diff --git a/.changeset/old-onions-attend.md b/.changeset/old-onions-attend.md
new file mode 100644
index 0000000..9763399
--- /dev/null
+++ b/.changeset/old-onions-attend.md
@@ -0,0 +1,5 @@
+---
+"posthog-php": patch
+---
+
+Move const inside class to prevent memory leaks in worker mode
diff --git a/lib/Client.php b/lib/Client.php
index 90b5d35..cbb5691 100644
--- a/lib/Client.php
+++ b/lib/Client.php
@@ -10,13 +10,12 @@
 use PostHog\Consumer\Socket;
 use Symfony\Component\Clock\Clock;
 
-const SIZE_LIMIT = 50_000;
-
 /**
  * PostHog PHP SDK client for event capture, user identification, feature flags, and error tracking.
  */
 class Client implements FeatureFlagEvaluationsHost
 {
+    private const SIZE_LIMIT = 50_000;
     private const CONSUMERS = [
         "socket" => Socket::class,
         "file" => File::class,
@@ -167,7 +166,7 @@ public function __construct(
         $this->groupTypeMapping = [];
         $this->cohorts = [];
         $this->featureFlagsByKey = [];
-        $this->distinctIdsFeatureFlagsReported = new SizeLimitedHash(SIZE_LIMIT);
+        $this->distinctIdsFeatureFlagsReported = new SizeLimitedHash(self::SIZE_LIMIT);
         $this->flagsEtag = null;
 
         if ($this->enabled) {
diff --git a/lib/FeatureFlag.php b/lib/FeatureFlag.php
index dc2c2ab..3c1f77a 100644
--- a/lib/FeatureFlag.php
+++ b/lib/FeatureFlag.php
@@ -4,8 +4,6 @@
 
 use Symfony\Component\Clock\Clock;
 
-const LONG_SCALE = 0xfffffffffffffff;
-
 /**
  * Local feature flag matching helpers.
  *
@@ -13,6 +11,8 @@
  */
 class FeatureFlag
 {
+    private const LONG_SCALE = 0xfffffffffffffff;
+
     /**
      * Match a single property filter against provided property values.
      *
@@ -585,7 +585,7 @@ private static function hash($key, $distinctId, $salt = "")
         $hashKey = sprintf("%s.%s%s", $key, $distinctId, $salt);
         $hashVal = base_convert(substr(sha1($hashKey), 0, 15), 16, 10);
 
-        return $hashVal / LONG_SCALE;
+        return $hashVal / self::LONG_SCALE;
     }
 
     private static function getMatchingVariant($flag, $distinctId)