diff --git a/src/Bundle/ChillMainBundle/Controller/UserGroupApiController.php b/src/Bundle/ChillMainBundle/Controller/UserGroupApiController.php
new file mode 100644
index 000000000..602b84ec5
--- /dev/null
+++ b/src/Bundle/ChillMainBundle/Controller/UserGroupApiController.php
@@ -0,0 +1,16 @@
+<?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\MainBundle\Controller;
+
+use Chill\MainBundle\CRUD\Controller\ApiController;
+
+class UserGroupApiController extends ApiController {}
diff --git a/src/Bundle/ChillMainBundle/DataFixtures/ORM/LoadUserGroup.php b/src/Bundle/ChillMainBundle/DataFixtures/ORM/LoadUserGroup.php
new file mode 100644
index 000000000..614a83515
--- /dev/null
+++ b/src/Bundle/ChillMainBundle/DataFixtures/ORM/LoadUserGroup.php
@@ -0,0 +1,68 @@
+<?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\MainBundle\DataFixtures\ORM;
+
+use Chill\MainBundle\Entity\User;
+use Chill\MainBundle\Entity\UserGroup;
+use Doctrine\Bundle\FixturesBundle\Fixture;
+use Doctrine\Bundle\FixturesBundle\FixtureGroupInterface;
+use Doctrine\Persistence\ObjectManager;
+
+class LoadUserGroup extends Fixture implements FixtureGroupInterface
+{
+    public static function getGroups(): array
+    {
+        return ['user-group'];
+    }
+
+    public function load(ObjectManager $manager)
+    {
+        $centerASocial = $manager->getRepository(User::class)->findOneBy(['username' => 'center a_social']);
+        $centerBSocial = $manager->getRepository(User::class)->findOneBy(['username' => 'center b_social']);
+        $multiCenter = $manager->getRepository(User::class)->findOneBy(['username' => 'multi_center']);
+        $administrativeA = $manager->getRepository(User::class)->findOneBy(['username' => 'center a_administrative']);
+        $administrativeB = $manager->getRepository(User::class)->findOneBy(['username' => 'center b_administrative']);
+
+        $level1 = $this->generateLevelGroup('Niveau 1', '#eec84aff', '#000000ff', 'level');
+        $level1->addUser($centerASocial)->addUser($centerBSocial);
+        $manager->persist($level1);
+
+        $level2 = $this->generateLevelGroup('Niveau 2', ' #e2793dff', '#000000ff', 'level');
+        $level2->addUser($multiCenter);
+        $manager->persist($level2);
+
+        $level3 = $this->generateLevelGroup('Niveau 3', ' #df4949ff', '#000000ff', 'level');
+        $level3->addUser($multiCenter);
+        $manager->persist($level3);
+
+        $tss = $this->generateLevelGroup('Travailleur sociaux', '#43b29dff', '#000000ff', '');
+        $tss->addUser($multiCenter)->addUser($centerASocial)->addUser($centerBSocial);
+        $manager->persist($tss);
+        $admins = $this->generateLevelGroup('Administratif', '#334d5cff', '#000000ff', '');
+        $admins->addUser($administrativeA)->addUser($administrativeB);
+        $manager->persist($admins);
+
+        $manager->flush();
+    }
+
+    private function generateLevelGroup(string $title, string $backgroundColor, string $foregroundColor, string $excludeKey): UserGroup
+    {
+        $userGroup = new UserGroup();
+
+        return $userGroup
+            ->setLabel(['fr' => $title])
+            ->setBackgroundColor($backgroundColor)
+            ->setForegroundColor($foregroundColor)
+            ->setExcludeKey($excludeKey)
+        ;
+    }
+}
diff --git a/src/Bundle/ChillMainBundle/DependencyInjection/ChillMainExtension.php b/src/Bundle/ChillMainBundle/DependencyInjection/ChillMainExtension.php
index 4dde2076c..3170cadee 100644
--- a/src/Bundle/ChillMainBundle/DependencyInjection/ChillMainExtension.php
+++ b/src/Bundle/ChillMainBundle/DependencyInjection/ChillMainExtension.php
@@ -24,6 +24,7 @@ use Chill\MainBundle\Controller\LocationTypeController;
 use Chill\MainBundle\Controller\NewsItemController;
 use Chill\MainBundle\Controller\RegroupmentController;
 use Chill\MainBundle\Controller\UserController;
+use Chill\MainBundle\Controller\UserGroupApiController;
 use Chill\MainBundle\Controller\UserJobApiController;
 use Chill\MainBundle\Controller\UserJobController;
 use Chill\MainBundle\DependencyInjection\Widget\Factory\WidgetFactoryInterface;
@@ -59,6 +60,7 @@ use Chill\MainBundle\Entity\LocationType;
 use Chill\MainBundle\Entity\NewsItem;
 use Chill\MainBundle\Entity\Regroupment;
 use Chill\MainBundle\Entity\User;
+use Chill\MainBundle\Entity\UserGroup;
 use Chill\MainBundle\Entity\UserJob;
 use Chill\MainBundle\Form\CenterType;
 use Chill\MainBundle\Form\CivilityType;
@@ -803,6 +805,21 @@ class ChillMainExtension extends Extension implements
                         ],
                     ],
                 ],
+                [
+                    'class' => UserGroup::class,
+                    'controller' => UserGroupApiController::class,
+                    'name' => 'user-group',
+                    'base_path' => '/api/1.0/main/user-group',
+                    'base_role' => 'ROLE_USER',
+                    'actions' => [
+                        '_index' => [
+                            'methods' => [
+                                Request::METHOD_GET => true,
+                                Request::METHOD_HEAD => true,
+                            ],
+                        ],
+                    ],
+                ],
             ],
         ]);
     }
diff --git a/src/Bundle/ChillMainBundle/Entity/UserGroup.php b/src/Bundle/ChillMainBundle/Entity/UserGroup.php
index 3bd9870a6..470a21a70 100644
--- a/src/Bundle/ChillMainBundle/Entity/UserGroup.php
+++ b/src/Bundle/ChillMainBundle/Entity/UserGroup.php
@@ -14,17 +14,21 @@ namespace Chill\MainBundle\Entity;
 use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Collection;
 use Doctrine\ORM\Mapping as ORM;
+use Symfony\Component\Serializer\Annotation as Serializer;
 
