diff --git a/src/GeneralOptions/Base.php b/src/GeneralOptions/Base.php
index d23f0232..f793b6ff 100644
--- a/src/GeneralOptions/Base.php
+++ b/src/GeneralOptions/Base.php
@@ -42,7 +42,7 @@ abstract class Base implements Controllable {
 	 *
 	 * @return string
 	 */
-	public static function get_slug() {
+	public static function get_slug(): string {
 		return static::$slug;
 	}
 
@@ -75,7 +75,7 @@ public static function init() {
 	 * @return array Updated options.
 	 * @since 3.0.0
 	 */
-	public static function add_general_option( $options ) {
+	public static function add_general_option( array $options ): array {
 		$options[] = static::class;
 
 		return $options;
@@ -88,7 +88,7 @@ public static function add_general_option( $options ) {
 	 *
 	 * @return mixed|null
 	 */
-	public static function is_active( $type = 'general' ) {
+	public static function is_active( string $type = 'general' ) {
 		return Settings::get_option( static::get_option_name( 'active' ), $type );
 	}
 
@@ -98,7 +98,7 @@ public static function is_active( $type = 'general' ) {
 	 *
 	 * @return bool
 	 */
-	public static function only_print_custom_options() {
+	public static function only_print_custom_options(): bool {
 		return static::$only_custom_options;
 	}
 
@@ -107,7 +107,7 @@ public static function only_print_custom_options() {
 	 *
 	 * @return string[]
 	 */
-	public static function get_supported_types() {
+	public static function get_supported_types(): array {
 		return [ 'general' ];
 	}
 
@@ -116,7 +116,7 @@ public static function get_supported_types() {
 	 *
 	 * @return string
 	 */
-	public static function get_type() {
+	public static function get_type(): string {
 		return static::$type;
 	}
 
@@ -127,7 +127,7 @@ public static function get_type() {
 	 * @param string $name Name suffix.
 	 * @return string Corresponding option name
 	 */
-	public static function get_option_name( $name ) {
+	public static function get_option_name( string $name ): string {
 		$type        = static::get_type();
 		$slug        = static::get_slug();
 		$option_name = "{$type}_{$slug}_{$name}";
diff --git a/src/GeneralOptions/DeleteOldSpam.php b/src/GeneralOptions/DeleteOldSpam.php
index 2696aab2..3f5ffbb5 100644
--- a/src/GeneralOptions/DeleteOldSpam.php
+++ b/src/GeneralOptions/DeleteOldSpam.php
@@ -27,7 +27,7 @@ class DeleteOldSpam extends Base {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Delete old spam', 'antispam-bee' );
 	}
 
@@ -56,7 +56,7 @@ public static function get_description() {
 	 *
 	 * @return array
 	 */
-	public static function get_options() {
+	public static function get_options(): array {
 		return [
 			[
 				'type'        => 'inline',
diff --git a/src/GeneralOptions/IgnoreLinkbacks.php b/src/GeneralOptions/IgnoreLinkbacks.php
index e0370975..0556059b 100644
--- a/src/GeneralOptions/IgnoreLinkbacks.php
+++ b/src/GeneralOptions/IgnoreLinkbacks.php
@@ -24,7 +24,7 @@ class IgnoreLinkbacks extends Base {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Linkbacks', 'antispam-bee' );
 	}
 
diff --git a/src/GeneralOptions/Statistics.php b/src/GeneralOptions/Statistics.php
index 93411393..b3e27d9a 100644
--- a/src/GeneralOptions/Statistics.php
+++ b/src/GeneralOptions/Statistics.php
@@ -24,7 +24,7 @@ class Statistics extends Base {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Statistics', 'antispam-bee' );
 	}
 
diff --git a/src/GeneralOptions/Uninstall.php b/src/GeneralOptions/Uninstall.php
index 460c9124..addffe6c 100644
--- a/src/GeneralOptions/Uninstall.php
+++ b/src/GeneralOptions/Uninstall.php
@@ -24,7 +24,7 @@ class Uninstall extends Base {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Uninstall', 'antispam-bee' );
 	}
 
diff --git a/src/Interfaces/Controllable.php b/src/Interfaces/Controllable.php
index e36912a4..7841707a 100644
--- a/src/Interfaces/Controllable.php
+++ b/src/Interfaces/Controllable.php
@@ -18,7 +18,7 @@ interface Controllable {
 	 *
 	 * @return string
 	 */
-	public static function get_name();
+	public static function get_name(): string;
 
