diff --git a/src/BaseEloquentRepository.php b/src/BaseEloquentRepository.php
index 5dcd07c..1957147 100644
--- a/src/BaseEloquentRepository.php
+++ b/src/BaseEloquentRepository.php
@@ -50,7 +50,7 @@ protected function getDisplayField(): string
     /**
      * {@inheritDoc}
      */
-    public function findOne(int|string $primaryKey = null): ?Model
+    public function findOne(int|string|null $primaryKey = null): ?Model
     {
         if (func_num_args() > 0) {
             $this->applyConditions(['id' => $primaryKey]);
@@ -68,7 +68,7 @@ public function findOne(int|string $primaryKey = null): ?Model
     /**
      * {@inheritDoc}
      */
-    public function findOneOrFail(int|string $primaryKey = null): Model
+    public function findOneOrFail(int|string|null $primaryKey = null): Model
     {
         if (func_num_args() > 0) {
             $this->applyConditions(['id' => $primaryKey]);
@@ -116,7 +116,7 @@ public function findAll(array $options = []): EloquentCollection
     /**
      * {@inheritDoc}
      */
-    public function findList(string $key = null, string $value = null): Collection
+    public function findList(?string $key = null, ?string $value = null): Collection
     {
         $this->applyCriteria();
         $this->applyRelations();
@@ -138,7 +138,7 @@ public function findList(string $key = null, string $value = null): Collection
     /**
      * {@inheritDoc}
      */
-    public function paginate(int $perPage = null): Paginator
+    public function paginate(?int $perPage = null): Paginator
     {
         $perPage = $this->preparePageSize($perPage);
 
@@ -156,7 +156,7 @@ public function paginate(int $perPage = null): Paginator
      *
      * @throws \InvalidArgumentException
      */
-    protected function preparePageSize(int $perPage = null): int
+    protected function preparePageSize(?int $perPage = null): int
     {
         if ($perPage <= 0) {
             throw new InvalidArgumentException('Invalid page size');
diff --git a/src/Contracts/RepositoryInterface.php b/src/Contracts/RepositoryInterface.php
index 84567d9..016b4ce 100644
--- a/src/Contracts/RepositoryInterface.php
+++ b/src/Contracts/RepositoryInterface.php
@@ -13,14 +13,14 @@ interface RepositoryInterface
      * It applies the conditions, criteria, relations, and order by to the query,
      * then gets the first result and resets the query
      */
-    public function findOne(int|string $primaryKey = null): ?Model;
+    public function findOne(int|string|null $primaryKey = null): ?Model;
 
     /**
      * If the result of the `findOne` function is null, throw a `ModelNotFoundException`
      *
      * @throws \Illuminate\Database\Eloquent\ModelNotFoundException
      */
-    public function findOneOrFail(int|string $primaryKey = null): Model;
+    public function findOneOrFail(int|string|null $primaryKey = null): Model;
 
     /**
      * It takes an array of options, applies them to the query, executes the query, and returns the results.
@@ -36,12 +36,12 @@ public function findAll(array $options = []): EloquentCollection;
      * @param  string|null  $value The field to use as the value of the select list.
      * @return \Illuminate\Support\Collection A collection of key value pairs.
      */
-    public function findList(string $key = null, string $value = null): Collection;
+    public function findList(?string $key = null, ?string $value = null): Collection;
 
     /**
      * It applies the criteria, relations, and order by to the query, then paginates the results and resets the query
      */
-    public function paginate(int $perPage = null): Paginator;
+    public function paginate(?int $perPage = null): Paginator;
 
     /**
      * Add a criteria to the query.
diff --git a/src/Contracts/SearchableRepositoryInterface.php b/src/Contracts/SearchableRepositoryInterface.php
index 020673d..01db2d4 100644
--- a/src/Contracts/SearchableRepositoryInterface.php
+++ b/src/Contracts/SearchableRepositoryInterface.php
@@ -9,5 +9,5 @@ interface SearchableRepositoryInterface
     /**
      * Search for records based on the provided query parameters and paginate the results.
      */
-    public function search(array $queryParams, int $perPage = null): Paginator;
+    public function search(array $queryParams, ?int $perPage = null): Paginator;
 }
diff --git a/src/Traits/Searchable.php b/src/Traits/Searchable.php
index b82c169..9ab41b0 100644
--- a/src/Traits/Searchable.php
+++ b/src/Traits/Searchable.php
@@ -12,7 +12,7 @@ trait Searchable
 {
     abstract protected function getFilterManager(): BaseFilter;
 
-    public function search(array $queryParams, int $perPage = null): Paginator
+    public function search(array $queryParams, ?int $perPage = null): Paginator
     {
         $this->setQuery($this->getFilterManager()->applyFilter($queryParams));