diff --git a/CHANGELOG.md b/CHANGELOG.md
index ea380119..17ba8eec 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,8 @@
   - [Notyf] Dispatch events: `flasher:notyf:click`, `flasher:notyf:dismiss`
   - [Themes] Dispatch events: `flasher:theme:click` (generic) and `flasher:theme:{name}:click` (specific)
   - [Laravel] Add LivewireListener classes for all adapters and themes to enable Livewire event handling
+* fix [Flasher] Fix FilterCriteria uninitialized property error when constructed with empty array
+* fix [Flasher] Fix null comparison issues in PriorityCriteria, HopsCriteria, and DelayCriteria that relied on PHP's implicit null-to-0 coercion
 
 ## [v2.1.3](https://github.com/php-flasher/php-flasher/compare/v2.1.2...v2.1.3) - 2025-01-25
 
diff --git a/src/Prime/Storage/Filter/Criteria/DelayCriteria.php b/src/Prime/Storage/Filter/Criteria/DelayCriteria.php
index 5aa7b88d..55a596dd 100644
--- a/src/Prime/Storage/Filter/Criteria/DelayCriteria.php
+++ b/src/Prime/Storage/Filter/Criteria/DelayCriteria.php
@@ -46,14 +46,9 @@ final readonly class DelayCriteria implements CriteriaInterface
 
         $delay = $stamp->getDelay();
 
-        if (null === $this->maxDelay) {
-            return $delay >= $this->minDelay;
-        }
+        $meetsMin = null === $this->minDelay || $delay >= $this->minDelay;
+        $meetsMax = null === $this->maxDelay || $delay <= $this->maxDelay;
 
-        if ($delay <= $this->maxDelay) {
-            return $delay >= $this->minDelay;
-        }
-
-        return false;
+        return $meetsMin && $meetsMax;
     }
 }
diff --git a/src/Prime/Storage/Filter/Criteria/FilterCriteria.php b/src/Prime/Storage/Filter/Criteria/FilterCriteria.php
index 79cb3b2f..9d2125bf 100644
--- a/src/Prime/Storage/Filter/Criteria/FilterCriteria.php
+++ b/src/Prime/Storage/Filter/Criteria/FilterCriteria.php
@@ -11,7 +11,7 @@ final class FilterCriteria implements CriteriaInterface
     /**
      * @var \Closure[]
      */
-    private array $callbacks;
+    private array $callbacks = [];
 
     /**
      * @throws \InvalidArgumentException
diff --git a/src/Prime/Storage/Filter/Criteria/HopsCriteria.php b/src/Prime/Storage/Filter/Criteria/HopsCriteria.php
index 5efa2f26..f07152f7 100644
--- a/src/Prime/Storage/Filter/Criteria/HopsCriteria.php
+++ b/src/Prime/Storage/Filter/Criteria/HopsCriteria.php
@@ -11,9 +11,9 @@ final readonly class HopsCriteria implements CriteriaInterface
 {
     use RangeExtractor;
 
-    private readonly ?int $minAmount;
+    private ?int $minAmount;
 
-    private readonly ?int $maxAmount;
+    private ?int $maxAmount;
 
     /**
      * @throws \InvalidArgumentException
@@ -44,14 +44,11 @@ final readonly class HopsCriteria implements CriteriaInterface
             return false;
         }
 
-        if (null === $this->maxAmount) {
-            return $stamp->getAmount() >= $this->minAmount;
-        }
+        $amount = $stamp->getAmount();
 
-        if ($stamp->getAmount() <= $this->maxAmount) {
-            return $stamp->getAmount() >= $this->minAmount;
-        }
+        $meetsMin = null === $this->minAmount || $amount >= $this->minAmount;
+        $meetsMax = null === $this->maxAmount || $amount <= $this->maxAmount;
 
-        return false;
+        return $meetsMin && $meetsMax;
     }
 }
diff --git a/src/Prime/Storage/Filter/Criteria/PriorityCriteria.php b/src/Prime/Storage/Filter/Criteria/PriorityCriteria.php
index 18345b8a..0944cb6c 100644
--- a/src/Prime/Storage/Filter/Criteria/PriorityCriteria.php
+++ b/src/Prime/Storage/Filter/Criteria/PriorityCriteria.php
@@ -46,14 +46,9 @@ final readonly class PriorityCriteria implements CriteriaInterface
 
         $priority = $stamp->getPriority();
 
