calendar.php
index f23f07610..24cd0f758 100644
--- a/src/Bundle/ChillCalendarBundle/Entity/Calendar.php
+++ b/src/Bundle/ChillCalendarBundle/Entity/Calendar.php
@@ -44,6 +44,9 @@ use function in_array;
  *     uniqueConstraints={@ORM\UniqueConstraint(name="idx_calendar_remote", columns={"remoteId"}, options={"where": "remoteId <> ''"})}
  * )
  * @ORM\Entity
+ * @Serializer\DiscriminatorMap(typeProperty="type", mapping={
+ *     "chill_calendar_calendar": Calendar::class
+ * })
  */
 class Calendar implements TrackCreationInterface, TrackUpdateInterface
 {
@@ -109,13 +112,13 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
 
     /**
      * @ORM\Embedded(class=CommentEmbeddable::class, columnPrefix="comment_")
-     * @Serializer\Groups({"calendar:read", "read"})
+     * @Serializer\Groups({"calendar:read", "read", "docgen:read"})
      */
     private CommentEmbeddable $comment;
 
     /**
      * @ORM\Column(type="datetime_immutable", nullable=false)
-     * @Serializer\Groups({"calendar:read", "read", "calendar:light"})
+     * @Serializer\Groups({"calendar:read", "read", "calendar:light", "docgen:read"})
      * @Assert\NotNull(message="calendar.An end date is required")
      */
     private ?DateTimeImmutable $endDate = null;
@@ -124,7 +127,7 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
      * @ORM\Id
      * @ORM\GeneratedValue
      * @ORM\Column(type="integer")
-     * @Serializer\Groups({"calendar:read", "read", "calendar:light"})
+     * @Serializer\Groups({"calendar:read", "read", "calendar:light", "docgen:read"})
      */
     private ?int $id = null;
 
@@ -136,20 +139,20 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
      *     cascade={"persist", "remove", "merge", "detach"}
      * )
      * @ORM\JoinTable(name="chill_calendar.calendar_to_invites")
-     * @Serializer\Groups({"read"})
+     * @Serializer\Groups({"read", "docgen:read"})
      */
     private Collection $invites;
 
     /**
      * @ORM\ManyToOne(targetEntity="Chill\MainBundle\Entity\Location")
-     * @Serializer\Groups({"read"})
+     * @Serializer\Groups({"read", "docgen:read"})
      * @Assert\NotNull(message="calendar.A location is required")
      */
     private ?Location $location = null;
 
     /**
      * @ORM\ManyToOne(targetEntity="Chill\MainBundle\Entity\User")
-     * @Serializer\Groups({"calendar:read", "read", "calendar:light"})
+     * @Serializer\Groups({"calendar:read", "read", "calendar:light", "docgen:read"})
      * @Serializer\Context(normalizationContext={"read"}, groups={"calendar:light"})
      * @Assert\NotNull(message="calendar.A main user is mandatory")
      */
@@ -158,7 +161,7 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
     /**
      * @ORM\ManyToMany(targetEntity="Chill\PersonBundle\Entity\Person", inversedBy="calendars")
      * @ORM\JoinTable(name="chill_calendar.calendar_to_persons")
-     * @Serializer\Groups({"calendar:read", "read", "calendar:light"})
+     * @Serializer\Groups({"calendar:read", "read", "calendar:light", "docgen:read"})
      * @Serializer\Context(normalizationContext={"read"}, groups={"calendar:light"})
      * @Assert\Count(min=1, minMessage="calendar.At least {{ limit }} person is required.")
      */
@@ -173,13 +176,14 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
     /**
      * @ORM\ManyToMany(targetEntity="Chill\ThirdPartyBundle\Entity\ThirdParty")
      * @ORM\JoinTable(name="chill_calendar.calendar_to_thirdparties")
-     * @Serializer\Groups({"calendar:read", "read", "calendar:light"})
+     * @Serializer\Groups({"calendar:read", "read", "calendar:light", "docgen:read"})
      * @Serializer\Context(normalizationContext={"read"}, groups={"calendar:light"})
      */
     private Collection $professionals;
 
     /**
      * @ORM\Column(type="boolean", nullable=true)
+     * @Serializer\Groups({"docgen:read"})
      */
     private ?bool $sendSMS = false;
 
@@ -190,7 +194,7 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
 
     /**
      * @ORM\Column(type="datetime_immutable", nullable=false)
-     * @Serializer\Groups({"calendar:read", "read", "calendar:light"})
+     * @Serializer\Groups({"calendar:read", "read", "calendar:light", "docgen:read"})
      * @Serializer\Context(normalizationContext={"read"}, groups={"calendar:light"})
      * @Assert\NotNull(message="calendar.A start date is required")
      */
@@ -205,6 +209,7 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
 