 #[ORM\Entity]
 #[ORM\Table(name: 'chill_main_user_group')]
+#[Serializer\DiscriminatorMap(typeProperty: 'type', mapping: ['user_group' => UserGroup::class])]
 class UserGroup
 {
     #[ORM\Id]
     #[ORM\GeneratedValue]
     #[ORM\Column(type: \Doctrine\DBAL\Types\Types::INTEGER, nullable: false)]
+    #[Serializer\Groups(['read'])]
     private ?int $id = null;
 
     #[ORM\Column(type: \Doctrine\DBAL\Types\Types::JSON, nullable: false, options: ['default' => '[]'])]
+    #[Serializer\Groups(['read'])]
     private array $label = [];
 
     /**
@@ -34,6 +38,24 @@ class UserGroup
     #[ORM\JoinTable(name: 'chill_main_user_group_user')]
     private Collection $users;
 
+    #[ORM\Column(type: 'text', nullable: false, options: ['default' => '#ffffffff'])]
+    #[Serializer\Groups(['read'])]
+    private string $backgroundColor = '#ffffffff';
+
+    #[ORM\Column(type: 'text', nullable: false, options: ['default' => '#000000ff'])]
+    #[Serializer\Groups(['read'])]
+    private string $foregroundColor = '#000000ff';
+
+    /**
+     * Groups with same exclude key are mutually exclusive: adding one in a many-to-one relationship
+     * will exclude others.
+     *
+     * An empty string means "no exclusion"
+     */
+    #[ORM\Column(type: 'text', nullable: false, options: ['default' => ''])]
+    #[Serializer\Groups(['read'])]
+    private string $excludeKey = '';
+
     public function __construct()
     {
         $this->users = new ArrayCollection();
@@ -71,4 +93,47 @@ class UserGroup
     {
         return $this->users;
     }
+
+    public function getForegroundColor(): string
+    {
+        return $this->foregroundColor;
+    }
+
+    public function getExcludeKey(): string
+    {
+        return $this->excludeKey;
+    }
+
+    public function getBackgroundColor(): string
+    {
+        return $this->backgroundColor;
+    }
+
+    public function setForegroundColor(string $foregroundColor): self
+    {
+        $this->foregroundColor = $foregroundColor;
+
+        return $this;
+    }
+
+    public function setBackgroundColor(string $backgroundColor): self
+    {
+        $this->backgroundColor = $backgroundColor;
+
+        return $this;
+    }
+
+    public function setExcludeKey(string $excludeKey): self
+    {
+        $this->excludeKey = $excludeKey;
+
+        return $this;
+    }
+
+    public function setLabel(array $label): self
+    {
+        $this->label = $label;
+
+        return $this;
+    }
 }
diff --git a/src/Bundle/ChillMainBundle/Resources/public/types.ts b/src/Bundle/ChillMainBundle/Resources/public/types.ts
index 2e33b8248..840a0e939 100644
--- a/src/Bundle/ChillMainBundle/Resources/public/types.ts
+++ b/src/Bundle/ChillMainBundle/Resources/public/types.ts
@@ -42,6 +42,15 @@ export interface User {
   // todo: mainCenter; mainJob; etc..
 }
 