 	/**
 	 * Get element label (optional).
@@ -54,7 +54,7 @@ public static function get_description();
 	 *   ]
 	 * ]
 	 *
-	 * @return mixed
+	 * @return array|null
 	 */
 	public static function get_options();
 
@@ -66,7 +66,7 @@ public static function get_options();
 	 *
 	 * @return mixed|null
 	 */
-	public static function is_active( $type );
+	public static function is_active( string $type );
 
 	/**
 	 * Only print custom options?
@@ -74,28 +74,28 @@ public static function is_active( $type );
 	 *
 	 * @return bool
 	 */
-	public static function only_print_custom_options();
+	public static function only_print_custom_options(): bool;
 
 	/**
 	 * Get a list of supported types.
 	 *
 	 * @return string[]
 	 */
-	public static function get_supported_types();
+	public static function get_supported_types(): array;
 
 	/**
 	 * Get type of the controllable.
 	 *
 	 * @return string
 	 */
-	public static function get_type();
+	public static function get_type(): string;
 
 	/**
 	 * Get controllable slug.
 	 *
 	 * @return string
 	 */
-	public static function get_slug();
+	public static function get_slug(): string;
 
 	/**
 	 * Get option name.
@@ -104,5 +104,5 @@ public static function get_slug();
 	 * @param string $name Name suffix.
 	 * @return string Corresponding option name
 	 */
-	public static function get_option_name( $name );
+	public static function get_option_name( string $name ): string;
 }
diff --git a/src/Interfaces/PostProcessor.php b/src/Interfaces/PostProcessor.php
index 4848b132..22490b80 100644
--- a/src/Interfaces/PostProcessor.php
+++ b/src/Interfaces/PostProcessor.php
@@ -15,26 +15,26 @@ interface PostProcessor {
 	 * @param array $item Item to process.
 	 * @return array Processed item.
 	 */
-	public static function process( $item );
+	public static function process( array $item ): array;
 
 	/**
 	 * Get post processor slug.
 	 *
 	 * @return string The slug.
 	 */
-	public static function get_slug();
+	public static function get_slug(): string;
 
 	/**
 	 * Get a list of supported types.
 	 *
 	 * @return string[]
 	 */
-	public static function get_supported_types();
+	public static function get_supported_types(): array;
 
 	/**
 	 * Does this processor mark am element as deleted?
 	 *
 	 * @return bool
 	 */
-	public static function marks_as_delete();
+	public static function marks_as_delete(): bool;
 }
diff --git a/src/Interfaces/SpamReason.php b/src/Interfaces/SpamReason.php
index a52c170f..e78330c6 100644
--- a/src/Interfaces/SpamReason.php
+++ b/src/Interfaces/SpamReason.php
@@ -17,5 +17,5 @@ interface SpamReason {
 	 *
 	 * @return string
 	 */
-	public static function get_reason_text();
+	public static function get_reason_text(): string;
 }
diff --git a/src/Interfaces/Verifiable.php b/src/Interfaces/Verifiable.php
index 4eb5465b..36da7683 100644
--- a/src/Interfaces/Verifiable.php
+++ b/src/Interfaces/Verifiable.php
@@ -18,7 +18,7 @@ interface Verifiable {
 	 * @param array $item Item to verify.
 	 * @return int Weighted result.
 	 */
-	public static function verify( $item );
+	public static function verify( array $item ): int;
 
 	/**
 	 * Get rule weight.
@@ -26,26 +26,26 @@ public static function verify( $item );
 	 *
 	 * @return int Weight factor.
 	 */
-	public static function get_weight();
+	public static function get_weight(): int;
 
