diff --git a/psalm-baseline.xml b/psalm-baseline.xml
index 7f8c7f4..24e38e5 100644
--- a/psalm-baseline.xml
+++ b/psalm-baseline.xml
@@ -11,11 +11,6 @@
       <code><![CDATA[AdmissionRequirementTranslatedType]]></code>
     </InvalidReturnType>
   </file>
-  <file src="src/Application/DegreeProgramViewTranslated.php">
-    <RiskyTruthyFalsyComparison>
-      <code><![CDATA[empty($data[self::TRANSLATIONS])]]></code>
-    </RiskyTruthyFalsyComparison>
-  </file>
   <file src="src/Application/Filter/AdmissionRequirementTypeFilter.php">
     <RiskyTruthyFalsyComparison>
       <code><![CDATA[$sanitizedValue]]></code>
diff --git a/src/Application/Cache/CacheInvalidator.php b/src/Application/Cache/CacheInvalidator.php
index 5528a98..601ff5b 100644
--- a/src/Application/Cache/CacheInvalidator.php
+++ b/src/Application/Cache/CacheInvalidator.php
@@ -11,6 +11,9 @@
 use Psr\SimpleCache\CacheInterface;
 use Psr\SimpleCache\InvalidArgumentException;
 
+/**
+ * @psalm-import-type Reason from CacheInvalidated
+ */
 final class CacheInvalidator
 {
     public function __construct(
@@ -21,7 +24,10 @@ public function __construct(
     ) {
     }
 
-    public function invalidateFully(): bool
+    /**
+     * @psalm-param Reason $reason
+     */
+    public function invalidateFully(string $reason = CacheInvalidated::ENFORCED): bool
     {
         $result = $this->cache->clear();
         if (!$result) {
@@ -30,16 +36,17 @@ public function invalidateFully(): bool
         }
 
         $this->logger->info('Successful degree program full cache invalidation.');
-        $this->eventDispatcher->dispatch(CacheInvalidated::fully());
+        $this->eventDispatcher->dispatch(CacheInvalidated::fully($reason));
         return true;
     }
 
     /**
      * @psalm-param array<int> $ids
+     * @psalm-param Reason $reason
      *
      * @throws InvalidArgumentException
      */
-    public function invalidatePartially(array $ids): bool
+    public function invalidatePartially(array $ids, string $reason = CacheInvalidated::ENFORCED): bool
     {
         if (count($ids) === 0) {
             $this->logger->debug(
@@ -81,7 +88,7 @@ public function invalidatePartially(array $ids): bool
                 implode(', ', $ids)
             )
         );
-        $this->eventDispatcher->dispatch(CacheInvalidated::partially($ids));
+        $this->eventDispatcher->dispatch(CacheInvalidated::partially($ids, $reason));
 
         return true;
     }
diff --git a/src/Application/DegreeProgramViewTranslated.php b/src/Application/DegreeProgramViewTranslated.php
index e1d50cd..f119eb3 100644
--- a/src/Application/DegreeProgramViewTranslated.php
+++ b/src/Application/DegreeProgramViewTranslated.php
@@ -79,11 +79,15 @@
  * }
  * @psalm-type DegreeProgramViewTranslatedArrayType = DegreeProgramTranslation & array{
  *      id: int,
+ *      date: string,
+ *      modified: string,
  *      translations: array<LanguageCodes, DegreeProgramTranslation>,
  * }
  */
 final class DegreeProgramViewTranslated implements JsonSerializable
 {
+    public const DATE = 'date';
+    public const MODIFIED = 'modified';
     public const LINK = 'link';
     public const LANG = 'lang';
     public const ADMISSION_REQUIREMENT_LINK = 'admission_requirement_link';
@@ -94,6 +98,8 @@ final class DegreeProgramViewTranslated implements JsonSerializable
 