+export interface UserGroup {
+    type: "chill_main_user_group",
+    id: number,
+    label: TranslatableString,
+    backgroundColor: string,
+    foregroundColor: string,
+    excludeKey: string,
+}
+
 export interface UserAssociatedInterface {
   type: "user";
   id: number;
diff --git a/src/Bundle/ChillMainBundle/Tests/Validation/Validator/UserGroupDoNotExcludeTest.php b/src/Bundle/ChillMainBundle/Tests/Validation/Validator/UserGroupDoNotExcludeTest.php
new file mode 100644
index 000000000..d6d1c9887
--- /dev/null
+++ b/src/Bundle/ChillMainBundle/Tests/Validation/Validator/UserGroupDoNotExcludeTest.php
@@ -0,0 +1,91 @@
+<?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\MainBundle\Tests\Validation\Validator;
+
+use Chill\MainBundle\Entity\User;
+use Chill\MainBundle\Entity\UserGroup;
+use Chill\MainBundle\Templating\TranslatableStringHelperInterface;
+use Chill\MainBundle\Validation\Validator\UserGroupDoNotExclude;
+use Symfony\Component\Validator\Test\ConstraintValidatorTestCase;
+
+/**
+ * @internal
+ *
+ * @coversNothing
+ */
+class UserGroupDoNotExcludeTest extends ConstraintValidatorTestCase
+{
+    protected function createValidator()
+    {
+        return new UserGroupDoNotExclude(
+            new class () implements TranslatableStringHelperInterface {
+                public function localize(array $translatableStrings): ?string
+                {
+                    return $translatableStrings['fr'];
+                }
+            }
+        );
+    }
+
+    public function testEmptyArrayIsValid(): void
+    {
+        $this->validator->validate([], new \Chill\MainBundle\Validation\Constraint\UserGroupDoNotExclude());
+
+        $this->assertNoViolation();
+    }
+
+    public function testMixedUserGroupAndUsersIsValid(): void
+    {
+        $this->validator->validate(
+            [new User(), new UserGroup()],
+            new \Chill\MainBundle\Validation\Constraint\UserGroupDoNotExclude()
+        );
+
+        $this->assertNoViolation();
+    }
+
+    public function testDifferentExcludeKeysIsValid(): void
+    {
+        $this->validator->validate(
+            [(new UserGroup())->setExcludeKey('A'), (new UserGroup())->setExcludeKey('B')],
+            new \Chill\MainBundle\Validation\Constraint\UserGroupDoNotExclude()
+        );
+
+        $this->assertNoViolation();
+    }
+
+    public function testMultipleGroupsWithEmptyExcludeKeyIsValid(): void
+    {
+        $this->validator->validate(
+            [(new UserGroup())->setExcludeKey(''), (new UserGroup())->setExcludeKey('')],
+            new \Chill\MainBundle\Validation\Constraint\UserGroupDoNotExclude()
+        );
+
+        $this->assertNoViolation();
+    }
+
+    public function testSameExclusionKeyWillRaiseError(): void
+    {
+        $this->validator->validate(
+            [
+                (new UserGroup())->setExcludeKey('A')->setLabel(['fr' => 'Group 1']),
+                (new UserGroup())->setExcludeKey('A')->setLabel(['fr' => 'Group 2']),
+            ],
+            new \Chill\MainBundle\Validation\Constraint\UserGroupDoNotExclude()
+        );
+
+        $this->buildViolation('The groups {{ excluded_groups }} do exclude themselves. Please choose one between them')
+            ->setParameter('excluded_groups', 'Group 1, Group 2')
+            ->setCode('e16c8226-0090-11ef-8560-f7239594db09')
+            ->assertRaised();
+    }
+}
diff --git a/src/Bundle/ChillMainBundle/Validation/Constraint/UserGroupDoNotExclude.php b/src/Bundle/ChillMainBundle/Validation/Constraint/UserGroupDoNotExclude.php
new file mode 100644
index 000000000..5ec688e5b
--- /dev/null
+++ b/src/Bundle/ChillMainBundle/Validation/Constraint/UserGroupDoNotExclude.php
@@ -0,0 +1,31 @@
+<?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\MainBundle\Validation\Constraint;
+
+use Symfony\Component\Validator\Constraint;
+
+#[\Attribute(\Attribute::TARGET_PROPERTY)]
+class UserGroupDoNotExclude extends Constraint
+{
+    public string $message = 'The groups {{ excluded_groups }} do exclude themselves. Please choose one between them';
+    public string $code = 'e16c8226-0090-11ef-8560-f7239594db09';
+
+    public function getTargets()
+    {
+        return [self::PROPERTY_CONSTRAINT];
+    }
+
+    public function validatedBy()
+    {
+        return \Chill\MainBundle\Validation\Validator\UserGroupDoNotExclude::class;
+    }
+}
diff --git a/src/Bundle/ChillMainBundle/Validation/Validator/UserGroupDoNotExclude.php b/src/Bundle/ChillMainBundle/Validation/Validator/UserGroupDoNotExclude.php
new file mode 100644
index 000000000..9bd7167c7
--- /dev/null
+++ b/src/Bundle/ChillMainBundle/Validation/Validator/UserGroupDoNotExclude.php
@@ -0,0 +1,69 @@
+<?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\MainBundle\Validation\Validator;
+
+use Chill\MainBundle\Entity\UserGroup;
+use Chill\MainBundle\Templating\TranslatableStringHelperInterface;
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+use Symfony\Component\Validator\Exception\UnexpectedTypeException;