 	/**
 	 * Get element slug.
 	 *
 	 * @return string The slug.
 	 */
-	public static function get_slug();
+	public static function get_slug(): string;
 
 	/**
 	 * Get a list of supported types.
 	 *
 	 * @return string[]
 	 */
-	public static function get_supported_types();
+	public static function get_supported_types(): array;
 
 	/**
 	 * It this rule final?
 	 *
 	 * @return bool
 	 */
-	public static function is_final();
+	public static function is_final(): bool;
 }
diff --git a/src/PostProcessors/Base.php b/src/PostProcessors/Base.php
index d2eaff15..f05e5f75 100644
--- a/src/PostProcessors/Base.php
+++ b/src/PostProcessors/Base.php
@@ -52,7 +52,7 @@ public static function init() {
 	 *
 	 * @return PostProcessor[] Updated list of post processors.
 	 */
-	public static function add_post_processor( $post_processors ) {
+	public static function add_post_processor( array $post_processors ): array {
 		$post_processors[] = static::class;
 
 		return $post_processors;
@@ -63,7 +63,7 @@ public static function add_post_processor( $post_processors ) {
 	 *
 	 * @return string The slug.
 	 */
-	public static function get_slug() {
+	public static function get_slug(): string {
 		return static::$slug;
 	}
 
@@ -72,7 +72,7 @@ public static function get_slug() {
 	 *
 	 * @return string[]
 	 */
-	public static function get_supported_types() {
+	public static function get_supported_types(): array {
 		// @todo: add filter
 		return static::$supported_types;
 	}
@@ -82,7 +82,7 @@ public static function get_supported_types() {
 	 *
 	 * @return bool
 	 */
-	public static function marks_as_delete() {
+	public static function marks_as_delete(): bool {
 		return static::$marks_as_delete;
 	}
 }
diff --git a/src/PostProcessors/ControllableBase.php b/src/PostProcessors/ControllableBase.php
index 159ddfde..83f66e43 100644
--- a/src/PostProcessors/ControllableBase.php
+++ b/src/PostProcessors/ControllableBase.php
@@ -35,7 +35,7 @@ abstract class ControllableBase extends Base implements Controllable {
 	 *
 	 * @return mixed|null
 	 */
-	public static function is_active( $type ) {
+	public static function is_active( string $type ) {
 		return Settings::get_option( static::get_option_name( 'active' ), $type );
 	}
 
@@ -56,7 +56,7 @@ public static function get_options() {
 	 *
 	 * @return bool
 	 */
-	public static function only_print_custom_options() {
+	public static function only_print_custom_options(): bool {
 		return static::$only_print_custom_options;
 	}
 
@@ -65,7 +65,7 @@ public static function only_print_custom_options() {
 	 *
 	 * @return string
 	 */
-	public static function get_type() {
+	public static function get_type(): string {
 		return static::$type;
 	}
 
@@ -76,7 +76,7 @@ public static function get_type() {
 	 * @param string $name Name suffix.
 	 * @return string Corresponding option name
 	 */
-	public static function get_option_name( $name ) {
+	public static function get_option_name( string $name ): string {
 		$type        = static::get_type();
 		$slug        = static::get_slug();
 		$option_name = "{$type}_{$slug}_{$name}";
diff --git a/src/PostProcessors/Delete.php b/src/PostProcessors/Delete.php
index 18fd07dd..a38975a6 100644
--- a/src/PostProcessors/Delete.php
+++ b/src/PostProcessors/Delete.php
@@ -32,7 +32,7 @@ class Delete extends ControllableBase {
 	 * @param array $item Item to process.
 	 * @return array Processed item.
 	 */
-	public static function process( $item ) {
+	public static function process( array $item ): array {
 		$item['asb_marked_as_delete'] = true;
 
 		return $item;
@@ -43,7 +43,7 @@ public static function process( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Delete spam', 'antispam-bee' );
 	}
 
