diff --git a/app/Analyzers/DockerHub/BaseEvent.php b/app/Analyzers/DockerHub/BaseEvent.php
--- a/app/Analyzers/DockerHub/BaseEvent.php
+++ b/app/Analyzers/DockerHub/BaseEvent.php
@@ -14,7 +14,7 @@
      *
      * @param \stdClass $payload The payload to analyze
      */
-    public function __construct ($payload) {
+    public function __construct (\stdClass $payload) {
         $this->payload = $payload;
     }
 
diff --git a/app/Analyzers/DockerHub/BuildFailureEvent.php b/app/Analyzers/DockerHub/BuildFailureEvent.php
--- a/app/Analyzers/DockerHub/BuildFailureEvent.php
+++ b/app/Analyzers/DockerHub/BuildFailureEvent.php
@@ -11,7 +11,7 @@
      *
      * @param \stdClass $payload The payload to analyze
      */
-    public function __construct ($payload) {
+    public function __construct (\stdClass $payload) {
         parent::__construct($payload);
         $this->payload = $this->getMailGunPayload();
     }
diff --git a/app/Analyzers/GitHub/Events/RepositoryEvent.php b/app/Analyzers/GitHub/Events/RepositoryEvent.php
--- a/app/Analyzers/GitHub/Events/RepositoryEvent.php
+++ b/app/Analyzers/GitHub/Events/RepositoryEvent.php
@@ -13,9 +13,10 @@
      * Determines if the action is valid.
      *
      * @param string $action The action to check
+     *
      * @return bool true if the action is valid; otherwise, false
      */
-    protected static function isValidAction ($action) {
+    protected static function isValidAction (string $action) {
         $actions = ['created', 'deleted', 'publicized', 'privatized'];
         return in_array($action, $actions);
     }
diff --git a/app/Analyzers/GitHub/Events/WithCommit.php b/app/Analyzers/GitHub/Events/WithCommit.php
--- a/app/Analyzers/GitHub/Events/WithCommit.php
+++ b/app/Analyzers/GitHub/Events/WithCommit.php
@@ -23,9 +23,10 @@
      * Extracts the commit title from the whole commit message.
      *
      * @param string $message The commit message
+     *
      * @return string The commit title
      */
-    public static function getCommitTitle ($message) {
+    public static function getCommitTitle (string $message) {
         // Discards extra lines
         $pos = strpos($message, "\n");
         if ($pos > 0) {
diff --git a/app/Config/Services/Services.php b/app/Config/Services/Services.php
--- a/app/Config/Services/Services.php
+++ b/app/Config/Services/Services.php
@@ -94,7 +94,7 @@
     public function findServiceByProperty (
         string $gate,
         string $property,
-        $value
+        mixed $value
     ) : ?Service {
         foreach ($this->services as $service) {
             if ($service->gate === $gate && $service->$property === $value) {
diff --git a/app/Events/DockerHubPayloadEvent.php b/app/Events/DockerHubPayloadEvent.php
--- a/app/Events/DockerHubPayloadEvent.php
+++ b/app/Events/DockerHubPayloadEvent.php
@@ -41,10 +41,10 @@
     /**
      * Creates a new event instance.
      *
-     * @param string $door
+     * @param string    $door
      * @param \stdClass $payload
      */
-    public function __construct($door, $payload) {
+    public function __construct(string $door, \stdClass $payload) {
         $this->door = $door;
         $this->payload = $payload;
         $this->event = $this->getEvent();
diff --git a/app/Events/GitHubPayloadEvent.php b/app/Events/GitHubPayloadEvent.php
--- a/app/Events/GitHubPayloadEvent.php
+++ b/app/Events/GitHubPayloadEvent.php
@@ -28,11 +28,11 @@
     /**
      * Creates a new event instance.
      *
-     * @param string $door
-     * @param string $event
+     * @param string    $door
+     * @param string    $event
      * @param \stdClass $payload
      */
-    public function __construct($door, $event, $payload) {
+    public function __construct(string $door, string $event, \stdClass $payload) {
         $this->door = $door;
         $this->event = $event;
         $this->payload = $payload;
diff --git a/app/Events/JenkinsPayloadEvent.php b/app/Events/JenkinsPayloadEvent.php
--- a/app/Events/JenkinsPayloadEvent.php
+++ b/app/Events/JenkinsPayloadEvent.php
@@ -22,10 +22,10 @@
     /**
      * Creates a new event instance.
      *
-     * @param string $door
+     * @param string    $door
      * @param \stdClass $payload
      */
-    public function __construct($door, $payload) {
+    public function __construct(string $door, \stdClass $payload) {
         $this->door = $door;
         $this->payload = $payload;
     }
diff --git a/app/Listeners/LastPayloadSaver.php b/app/Listeners/LastPayloadSaver.php
--- a/app/Listeners/LastPayloadSaver.php
+++ b/app/Listeners/LastPayloadSaver.php
@@ -21,7 +21,7 @@
      *
      * @param mixed $payload The payload to save
      */
-    public static function savePayload ($payload) : void {
+    public static function savePayload (mixed $payload) : void {
         $filename = storage_path('logs/payload.json');
         $content  = json_encode($payload);
         file_put_contents($filename, $content);
diff --git a/app/Notifications/JenkinsNotification.php b/app/Notifications/JenkinsNotification.php
--- a/app/Notifications/JenkinsNotification.php
+++ b/app/Notifications/JenkinsNotification.php
@@ -21,9 +21,9 @@
      * Initializes a new instance of the JenkinsNotification class.
      *
      * @param string $project The project this message is for
-     * @param mixed $payload The message fired by Jenkins notification plugin
+     * @param mixed  $payload The message fired by Jenkins notification plugin
      */
-    public function __construct ($project, $payload) {
+    public function __construct (string $project, mixed $payload) {
         // Straightforward properties
         $this->service = "Jenkins";
         $this->project = $project;
diff --git a/app/Phabricator/PhabricatorAPI.php b/app/Phabricator/PhabricatorAPI.php
--- a/app/Phabricator/PhabricatorAPI.php
+++ b/app/Phabricator/PhabricatorAPI.php
@@ -35,7 +35,7 @@
      * @param string $endPoint The Phabricator main URL, without trailing slash
      * @param string $apiToken The token generated at /settings/panel/apitokens/
      */
-    public function __construct ($endPoint, $apiToken) {
+    public function __construct (string $endPoint, string $apiToken) {
         $this->endPoint = $endPoint;
         $this->apiToken = $apiToken;
     }
@@ -79,18 +79,19 @@
      *
      * @param string $url The API end point URL
      */
-    public function setEndPoint ($url) {
+    public function setEndPoint (string $url) {
         $this->endPoint = $url;
     }
 