+use Symfony\Component\Validator\Exception\UnexpectedValueException;
+
+final class UserGroupDoNotExclude extends ConstraintValidator
+{
+    public function __construct(private readonly TranslatableStringHelperInterface $translatableStringHelper) {}
+
+    public function validate($value, Constraint $constraint)
+    {
+        if (!$constraint instanceof \Chill\MainBundle\Validation\Constraint\UserGroupDoNotExclude) {
+            throw new UnexpectedTypeException($constraint, UserGroupDoNotExclude::class);
+        }
+
+        if (null === $value) {
+            return;
+        }
+
+        if (!is_iterable($value)) {
+            throw new UnexpectedValueException($value, 'iterable');
+        }
+
+        $groups = [];
+
+        foreach ($value as $gr) {
+            if ($gr instanceof UserGroup) {
+                $groups[$gr->getExcludeKey()][] = $gr;
+            }
+        }
+
+        foreach ($groups as $excludeKey => $groupByKey) {
+            if ('' === $excludeKey) {
+                continue;
+            }
+
+            if (1 < count($groupByKey)) {
+                $excludedGroups = implode(
+                    ', ',
+                    array_map(
+                        fn (UserGroup $group) => $this->translatableStringHelper->localize($group->getLabel()),
+                        $groupByKey
+                    )
+                );
+
+                $this->context
+                    ->buildViolation($constraint->message)
+                    ->setCode($constraint->code)
+                    ->setParameters(['excluded_groups' => $excludedGroups])
+                    ->addViolation();
+            }
+        }
+    }
+}
diff --git a/src/Bundle/ChillMainBundle/chill.api.specs.yaml b/src/Bundle/ChillMainBundle/chill.api.specs.yaml
index f37ee723d..fec36312d 100644
--- a/src/Bundle/ChillMainBundle/chill.api.specs.yaml
+++ b/src/Bundle/ChillMainBundle/chill.api.specs.yaml
@@ -908,3 +908,19 @@ paths:
                                     $ref: '#/components/schemas/NewsItem'
                 403:
                     description: "Unauthorized"
+    /1.0/main/user-group.json:
+        get:
+            tags:
+                - user-group
+            summary: Return a list of users-groups
+            responses:
+                200:
+                    description: "ok"
+                    content:
+                        application/json:
+                            schema:
+                                type: array
+                                items:
+                                    $ref: '#/components/schemas/NewsItem'
+                403:
+                    description: "Unauthorized"
diff --git a/src/Bundle/ChillMainBundle/migrations/Version20240422091752.php b/src/Bundle/ChillMainBundle/migrations/Version20240422091752.php
new file mode 100644
index 000000000..960b3cc79
--- /dev/null
+++ b/src/Bundle/ChillMainBundle/migrations/Version20240422091752.php
@@ -0,0 +1,41 @@
+<?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\Migrations\Main;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+final class Version20240422091752 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Add colors and exclude string to user groups';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE chill_main_user_group ADD backgroundColor TEXT DEFAULT \'#ffffffff\' NOT NULL');
+        $this->addSql('ALTER TABLE chill_main_user_group ADD foregroundColor TEXT DEFAULT \'#000000ff\' NOT NULL');
+        $this->addSql('ALTER TABLE chill_main_user_group ADD excludeKey TEXT DEFAULT \'\' NOT NULL');
+        $this->addSql('ALTER INDEX idx_1e07f044d2112630 RENAME TO IDX_738BC82BD2112630');
+        $this->addSql('ALTER INDEX idx_1e07f044a76ed395 RENAME TO IDX_738BC82BA76ED395');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE chill_main_user_group DROP backgroundColor');
+        $this->addSql('ALTER TABLE chill_main_user_group DROP foregroundColor');
+        $this->addSql('ALTER TABLE chill_main_user_group DROP excludeKey');
+        $this->addSql('ALTER INDEX idx_738bc82bd2112630 RENAME TO idx_1e07f044d2112630');
+        $this->addSql('ALTER INDEX idx_738bc82ba76ed395 RENAME TO idx_1e07f044a76ed395');
+    }
+}
diff --git a/src/Bundle/ChillTicketBundle/chill.api.specs.yaml b/src/Bundle/ChillTicketBundle/chill.api.specs.yaml
index ce53732ff..86049cc24 100644
--- a/src/Bundle/ChillTicketBundle/chill.api.specs.yaml
+++ b/src/Bundle/ChillTicketBundle/chill.api.specs.yaml
@@ -64,3 +64,32 @@ paths:
                     description: "ACCEPTED"
                 422:
                     description: "UNPROCESSABLE ENTITY"
+
+    /1.0/ticket/{id}/comment/add:
+        post:
+            tags:
+                - ticket
+            summary: Add a comment to an existing ticket
+            parameters:
+                -   name: id
+                    in: path
+                    required: true
+                    description: The ticket id
+                    schema:
+                        type: integer
+                        format: integer
+                        minimum: 1