diff --git a/src/PostProcessors/DeleteForReasons.php b/src/PostProcessors/DeleteForReasons.php
index 225b0af6..c4bb0faf 100644
--- a/src/PostProcessors/DeleteForReasons.php
+++ b/src/PostProcessors/DeleteForReasons.php
@@ -36,7 +36,7 @@ class DeleteForReasons extends ControllableBase {
 	 * @param array $item Item to process.
 	 * @return array Processed item.
 	 */
-	public static function process( $item ) {
+	public static function process( array $item ): array {
 		if ( isset( $item['asb_marked_as_delete'] ) && true === $item['asb_marked_as_delete'] ) {
 			return $item;
 		}
@@ -58,7 +58,7 @@ public static function process( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Delete by reasons', 'antispam-bee' );
 	}
 
diff --git a/src/PostProcessors/SaveReason.php b/src/PostProcessors/SaveReason.php
index d95ce980..2b9c4288 100644
--- a/src/PostProcessors/SaveReason.php
+++ b/src/PostProcessors/SaveReason.php
@@ -26,7 +26,7 @@ class SaveReason extends ControllableBase {
 	 * @param array $item Item to process.
 	 * @return array Processed item.
 	 */
-	public static function process( $item ) {
+	public static function process( array $item ): array {
 		if ( isset( $item['asb_marked_as_delete'] ) && true === $item['asb_marked_as_delete'] ) {
 			return $item;
 		}
@@ -55,7 +55,7 @@ function ( $comment_id ) use ( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Save reasons', 'antispam-bee' );
 	}
 
diff --git a/src/PostProcessors/SendEmail.php b/src/PostProcessors/SendEmail.php
index 25934db6..34267a25 100644
--- a/src/PostProcessors/SendEmail.php
+++ b/src/PostProcessors/SendEmail.php
@@ -29,7 +29,7 @@ class SendEmail extends ControllableBase {
 	 * @param array $item Item to process.
 	 * @return array Processed item.
 	 */
-	public static function process( $item ) {
+	public static function process( array $item ): array {
 		if ( isset( $item['asb_marked_as_delete'] ) && true === $item['asb_marked_as_delete'] ) {
 			return $item;
 		}
@@ -85,7 +85,7 @@ function ( $id ) use ( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Send email', 'antispam-bee' );
 	}
 
diff --git a/src/PostProcessors/UpdateSpamCount.php b/src/PostProcessors/UpdateSpamCount.php
index 1d800efb..a1cd24cc 100644
--- a/src/PostProcessors/UpdateSpamCount.php
+++ b/src/PostProcessors/UpdateSpamCount.php
@@ -29,7 +29,7 @@ class UpdateSpamCount extends Base {
 	 * @param array $item Item to process.
 	 * @return array Processed item.
 	 */
-	public static function process( $item ) {
+	public static function process( array $item ): array {
 		if ( ! Statistics::is_active() ) {
 			return $item;
 		}
diff --git a/src/PostProcessors/UpdateSpamLog.php b/src/PostProcessors/UpdateSpamLog.php
index 6048ff9f..b2204c8c 100644
--- a/src/PostProcessors/UpdateSpamLog.php
+++ b/src/PostProcessors/UpdateSpamLog.php
@@ -26,7 +26,7 @@ class UpdateSpamLog extends Base {
 	 * @param array $item Item to process.
 	 * @return array Processed item.
 	 */
-	public static function process( $item ) {
+	public static function process( array $item ): array {
 		if ( ! isset( $item['comment_post_ID'] ) || ! isset( $item['comment_author_IP'] ) ) {
 			$item['asb_post_processors_failed'][] = self::get_slug();
 			return $item;
diff --git a/src/Rules/ApprovedEmail.php b/src/Rules/ApprovedEmail.php
index f733c43c..f248677b 100644
--- a/src/Rules/ApprovedEmail.php
+++ b/src/Rules/ApprovedEmail.php
@@ -37,7 +37,7 @@ class ApprovedEmail extends ControllableBase {
 	 * @param array $item Item to verify.
 	 * @return int Numeric result.
 	 */
-	public static function verify( $item ) {
+	public static function verify( array $item ): int {
 		$email = DataHelper::get_values_where_key_contains( [ 'email' ], $item );
 		if ( empty( $email ) ) {
 			return 0;
@@ -65,7 +65,7 @@ public static function verify( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Approved Email', 'antispam-bee' );
 	}
 