     /**
      * Calls a Conduit API method
      *
-     * @param string $method The method to call (e.g. repository.create)
-     * @param array $arguments The arguments to use
+     * @param string $method    The method to call (e.g. repository.create)
+     * @param array  $arguments The arguments to use
+     *
      * @return mixed The API result
      */
-    public function call ($method, $arguments = []) {
+    public function call (string $method, array $arguments = []) {
         $url = $this->endPoint . '/api/' . $method;
         $arguments['api.token'] = $this->apiToken;
 
@@ -114,9 +115,10 @@
      * Gets the first result of an API reply.
      *
      * @param iterable $reply
+     *
      * @return mixed
      */
-    public static function getFirstResult ($reply) {
+    public static function getFirstResult (iterable $reply) {
         if (is_object($reply) && property_exists($reply, 'data')) {
             $reply = $reply->data;
         }
diff --git a/app/Phabricator/PhabricatorAPIFactory.php b/app/Phabricator/PhabricatorAPIFactory.php
--- a/app/Phabricator/PhabricatorAPIFactory.php
+++ b/app/Phabricator/PhabricatorAPIFactory.php
@@ -10,9 +10,10 @@
      * Gets an instance of the Phabricator API client class.
      *
      * @param string $instance The Phabricator instance
+     *
      * @return \Nasqueron\Notifications\Phabricator\PhabricatorAPI
      */
-    public function get ($instance) {
+    public function get (string $instance) {
         return PhabricatorAPI::forInstance($instance);
     }
 
