diff --git a/cloud/src/Ingest/EventValidator.php b/cloud/src/Ingest/EventValidator.php
new file mode 100644
index 0000000..a119935
--- /dev/null
+++ b/cloud/src/Ingest/EventValidator.php
@@ -0,0 +1,40 @@
+<?php
+declare(strict_types=1);
+namespace App\Ingest;
+
+final class EventValidator
+{
+    private const TYPES = ['fall','no_motion','immobility','ghost','zone_warning',
+        'zone_restricted','pinch','monitoring_degraded','device_fault'];
+    private const SEVERITIES = ['critical','high','warning','info'];
+    private const REQUIRED = ['device_id','camera_id','event_type','severity','occurred_at'];
+
+    public static function validate(array $p): array
+    {
+        $errors = [];
+        foreach (self::REQUIRED as $k) {
+            if (!array_key_exists($k, $p) || $p[$k] === '' || $p[$k] === null) $errors[] = "missing:$k";
+        }
+        if (isset($p['event_type']) && !in_array($p['event_type'], self::TYPES, true)) $errors[] = 'bad:event_type';
+        if (isset($p['severity']) && !in_array($p['severity'], self::SEVERITIES, true)) $errors[] = 'bad:severity';
+        $snaps = $p['snapshots'] ?? [];
+        if (!is_array($snaps)) $errors[] = 'bad:snapshots';
+        elseif (count($snaps) > 3) $errors[] = 'too_many:snapshots';
+        else foreach ($snaps as $s) if (!is_string($s)) { $errors[] = 'bad:snapshot_item'; break; }
+
+        if ($errors) return ['ok' => false, 'errors' => $errors, 'clean' => []];
+
+        $clean = [
+            'device_id' => (string)$p['device_id'],
+            'camera_id' => (string)$p['camera_id'],
+            'event_type' => (string)$p['event_type'],
+            'severity' => (string)$p['severity'],
+            'track_id' => isset($p['track_id']) ? (int)$p['track_id'] : null,
+            'zone_id' => isset($p['zone_id']) ? (string)$p['zone_id'] : null,
+            'occurred_at' => (float)$p['occurred_at'],
+            'duration_s' => (float)($p['duration_s'] ?? 0.0),
+            'metrics' => is_array($p['metrics'] ?? null) ? $p['metrics'] : [],
+        ];
+        return ['ok' => true, 'errors' => [], 'clean' => $clean];
+    }
+}
diff --git a/cloud/tests/EventValidatorTest.php b/cloud/tests/EventValidatorTest.php
new file mode 100644
index 0000000..0bcfcca
--- /dev/null
+++ b/cloud/tests/EventValidatorTest.php
@@ -0,0 +1,34 @@
+<?php
+declare(strict_types=1);
+namespace App\Tests;
+use App\Ingest\EventValidator;
+use PHPUnit\Framework\TestCase;
+
+final class EventValidatorTest extends TestCase
+{
+    private function valid(): array {
+        return ['device_id' => 'pi-1', 'camera_id' => 'cam-1', 'event_type' => 'fall',
+                'severity' => 'high', 'occurred_at' => 1000.0, 'snapshots' => ['aGk=']];
+    }
+    public function testAcceptsValid(): void {
+        $r = EventValidator::validate($this->valid());
+        $this->assertTrue($r['ok'], implode(',', $r['errors']));
+        $this->assertSame('fall', $r['clean']['event_type']);
+    }
+    public function testRejectsUnknownEventType(): void {
+        $p = $this->valid(); $p['event_type'] = 'explode';
+        $this->assertFalse(EventValidator::validate($p)['ok']);
+    }
+    public function testRejectsUnknownSeverity(): void {
+        $p = $this->valid(); $p['severity'] = 'ULTRA';
+        $this->assertFalse(EventValidator::validate($p)['ok']);
+    }
+    public function testRejectsMissingRequired(): void {
+        $p = $this->valid(); unset($p['device_id']);
+        $this->assertFalse(EventValidator::validate($p)['ok']);
+    }
+    public function testRejectsTooManySnapshots(): void {
+        $p = $this->valid(); $p['snapshots'] = ['a', 'b', 'c', 'd'];
+        $this->assertFalse(EventValidator::validate($p)['ok']);
+    }
+}