+            requestBody:
+                required: true
+                content:
+                    application/json:
+                        schema:
+                            type: object
+                            properties:
+                                content:
+                                    type: string
+            responses:
+                201:
+                    description: "ACCEPTED"
+                422:
+                    description: "UNPROCESSABLE ENTITY"
diff --git a/src/Bundle/ChillTicketBundle/src/Action/Ticket/AddCommentCommand.php b/src/Bundle/ChillTicketBundle/src/Action/Ticket/AddCommentCommand.php
new file mode 100644
index 000000000..1c009cfc8
--- /dev/null
+++ b/src/Bundle/ChillTicketBundle/src/Action/Ticket/AddCommentCommand.php
@@ -0,0 +1,25 @@
+<?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\TicketBundle\Action\Ticket;
+
+use Symfony\Component\Validator\Constraints as Assert;
+use Symfony\Component\Serializer\Annotation as Serializer;
+
+final readonly class AddCommentCommand
+{
+    public function __construct(
+        #[Assert\NotBlank()]
+        #[Assert\NotNull]
+        #[Serializer\Groups(['write'])]
+        public ?string $content = null,
+    ) {}
+}
diff --git a/src/Bundle/ChillTicketBundle/src/Action/Ticket/Handler/AddCommentCommandHandler.php b/src/Bundle/ChillTicketBundle/src/Action/Ticket/Handler/AddCommentCommandHandler.php
new file mode 100644
index 000000000..66c972c3d
--- /dev/null
+++ b/src/Bundle/ChillTicketBundle/src/Action/Ticket/Handler/AddCommentCommandHandler.php
@@ -0,0 +1,31 @@
+<?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\TicketBundle\Action\Ticket\Handler;
+
+use Chill\TicketBundle\Action\Ticket\AddCommentCommand;
+use Chill\TicketBundle\Entity\Comment;
+use Chill\TicketBundle\Entity\Ticket;
+use Doctrine\ORM\EntityManagerInterface;
+
+final readonly class AddCommentCommandHandler
+{
+    public function __construct(
+        private EntityManagerInterface $entityManager,
+    ) {}
+
+    public function handle(Ticket $ticket, AddCommentCommand $command): void
+    {
+        $comment = new Comment($command->content, $ticket);
+
+        $this->entityManager->persist($comment);
+    }
+}
diff --git a/src/Bundle/ChillTicketBundle/src/Controller/AddCommentController.php b/src/Bundle/ChillTicketBundle/src/Controller/AddCommentController.php
new file mode 100644
index 000000000..157e69698
--- /dev/null
+++ b/src/Bundle/ChillTicketBundle/src/Controller/AddCommentController.php
@@ -0,0 +1,68 @@
+<?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\TicketBundle\Controller;
+
+use Chill\TicketBundle\Action\Ticket\AddCommentCommand;
+use Chill\TicketBundle\Action\Ticket\Handler\AddCommentCommandHandler;
+use Chill\TicketBundle\Entity\Ticket;
+use Doctrine\ORM\EntityManagerInterface;
+use Symfony\Component\HttpFoundation\JsonResponse;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
+use Symfony\Component\Routing\Annotation\Route;
+use Symfony\Component\Security\Core\Security;
+use Symfony\Component\Serializer\SerializerInterface;
+use Symfony\Component\Validator\Validator\ValidatorInterface;
+
+final readonly class AddCommentController
+{
+    public function __construct(
+        private Security $security,
+        private SerializerInterface $serializer,
+        private ValidatorInterface $validator,
+        private AddCommentCommandHandler $addCommentCommandHandler,
+        private EntityManagerInterface $entityManager,
+    ) {}
+
+    #[Route('/api/1.0/ticket/{id}/comment/add', name: 'chill_ticket_comment_add', methods: ['POST'])]
+    public function __invoke(Ticket $ticket, Request $request): Response
+    {
+        if (!$this->security->isGranted('ROLE_USER')) {
+            throw new AccessDeniedHttpException('Only user can add ticket comments.');
+        }
+
+        $command = $this->serializer->deserialize($request->getContent(), AddCommentCommand::class, 'json', ['groups' => 'write']);
+
+        $errors = $this->validator->validate($command);
+
+        if (count($errors) > 0) {
+            return new JsonResponse(
+                $this->serializer->serialize($errors, 'json'),
+                Response::HTTP_UNPROCESSABLE_ENTITY,
+                [],
+                true
+            );
+        }
+
+        $this->addCommentCommandHandler->handle($ticket, $command);
+
+        $this->entityManager->flush();
+
+        return new JsonResponse(
+            $this->serializer->serialize($ticket, 'json', ['groups' => 'read']),
+            Response::HTTP_CREATED,
+            [],
+            true
+        );
+    }
+}
diff --git a/src/Bundle/ChillTicketBundle/src/Controller/ReplaceMotiveController.php b/src/Bundle/ChillTicketBundle/src/Controller/ReplaceMotiveController.php
index d6f1acf94..8af2773e8 100644
--- a/src/Bundle/ChillTicketBundle/src/Controller/ReplaceMotiveController.php
+++ b/src/Bundle/ChillTicketBundle/src/Controller/ReplaceMotiveController.php
@@ -59,6 +59,11 @@ final readonly class ReplaceMotiveController
 