     public function __construct(
         private DegreeProgramId $id,
+        private string $date,
+        private string $modified,
         private string $link,
         private string $slug,
         /**
@@ -160,6 +166,8 @@ public static function empty(int $id, string $languageCode): self
     {
         return new self(
             DegreeProgramId::fromInt($id),
+            date: '',
+            modified: '',
             link: '',
             slug: '',
             lang: $languageCode,
@@ -220,6 +228,8 @@ public static function empty(int $id, string $languageCode): self
     /**
      * @psalm-param DegreeProgramTranslation & array{
      *      id: int | numeric-string,
+     *      date: string,
+     *      modified: string,
      *      translations?: array<LanguageCodes, DegreeProgramTranslation>,
      * } $data
      *
@@ -229,6 +239,8 @@ public static function fromArray(array $data): self
     {
         $main = new self(
             id: DegreeProgramId::fromInt((int) $data[DegreeProgram::ID]),
+            date: $data[self::DATE] ?? '',
+            modified: $data[self::MODIFIED] ?? '',
             link: $data[self::LINK],
             slug: $data[DegreeProgram::SLUG],
             lang: $data[self::LANG],
@@ -285,12 +297,14 @@ public static function fromArray(array $data): self
             campoKeys: CampoKeys::fromArray($data[DegreeProgram::CAMPO_KEYS] ?? []),
         );
 
-        if (empty($data[self::TRANSLATIONS])) {
+        if (!isset($data[self::TRANSLATIONS]) || count($data[self::TRANSLATIONS]) === 0) {
             return $main;
         }
 
         foreach ($data[self::TRANSLATIONS] as $translationData) {
             $translationData[DegreeProgram::ID] = $data[DegreeProgram::ID];
+            $translationData[self::DATE] = $data[self::DATE];
+            $translationData[self::MODIFIED] = $data[self::MODIFIED];
             $main = $main->withTranslation(self::fromArray($translationData), $translationData[self::LANG]);
         }
 
@@ -304,6 +318,8 @@ public function asArray(): array
     {
         return [
             DegreeProgram::ID => $this->id->asInt(),
+            self::DATE => $this->date,
+            self::MODIFIED => $this->modified,
             self::LINK => $this->link,
             DegreeProgram::SLUG => $this->slug,
             self::LANG => $this->lang,
@@ -408,7 +424,12 @@ private function translationsAsArray(): array
     {
         return array_map(static function (DegreeProgramViewTranslated $view): array {
             $result = $view->asArray();
-            unset($result[DegreeProgram::ID], $result[self::TRANSLATIONS]);
+            unset(
+                $result[DegreeProgram::ID],
+                $result[self::DATE],
+                $result[self::MODIFIED],
+                $result[self::TRANSLATIONS]
+            );
 
             return $result;
         }, $this->translations);
@@ -419,6 +440,16 @@ public function id(): int
         return $this->id->asInt();
     }
 
+    public function date(): string
+    {
+        return $this->date;
+    }
+
+    public function modified(): string
+    {
+        return $this->modified;
+    }
+
     public function link(): string
     {
         return $this->link;
diff --git a/src/Application/Event/CacheInvalidated.php b/src/Application/Event/CacheInvalidated.php
index c94b7da..a333745 100644
--- a/src/Application/Event/CacheInvalidated.php
+++ b/src/Application/Event/CacheInvalidated.php
@@ -6,30 +6,41 @@
 
 use Stringable;
 
+/**
+ * @psalm-type Reason = self::ENFORCED | self::DATA_CHANGED
+ */
 final class CacheInvalidated implements Stringable
 {
     public const NAME = 'degree_program_cache_invalidated';
+    public const ENFORCED = 'enforced';
+    public const DATA_CHANGED = 'data_changed';
 
     /**
      * @param array<int> $ids
+     * @param Reason $reason
      */
     private function __construct(
         private bool $isFully,
         private array $ids,
+        private string $reason,
     ) {
     }
 
-    public static function fully(): self
+    /**
+     * @param Reason $reason
+     */
+    public static function fully(string $reason): self
     {
-        return new self(true, []);
+        return new self(true, [], $reason);
     }
 
     /**
      * @param array<int> $ids
+     * @param Reason $reason
      */
-    public static function partially(array $ids): self
+    public static function partially(array $ids, string $reason): self
     {
-        return new self(false, $ids);
+        return new self(false, $ids, $reason);
     }
 
     public function isFully(): bool
@@ -45,6 +56,14 @@ public function ids(): array
         return $this->ids;
     }
 