-        if (null === $this->maxPriority) {
-            return $priority >= $this->minPriority;
-        }
+        $meetsMin = null === $this->minPriority || $priority >= $this->minPriority;
+        $meetsMax = null === $this->maxPriority || $priority <= $this->maxPriority;
 
-        if ($priority <= $this->maxPriority) {
-            return $priority >= $this->minPriority;
-        }
-
-        return false;
+        return $meetsMin && $meetsMax;
     }
 }
diff --git a/tests/Prime/Storage/Filter/Criteria/DelayCriteriaTest.php b/tests/Prime/Storage/Filter/Criteria/DelayCriteriaTest.php
index 088ae109..b8dc65af 100644
--- a/tests/Prime/Storage/Filter/Criteria/DelayCriteriaTest.php
+++ b/tests/Prime/Storage/Filter/Criteria/DelayCriteriaTest.php
@@ -248,4 +248,52 @@ final class DelayCriteriaTest extends TestCase
 
         $this->assertCount(3, $result);
     }
+
+    public function testMatchWithOnlyMaxAndNullMin(): void
+    {
+        // This test verifies explicit null handling for min
+        // Previously relied on PHP's implicit null-to-0 coercion
+        $envelope = new Envelope(new Notification(), [new DelayStamp(3)]);
+
+        $criteria = new DelayCriteria(['max' => 5]);
+
+        // With min=null and max=5, delay=3 should match
+        $this->assertTrue($criteria->match($envelope));
+    }
+
+    public function testMatchWithOnlyMaxRejectsHigherDelay(): void
+    {
+        $envelope = new Envelope(new Notification(), [new DelayStamp(10)]);
+
+        $criteria = new DelayCriteria(['max' => 5]);
+
+        // With min=null and max=5, delay=10 should NOT match
+        $this->assertFalse($criteria->match($envelope));
+    }
+
+    public function testMatchWithBothNullMinAndMax(): void
+    {
+        // When both min and max are null, all envelopes with delay stamp should match
+        $envelope = new Envelope(new Notification(), [new DelayStamp(100)]);
+
+        $criteria = new DelayCriteria([]);
+
+        $this->assertTrue($criteria->match($envelope));
+    }
+
+    public function testApplyWithNullMinAndMaxMatchesAll(): void
+    {
+        $envelopes = [
+            new Envelope(new Notification(), [new DelayStamp(0)]),
+            new Envelope(new Notification(), [new DelayStamp(50)]),
+            new Envelope(new Notification(), [new DelayStamp(100)]),
+        ];
+
+        $criteria = new DelayCriteria([]);
+
+        $result = $criteria->apply($envelopes);
+
+        // All envelopes with delay stamp should match when no constraints
+        $this->assertCount(3, $result);
+    }
 }
diff --git a/tests/Prime/Storage/Filter/Criteria/FilterCriteriaTest.php b/tests/Prime/Storage/Filter/Criteria/FilterCriteriaTest.php
index 299dcb0b..0d7ecf23 100644
--- a/tests/Prime/Storage/Filter/Criteria/FilterCriteriaTest.php
+++ b/tests/Prime/Storage/Filter/Criteria/FilterCriteriaTest.php
@@ -166,4 +166,32 @@ final class FilterCriteriaTest extends TestCase
         $this->assertSame(['first', 'second'], $order);
         $this->assertCount(2, $result);
     }
+
+    public function testConstructorWithEmptyArrayDoesNotThrow(): void
+    {
+        // This test verifies the fix for uninitialized $callbacks property
+        // Previously, new FilterCriteria([]) would leave $callbacks uninitialized
+        // causing "must not be accessed before initialization" error on apply()
+        $criteria = new FilterCriteria([]);
+
+        $envelopes = [new Envelope(new Notification())];
+        $result = $criteria->apply($envelopes);
+
+        // With no callbacks, envelopes should pass through unchanged
+        $this->assertSame($envelopes, $result);
+    }
+
+    public function testApplyWithEmptyCallbacksReturnsEnvelopesUnchanged(): void
+    {
+        $criteria = new FilterCriteria([]);
+
+        $notification = new Notification();
+        $notification->setMessage('test');
+        $envelopes = [new Envelope($notification)];
+
+        $result = $criteria->apply($envelopes);
+
+        $this->assertCount(1, $result);
+        $this->assertSame('test', $result[0]->getMessage());
+    }
 }
diff --git a/tests/Prime/Storage/Filter/Criteria/HopsCriteriaTest.php b/tests/Prime/Storage/Filter/Criteria/HopsCriteriaTest.php
index 25d0fe5d..fc46593c 100644
--- a/tests/Prime/Storage/Filter/Criteria/HopsCriteriaTest.php
+++ b/tests/Prime/Storage/Filter/Criteria/HopsCriteriaTest.php
@@ -229,4 +229,52 @@ final class HopsCriteriaTest extends TestCase
 