         $this->entityManager->flush();
 
-        return new JsonResponse(null, Response::HTTP_CREATED);
+        return new JsonResponse(
+            $this->serializer->serialize($ticket, 'json', ['groups' => 'read']),
+            Response::HTTP_CREATED,
+            [],
+            true
+        );
     }
 }
diff --git a/src/Bundle/ChillTicketBundle/src/Entity/Comment.php b/src/Bundle/ChillTicketBundle/src/Entity/Comment.php
index d62e6d8b4..8e11ff489 100644
--- a/src/Bundle/ChillTicketBundle/src/Entity/Comment.php
+++ b/src/Bundle/ChillTicketBundle/src/Entity/Comment.php
@@ -17,9 +17,11 @@ use Chill\MainBundle\Doctrine\Model\TrackUpdateInterface;
 use Chill\MainBundle\Doctrine\Model\TrackUpdateTrait;
 use Doctrine\ORM\Mapping as ORM;
 use Doctrine\ORM\Mapping\JoinColumn;
+use Symfony\Component\Serializer\Annotation as Serializer;
 
 #[ORM\Entity()]
 #[ORM\Table(name: 'comment', schema: 'chill_ticket')]
+#[Serializer\DiscriminatorMap(typeProperty: 'type', mapping: ['ticket_comment' => Comment::class])]
 class Comment implements TrackCreationInterface, TrackUpdateInterface
 {
     use TrackCreationTrait;
@@ -28,15 +30,19 @@ class Comment implements TrackCreationInterface, TrackUpdateInterface
     #[ORM\Id]
     #[ORM\Column(type: \Doctrine\DBAL\Types\Types::INTEGER, nullable: false)]
     #[ORM\GeneratedValue(strategy: 'AUTO')]
+    #[Serializer\Groups(['read'])]
     private ?int $id = null;
 
     public function __construct(
+        #[ORM\Column(type: \Doctrine\DBAL\Types\Types::TEXT, nullable: false, options: ['default' => ''])]
+        #[Serializer\Groups(['read'])]
+        private string $content,
         #[ORM\ManyToOne(targetEntity: Ticket::class, inversedBy: 'comments')]
         #[JoinColumn(nullable: false)]
         private Ticket $ticket,
-        #[ORM\Column(type: \Doctrine\DBAL\Types\Types::TEXT, nullable: false, options: ['default' => ''])]
-        private string $content = ''
-    ) {}
+    ) {
+        $ticket->addComment($this);
+    }
 
     public function getId(): ?int
     {
diff --git a/src/Bundle/ChillTicketBundle/src/Entity/Ticket.php b/src/Bundle/ChillTicketBundle/src/Entity/Ticket.php
index de369379b..cd49d7377 100644
--- a/src/Bundle/ChillTicketBundle/src/Entity/Ticket.php
+++ b/src/Bundle/ChillTicketBundle/src/Entity/Ticket.php
@@ -104,16 +104,27 @@ class Ticket implements TrackCreationInterface, TrackUpdateInterface
             ->getValues();
     }
 
+    /**
+     * @internal use @see{Comment::__construct} instead
+     */
+    public function addComment(Comment $comment): void
+    {
+        $this->comments->add($comment);
+    }
+
     /**
      * Add a PersonHistory.
      *
-     * This method should not be used, use @see{PersonHistory::__construct()} insted.
+     * @internal use @see{PersonHistory::__construct} instead
      */
     public function addPersonHistory(PersonHistory $personHistory): void
     {
         $this->personHistories->add($personHistory);
     }
 
+    /**
+     * @internal use @see{MotiveHistory::__construct} instead
+     */
     public function addMotiveHistory(MotiveHistory $motiveHistory): void
     {
         $this->motiveHistories->add($motiveHistory);
diff --git a/src/Bundle/ChillTicketBundle/src/Resources/public/types.ts b/src/Bundle/ChillTicketBundle/src/Resources/public/types.ts
index b0c6a37df..2df53da99 100644
--- a/src/Bundle/ChillTicketBundle/src/Resources/public/types.ts
+++ b/src/Bundle/ChillTicketBundle/src/Resources/public/types.ts
@@ -36,10 +36,21 @@ interface MotiveHistory {
     createdAt: DateTime|null,
 }
 
+interface Comment {
+    type: "ticket_comment",
+    id: number,
+    content: string,
+    createdBy: User|null,
+    createdAt: DateTime|null,
+    updatedBy: User|null,
+    updatedAt: DateTime|null,
+}
+
 interface AddPersonEvent extends TicketHistory<"add_person", PersonHistory> {};
+interface AddCommentEvent extends TicketHistory<"add_comment", Comment> {};
 interface SetMotiveEvent extends TicketHistory<"set_motive", MotiveHistory> {};
 