@@ -20,9 +21,10 @@
      * Gets an instance of the Phabricator API client class for a project.
      *
      * @param string $project The Phabricator project name
+     *
      * @return PhabricatorAPI
      */
-    public function getForProject ($project) {
+    public function getForProject (string $project) {
         return PhabricatorAPI::forProject($project);
     }
 }
diff --git a/app/Phabricator/PhabricatorStory.php b/app/Phabricator/PhabricatorStory.php
--- a/app/Phabricator/PhabricatorStory.php
+++ b/app/Phabricator/PhabricatorStory.php
@@ -76,7 +76,7 @@
      *
      * @param string $instanceName The Phabricator instance name
      */
-    public function __construct ($instanceName) {
+    public function __construct (string $instanceName) {
         $this->instanceName = $instanceName;
     }
 
@@ -186,9 +186,10 @@
      * Gets the PHID of a repository
      *
      * @param string $method The API method to call (e.g. differential.query)
+     *
      * @return string The repository PHID or "" if not found
      */
-    public function getRepositoryPHID ($method) {
+    public function getRepositoryPHID (string $method) {
         $objectPHID = $this->data['objectPHID'];
 
         $api = PhabricatorAPI::forProject($this->instanceName);
@@ -216,11 +217,12 @@
     /**
      * Gets the projects for a specific item
      *
-     * @param string $method The API method to call (e.g. differential.query)
+     * @param string $method     The API method to call (e.g. differential.query)
      * @param string $objectPHID The object PHID to pass as method parameter
+     *
      * @return string[] The list of project PHIDs
      */
-    public function getItemProjectsPHIDs ($method, $objectPHID) {
+    public function getItemProjectsPHIDs (string $method, string $objectPHID) {
         if (!$objectPHID) {
             return [];
         }
@@ -314,9 +316,10 @@
      * Maps a field of the API reply to a property of the PhabricatorStory class
      *
      * @param string $key The field of the API reply
+     *
      * @return string The property's name
      */
-    public static function mapPhabricatorFeedKey ($key) {
+    public static function mapPhabricatorFeedKey (string $key) {
         if ($key == "storyID") {
             return "id";
         }
diff --git a/app/Phabricator/ProjectsMap.php b/app/Phabricator/ProjectsMap.php
--- a/app/Phabricator/ProjectsMap.php
+++ b/app/Phabricator/ProjectsMap.php
@@ -54,7 +54,7 @@
      *
      * @param string $instanceName The Phabricator instance name
      */
-    public function __construct ($instanceName) {
+    public function __construct (string $instanceName) {
         $this->instanceName = $instanceName;
     }
 
@@ -81,7 +81,7 @@
      * @param mixed $offset The offset
      * @return bool
      */
-    public function offsetExists ($offset) {
+    public function offsetExists (mixed $offset) {
         return array_key_exists($offset, $this->map);
     }
 
@@ -91,7 +91,7 @@
      * @param mixed $offset The offset.
      * @return mixed The value
      */
-    public function offsetGet ($offset) {
+    public function offsetGet (mixed $offset) {
         return $this->map[$offset];
     }
 
@@ -101,7 +101,7 @@
      * @param mixed $offset The offset
      * @param mixed $value The value to assign
      */
-    public function offsetSet ($offset, $value) {
+    public function offsetSet (mixed $offset, mixed $value) {
         $this->map[$offset] = $value;
     }
 
@@ -110,7 +110,7 @@
      *
      * @param mixed $offset The offset where to remove the value
      */
-    public function offsetUnset ($offset) {
+    public function offsetUnset (mixed $offset) {
         unset($this->map[$offset]);
     }
 
@@ -122,9 +122,10 @@
      * Gets a new ProjectsMap instance from cache or API when not cached.
      *
      * @param string $phabricatorInstanceName The Phabricator instance name
+     *
      * @return ProjectsMap
      */
-    public static function load ($phabricatorInstanceName) {
+    public static function load (string $phabricatorInstanceName) {
         $instance = new self($phabricatorInstanceName);
 
         if ($instance->isCached()) {
@@ -255,9 +256,10 @@
      * Gets project name, refreshing the cache if needed.
      *
      * @param string $projectPHID the PHID of the project to query the name
+     *
      * @return string The name of the poject, or an empty string if not found
      */
-    public function getProjectName ($projectPHID) {
+    public function getProjectName (string $projectPHID) {
         if ($this->offsetExists($projectPHID)) {
             return $this->offsetGet($projectPHID);
         }