         $this->assertCount(1, $result);
     }
+
+    public function testMatchWithOnlyMaxAndNullMin(): void
+    {
+        // This test verifies explicit null handling for min
+        // Previously relied on PHP's implicit null-to-0 coercion
+        $envelope = new Envelope(new Notification(), [new HopsStamp(2)]);
+
+        $criteria = new HopsCriteria(['max' => 5]);
+
+        // With min=null and max=5, hops=2 should match
+        $this->assertTrue($criteria->match($envelope));
+    }
+
+    public function testMatchWithOnlyMaxRejectsHigherHops(): void
+    {
+        $envelope = new Envelope(new Notification(), [new HopsStamp(10)]);
+
+        $criteria = new HopsCriteria(['max' => 5]);
+
+        // With min=null and max=5, hops=10 should NOT match
+        $this->assertFalse($criteria->match($envelope));
+    }
+
+    public function testMatchWithBothNullMinAndMax(): void
+    {
+        // When both min and max are null, all envelopes with hops stamp should match
+        $envelope = new Envelope(new Notification(), [new HopsStamp(100)]);
+
+        $criteria = new HopsCriteria([]);
+
+        $this->assertTrue($criteria->match($envelope));
+    }
+
+    public function testApplyWithNullMinAndMaxMatchesAll(): void
+    {
+        $envelopes = [
+            new Envelope(new Notification(), [new HopsStamp(1)]),
+            new Envelope(new Notification(), [new HopsStamp(50)]),
+            new Envelope(new Notification(), [new HopsStamp(100)]),
+        ];
+
+        $criteria = new HopsCriteria([]);
+
+        $result = $criteria->apply($envelopes);
+
+        // All envelopes with hops stamp should match when no constraints
+        $this->assertCount(3, $result);
+    }
 }
diff --git a/tests/Prime/Storage/Filter/Criteria/PriorityCriteriaTest.php b/tests/Prime/Storage/Filter/Criteria/PriorityCriteriaTest.php
index ebae681c..5c0607e4 100644
--- a/tests/Prime/Storage/Filter/Criteria/PriorityCriteriaTest.php
+++ b/tests/Prime/Storage/Filter/Criteria/PriorityCriteriaTest.php
@@ -245,4 +245,52 @@ final class PriorityCriteriaTest extends TestCase
 
         $this->assertCount(1, $result);
     }
+
+    public function testMatchWithOnlyMaxAndNullMin(): void
+    {
+        // This test verifies explicit null handling for min
+        // Previously relied on PHP's implicit null-to-0 coercion
+        $envelope = new Envelope(new Notification(), [new PriorityStamp(3)]);
+
+        $criteria = new PriorityCriteria(['max' => 5]);
+
+        // With min=null and max=5, priority 3 should match
+        $this->assertTrue($criteria->match($envelope));
+    }
+
+    public function testMatchWithOnlyMaxRejectsHigherPriority(): void
+    {
+        $envelope = new Envelope(new Notification(), [new PriorityStamp(10)]);
+
+        $criteria = new PriorityCriteria(['max' => 5]);
+
+        // With min=null and max=5, priority 10 should NOT match
+        $this->assertFalse($criteria->match($envelope));
+    }
+
+    public function testMatchWithBothNullMinAndMax(): void
+    {
+        // When both min and max are null, all envelopes with priority stamp should match
+        $envelope = new Envelope(new Notification(), [new PriorityStamp(100)]);
+
+        $criteria = new PriorityCriteria([]);
+
+        $this->assertTrue($criteria->match($envelope));
+    }
+
+    public function testApplyWithNullMinAndMaxMatchesAll(): void
+    {
+        $envelopes = [
+            new Envelope(new Notification(), [new PriorityStamp(-100)]),
+            new Envelope(new Notification(), [new PriorityStamp(0)]),
+            new Envelope(new Notification(), [new PriorityStamp(100)]),
+        ];
+
+        $criteria = new PriorityCriteria([]);
+
+        $result = $criteria->apply($envelopes);
+
+        // All envelopes with priority stamp should match when no constraints
+        $this->assertCount(3, $result);
+    }
 }