-type TicketHistoryLine = AddPersonEvent | SetMotiveEvent;
+type TicketHistoryLine = AddPersonEvent | AddCommentEvent | SetMotiveEvent;
 
 export interface Ticket {
     type: "ticket_ticket"
diff --git a/src/Bundle/ChillTicketBundle/src/Serializer/Normalizer/TicketNormalizer.php b/src/Bundle/ChillTicketBundle/src/Serializer/Normalizer/TicketNormalizer.php
index c69ac5a7f..c68ab34ef 100644
--- a/src/Bundle/ChillTicketBundle/src/Serializer/Normalizer/TicketNormalizer.php
+++ b/src/Bundle/ChillTicketBundle/src/Serializer/Normalizer/TicketNormalizer.php
@@ -11,6 +11,7 @@ declare(strict_types=1);
 
 namespace Chill\TicketBundle\Serializer\Normalizer;
 
+use Chill\TicketBundle\Entity\Comment;
 use Chill\TicketBundle\Entity\MotiveHistory;
 use Chill\TicketBundle\Entity\PersonHistory;
 use Chill\TicketBundle\Entity\Ticket;
@@ -69,6 +70,15 @@ final class TicketNormalizer implements NormalizerInterface, NormalizerAwareInte
                 ],
                 $ticket->getPersonHistories()->toArray(),
             ),
+            ...array_map(
+                fn (Comment $comment) => [
+                    'event_type' => 'add_comment',
+                    'at' => $comment->getCreatedAt(),
+                    'by' => $comment->getCreatedBy(),
+                    'data' => $comment,
+                ],
+                $ticket->getComments()->toArray(),
+            ),
         ];
 
         usort(
diff --git a/src/Bundle/ChillTicketBundle/tests/Action/Ticket/Handler/AddCommentCommandHandlerTest.php b/src/Bundle/ChillTicketBundle/tests/Action/Ticket/Handler/AddCommentCommandHandlerTest.php
new file mode 100644
index 000000000..5ff18b436
--- /dev/null
+++ b/src/Bundle/ChillTicketBundle/tests/Action/Ticket/Handler/AddCommentCommandHandlerTest.php
@@ -0,0 +1,52 @@
+<?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\TicketBundle\Tests\Action\Ticket\Handler;
+
+use Chill\TicketBundle\Action\Ticket\AddCommentCommand;
+use Chill\TicketBundle\Action\Ticket\Handler\AddCommentCommandHandler;
+use Chill\TicketBundle\Entity\Comment;
+use Chill\TicketBundle\Entity\Ticket;
+use Doctrine\ORM\EntityManagerInterface;
+use PHPUnit\Framework\TestCase;
+use Prophecy\Argument;
+use Prophecy\PhpUnit\ProphecyTrait;
+
+/**
+ * @internal
+ *
+ * @coversNothing
+ */
+class AddCommentCommandHandlerTest extends TestCase
+{
+    use ProphecyTrait;
+
+    public function testAddComment(): void
+    {
+        $handler = $this->buildCommand();
+
+        $ticket = new Ticket();
+        $command = new AddCommentCommand(content: 'test');
+
+        $handler->handle($ticket, $command);
+
+        self::assertCount(1, $ticket->getComments());
+        self::assertEquals('test', $ticket->getComments()[0]->getContent());
+    }
+
+    private function buildCommand(): AddCommentCommandHandler
+    {
+        $entityManager = $this->prophesize(EntityManagerInterface::class);
+        $entityManager->persist(Argument::type(Comment::class))->shouldBeCalled();
+
+        return new AddCommentCommandHandler($entityManager->reveal());
+    }
+}
diff --git a/src/Bundle/ChillTicketBundle/tests/Controller/AddCommentControllerTest.php b/src/Bundle/ChillTicketBundle/tests/Controller/AddCommentControllerTest.php
new file mode 100644
index 000000000..2826c360d
--- /dev/null
+++ b/src/Bundle/ChillTicketBundle/tests/Controller/AddCommentControllerTest.php
@@ -0,0 +1,104 @@
+<?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\TicketBundle\Tests\Controller;
+
+use Chill\TicketBundle\Action\Ticket\Handler\AddCommentCommandHandler;
+use Chill\TicketBundle\Controller\AddCommentController;
+use Chill\TicketBundle\Entity\Comment;
+use Chill\TicketBundle\Entity\Ticket;
+use Doctrine\ORM\EntityManagerInterface;
+use Prophecy\Argument;
+use Prophecy\PhpUnit\ProphecyTrait;
+use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\Security\Core\Security;
+use Symfony\Component\Serializer\SerializerInterface;
+use Symfony\Component\Validator\Validator\ValidatorInterface;
+
+/**
+ * @internal
+ *
+ * @coversNothing
+ */
+class AddCommentControllerTest extends KernelTestCase
+{
+    use ProphecyTrait;
+
+    private SerializerInterface $serializer;
+    private ValidatorInterface $validator;
+
+    protected function setUp(): void
+    {
+        self::bootKernel();
+        $this->validator = self::getContainer()->get(ValidatorInterface::class);
+        $this->serializer = self::getContainer()->get(SerializerInterface::class);
+    }
+
+    public function testAddComment(): void
+    {
+        $controller = $this->buildController(willFlush: true);
+
+        $ticket = new Ticket();
+        $request = new Request(content: <<<'JSON'
+            {"content":  "test"}
+            JSON);
+
+        $response = $controller->__invoke($ticket, $request);
+
+        self::assertEquals(201, $response->getStatusCode());
+    }
+
+    public function testAddCommentWithBlankContent(): void
+    {
+        $controller = $this->buildController(willFlush: false);
+
+        $ticket = new Ticket();
+        $request = new Request(content: <<<'JSON'
+            {"content":  ""}
+            JSON);
+
+        $response = $controller->__invoke($ticket, $request);
+
+        self::assertEquals(422, $response->getStatusCode());
+
+        $request = new Request(content: <<<'JSON'
+            {"content":  null}
+            JSON);
+
+        $response = $controller->__invoke($ticket, $request);
+
+        self::assertEquals(422, $response->getStatusCode());
+    }
+
+    private function buildController(bool $willFlush): AddCommentController
+    {
+        $security = $this->prophesize(Security::class);
+        $security->isGranted('ROLE_USER')->willReturn(true);
+
+        $entityManager = $this->prophesize(EntityManagerInterface::class);
+
+        if ($willFlush) {
+            $entityManager->persist(Argument::type(Comment::class))->shouldBeCalled();
+            $entityManager->flush()->shouldBeCalled();
+        }
+
+        $commandHandler = new AddCommentCommandHandler($entityManager->reveal());
+
+        return new AddCommentController(
+            $security->reveal(),
+            $this->serializer,
+            $this->validator,
+            $commandHandler,
+            $entityManager->reveal(),
+        );
+    }
+}
diff --git a/src/Bundle/ChillTicketBundle/tests/Serializer/Normalizer/TicketNormalizerTest.php b/src/Bundle/ChillTicketBundle/tests/Serializer/Normalizer/TicketNormalizerTest.php
index e876341cd..447bebfbf 100644
--- a/src/Bundle/ChillTicketBundle/tests/Serializer/Normalizer/TicketNormalizerTest.php
+++ b/src/Bundle/ChillTicketBundle/tests/Serializer/Normalizer/TicketNormalizerTest.php
@@ -11,7 +11,9 @@ declare(strict_types=1);
 