     /**
      * @ORM\Column(type="boolean", nullable=true)
+     * @Serializer\Groups({"docgen:read"})
      */
     private ?bool $urgent = false;
 
@@ -282,6 +287,9 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
         return $this->comment;
     }
 
+    /**
+     * @Serializer\Groups({"docgen:read"})
+     */
     public function getDuration(): ?DateInterval
     {
         if ($this->getStartDate() === null || $this->getEndDate() === null) {
diff --git a/src/Bundle/ChillCalendarBundle/Tests/Serializer/Normalizer/CalendarNormalizerTest.php b/src/Bundle/ChillCalendarBundle/Tests/Serializer/Normalizer/CalendarNormalizerTest.php
new file mode 100644
index 000000000..2a0975206
--- /dev/null
+++ b/src/Bundle/ChillCalendarBundle/Tests/Serializer/Normalizer/CalendarNormalizerTest.php
@@ -0,0 +1,109 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * Chill is a software for social workers
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Chill\CalendarBundle\Tests\Serializer\Normalizer;
+
+use Chill\CalendarBundle\Entity\Calendar;
+use Chill\MainBundle\Entity\Embeddable\CommentEmbeddable;
+use Chill\MainBundle\Entity\User;
+use Chill\PersonBundle\Entity\Person;
+use Chill\ThirdPartyBundle\Entity\ThirdParty;
+use DateTimeImmutable;
+use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
+use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
+
+/**
+ * @internal
+ * @coversNothing
+ */
+final class CalendarNormalizerTest extends KernelTestCase
+{
+    private NormalizerInterface $normalizer;
+
+    protected function setUp(): void
+    {
+        self::bootKernel();
+
+        $this->normalizer = self::$container->get(NormalizerInterface::class);
+    }
+
+    public function testNormalizationCalendar()
+    {
+        $calendar = (new Calendar())
+            ->setComment(
+                $comment = new CommentEmbeddable()
+            )
+            ->setStartDate(DateTimeImmutable::createFromFormat(DateTimeImmutable::ATOM, '2020-10-15T15:00:00+0000'))
+            ->setEndDate(DateTimeImmutable::createFromFormat(DateTimeImmutable::ATOM, '2020-15-15T15:30:00+0000'))
+            ->addPerson(new Person())
+            ->addPerson(new Person())
+            ->addUser(new User())
+            ->addProfessional(new ThirdParty());
+
+        $expected = [
+            'type' => 'chill_calendar_calendar',
+            'isNull' => false,
+            'urgent' => false,
+            'sendSMS' => false,
+        ];
+
+        $actual = $this->normalizer->normalize(
+            $calendar,
+            'docgen',
+            ['groups' => ['docgen:read'], 'docgen:expects' => Calendar::class]
+        );
+
+        // we first check for the known key/value...
+        foreach ($expected as $key => $value) {
+            $this->assertArrayHasKey($key, $actual);
+            $this->assertEquals($value, $actual[$key]);
+        }
+
+        // ... and then check for some other values
+        $this->assertArrayHasKey('persons', $actual);
+        $this->assertIsArray($actual['persons']);
+        $this->assertArrayHasKey('invites', $actual);
+        $this->assertIsArray($actual['invites']);
+        $this->assertArrayHasKey('startDate', $actual);
+        $this->assertIsArray($actual['startDate']);
+        $this->assertArrayHasKey('endDate', $actual);
+        $this->assertIsArray($actual['endDate']);
+        $this->assertArrayHasKey('professionals', $actual);
+        $this->assertIsArray($actual['professionals']);
+        $this->assertArrayHasKey('location', $actual);
+        $this->assertIsArray($actual['location']);
+        $this->assertArrayHasKey('mainUser', $actual);
+        $this->assertIsArray($actual['mainUser']);
+        $this->assertArrayHasKey('comment', $actual);
+        $this->assertIsArray($actual['comment']);
+        $this->assertArrayHasKey('duration', $actual);
+        $this->assertIsArray($actual['duration']);
+    }
+
+    public function testNormalizationOnNullHasSameKeys()
+    {
+        $calendar = new Calendar();
+
+        $notNullCalendar = $this->normalizer->normalize(
+            $calendar,
+            'docgen',
+            ['groups' => ['docgen:read'], 'docgen:expects' => Calendar::class]
+        );
+
+        $isNullCalendar = $this->normalizer->normalize(
+            null,
+            'docgen',
+            ['groups' => ['docgen:read'], 'docgen:expects' => Calendar::class]
+        );
+
+        $this->assertEqualsCanonicalizing(array_keys($notNullCalendar), array_keys($isNullCalendar));
+    }
+}