+    /**
+     * @return Reason
+     */
+    public function reason(): string
+    {
+        return $this->reason;
+    }
+
     public function __toString(): string
     {
         return self::NAME;
diff --git a/src/Infrastructure/Repository/TimestampRepository.php b/src/Infrastructure/Repository/TimestampRepository.php
new file mode 100644
index 0000000..7affc30
--- /dev/null
+++ b/src/Infrastructure/Repository/TimestampRepository.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Fau\DegreeProgram\Common\Infrastructure\Repository;
+
+use DateTimeImmutable;
+use DateTimeInterface;
+use Fau\DegreeProgram\Common\Domain\DegreeProgramId;
+
+final class TimestampRepository
+{
+    private const MODIFIED_META_KEY = 'degree_program_modified';
+
+    public function created(DegreeProgramId $id): ?DateTimeInterface
+    {
+        $postDateTime = get_post_datetime($id->asInt());
+
+        return $postDateTime instanceof DateTimeInterface ? $postDateTime : null;
+    }
+
+    /**
+     * The custom field is updated when the degree program or related settings or terms are updated.
+     * If the custom field does not exist,
+     * we fall back to the core WordPress "post modified" property.
+     */
+    public function modified(DegreeProgramId $id): ?DateTimeInterface
+    {
+        $timestamp = (int) get_post_meta($id->asInt(), self::MODIFIED_META_KEY, true);
+
+        if ($timestamp < 1) {
+            $timestamp = get_post_timestamp($id->asInt(), 'modified');
+        }
+
+        if (!is_int($timestamp)) {
+            return null;
+        }
+
+        $dateTime = new DateTimeImmutable();
+        $dateTime = $dateTime->setTimestamp($timestamp);
+
+        return $dateTime->setTimezone(wp_timezone());
+    }
+
+    public function updateModified(DegreeProgramId $id): void
+    {
+        update_post_meta($id->asInt(), self::MODIFIED_META_KEY, time());
+    }
+}
diff --git a/src/Infrastructure/Repository/WordPressDatabaseDegreeProgramViewRepository.php b/src/Infrastructure/Repository/WordPressDatabaseDegreeProgramViewRepository.php
index 7d32c54..efdb713 100644
--- a/src/Infrastructure/Repository/WordPressDatabaseDegreeProgramViewRepository.php
+++ b/src/Infrastructure/Repository/WordPressDatabaseDegreeProgramViewRepository.php
@@ -4,6 +4,7 @@
 
 namespace Fau\DegreeProgram\Common\Infrastructure\Repository;
 
+use DateTimeInterface;
 use Fau\DegreeProgram\Common\Application\AdmissionRequirementsTranslated;
 use Fau\DegreeProgram\Common\Application\AdmissionRequirementTranslated;
 use Fau\DegreeProgram\Common\Application\ConditionalFieldsFilter;
@@ -33,11 +34,14 @@
  */
 final class WordPressDatabaseDegreeProgramViewRepository implements DegreeProgramViewRepository
 {
+    private const DATE_TIME_FORMAT = DateTimeInterface::RFC3339;
+
     public function __construct(
         private DegreeProgramRepository $degreeProgramRepository,
         private HtmlDegreeProgramSanitizer $htmlContentSanitizer,
         private ConditionalFieldsFilter $conditionalFieldsFilter,
         private FacultyRepository $facultyRepository,
+        private TimestampRepository $timestampRepository,
     ) {
     }
 
@@ -100,6 +104,8 @@ private function translateDegreeProgram(
 
         return new DegreeProgramViewTranslated(
             id: $raw->id(),
+            date: (string) $this->timestampRepository->created($raw->id())?->format(self::DATE_TIME_FORMAT),
+            modified: (string) $this->timestampRepository->modified($raw->id())?->format(self::DATE_TIME_FORMAT),
             link: $this->link(
                 $raw->id()->asInt(),
                 $raw->slug(),
diff --git a/src/Infrastructure/RestApi/TranslatedDegreeProgramController.php b/src/Infrastructure/RestApi/TranslatedDegreeProgramController.php
index 5248144..848a2a9 100644
--- a/src/Infrastructure/RestApi/TranslatedDegreeProgramController.php
+++ b/src/Infrastructure/RestApi/TranslatedDegreeProgramController.php
@@ -315,6 +315,24 @@ public function get_item_schema(): array
                 ),
                 'type' => 'integer',
             ],
+            DegreeProgramViewTranslated::DATE => [
+                'description' => _x(
+                    'The date the degree program was created.',
+                    'rest_api: schema item description',
+                    'fau-degree-program-common'
+                ),
+                'type' => 'string',
+                'format' => 'date-time',
+            ],
+            DegreeProgramViewTranslated::MODIFIED => [
+                'description' => _x(
+                    'The date the degree program was last modified.',
+                    'rest_api: schema item description',
+                    'fau-degree-program-common'
+                ),
+                'type' => 'string',
+                'format' => 'date-time',
+            ],
             DegreeProgram::FEATURED_IMAGE => [
                 'description' => _x(
                     'Feature image.',