 namespace Chill\TicketBundle\Tests\Serializer\Normalizer;
 
+use Chill\MainBundle\Entity\User;
 use Chill\PersonBundle\Entity\Person;
+use Chill\TicketBundle\Entity\Comment;
 use Chill\TicketBundle\Entity\Motive;
 use Chill\TicketBundle\Entity\MotiveHistory;
 use Chill\TicketBundle\Entity\PersonHistory;
@@ -93,11 +95,20 @@ class TicketNormalizerTest extends KernelTestCase
         // datetime
         $normalizer->normalize(Argument::type(\DateTimeImmutable::class), 'json', Argument::type('array'))
             ->will(function ($args) { return $args[0]->getTimestamp(); });
+        // user
+        $normalizer->normalize(Argument::type(User::class), 'json', Argument::type('array'))
+            ->willReturn(['user']);
+        // motive
         $normalizer->normalize(Argument::type(Motive::class), 'json', Argument::type('array'))->willReturn(['type' => 'motive', 'id' => 0]);
+        // person history
         $normalizer->normalize(Argument::type(PersonHistory::class), 'json', Argument::type('array'))
             ->willReturn(['personHistory']);
+        // motive history
         $normalizer->normalize(Argument::type(MotiveHistory::class), 'json', Argument::type('array'))
             ->willReturn(['motiveHistory']);
+        $normalizer->normalize(Argument::type(Comment::class), 'json', Argument::type('array'))
+            ->willReturn(['comment']);
+        // null values
         $normalizer->normalize(null, 'json', Argument::type('array'))->willReturn(null);
 
         $ticketNormalizer = new TicketNormalizer();
@@ -109,6 +120,7 @@ class TicketNormalizerTest extends KernelTestCase
     public static function provideTickets(): iterable
     {
         yield [
+            // this a nearly empty ticket
             new Ticket(),
             [
                 'type' => 'ticket_ticket',
@@ -122,10 +134,14 @@ class TicketNormalizerTest extends KernelTestCase
             ],
         ];
 
+        // ticket with more features
         $ticket = new Ticket();
         $ticket->setExternalRef('2134');
         $personHistory = new PersonHistory(new Person(), $ticket, new \DateTimeImmutable('2024-04-01T12:00:00'));
         $ticketHistory = new MotiveHistory(new Motive(), $ticket, new \DateTimeImmutable('2024-04-01T12:02:00'));
+        $comment = new Comment('blabla test', $ticket);
+        $comment->setCreatedAt(new \DateTimeImmutable('2024-04-01T12:04:00'));
+        $comment->setCreatedBy(new User());
 
         yield [
             $ticket,
@@ -137,7 +153,7 @@ class TicketNormalizerTest extends KernelTestCase
                 'currentAddressees' => [],
                 'currentInputs' => [],
                 'currentMotive' => ['type' => 'motive', 'id' => 0],
-                'history' => [['event_type' => 'add_person'], ['event_type' => 'set_motive']],
+                'history' => [['event_type' => 'add_person'], ['event_type' => 'set_motive'], ['event_type' => 'add_comment']],
             ],
         ];
     }