diff --git a/src/Rules/BBCode.php b/src/Rules/BBCode.php
index 921d086c..1f34ef87 100644
--- a/src/Rules/BBCode.php
+++ b/src/Rules/BBCode.php
@@ -29,7 +29,7 @@ class BBCode extends ControllableBase implements SpamReason {
 	 * @param array $item Item to verify.
 	 * @return int Numeric result.
 	 */
-	public static function verify( $item ) {
+	public static function verify( array $item ): int {
 		foreach ( $item as $value ) {
 			if ( true === (bool) preg_match( '/\[url[=\]].*\[\/url\]/is', $value ) ) {
 				return 1;
@@ -44,7 +44,7 @@ public static function verify( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return _x( 'BBCode', 'spam-reason-form-name', 'antispam-bee' );
 	}
 
@@ -71,7 +71,7 @@ public static function get_description() {
 	 *
 	 * @return string
 	 */
-	public static function get_reason_text() {
+	public static function get_reason_text(): string {
 		return _x( 'BBCode', 'spam-reason-text', 'antispam-bee' );
 	}
 }
diff --git a/src/Rules/Base.php b/src/Rules/Base.php
index b6d8206f..46ab48cc 100644
--- a/src/Rules/Base.php
+++ b/src/Rules/Base.php
@@ -68,7 +68,7 @@ public static function init() {
 	 *
 	 * @return array
 	 */
-	public static function add_rule( $rules ) {
+	public static function add_rule( array $rules ): array {
 		$rules[] = static::class;
 
 		return $rules;
@@ -79,7 +79,7 @@ public static function add_rule( $rules ) {
 	 *
 	 * @return array
 	 */
-	public static function get_supported_types() {
+	public static function get_supported_types(): array {
 		/**
 		 * Filter the reaction types that are supported by the rule.
 		 *
@@ -97,7 +97,7 @@ public static function get_supported_types() {
 	 *
 	 * @return int Weight factor.
 	 */
-	public static function get_weight() {
+	public static function get_weight(): int {
 		return static::$weight;
 	}
 
@@ -106,7 +106,7 @@ public static function get_weight() {
 	 *
 	 * @return string The slug.
 	 */
-	public static function get_slug() {
+	public static function get_slug(): string {
 		return static::$slug;
 	}
 
@@ -115,7 +115,7 @@ public static function get_slug() {
 	 *
 	 * @return bool
 	 */
-	public static function is_final() {
+	public static function is_final(): bool {
 		return static::$is_final;
 	}
 
@@ -124,7 +124,7 @@ public static function is_final() {
 	 *
 	 * @return bool
 	 */
-	public static function is_invisible() {
+	public static function is_invisible(): bool {
 		return static::$is_invisible;
 	}
 }
diff --git a/src/Rules/ControllableBase.php b/src/Rules/ControllableBase.php
index f36c0321..cc52f2c0 100644
--- a/src/Rules/ControllableBase.php
+++ b/src/Rules/ControllableBase.php
@@ -36,7 +36,7 @@ abstract class ControllableBase extends Base implements Controllable {
 	 *
 	 * @return mixed|null
 	 */
-	public static function is_active( $type ) {
+	public static function is_active( string $type ) {
 		return Settings::get_option( static::get_option_name( 'active' ), $type );
 	}
 
@@ -57,7 +57,7 @@ public static function get_options() {
 	 *
 	 * @return bool
 	 */
-	public static function only_print_custom_options() {
+	public static function only_print_custom_options(): bool {
 		return static::$only_print_custom_options;
 	}
 
@@ -66,7 +66,7 @@ public static function only_print_custom_options() {
 	 *
 	 * @return string
 	 */
-	public static function get_type() {
+	public static function get_type(): string {
 		return static::$type;
 	}
 
@@ -77,7 +77,7 @@ public static function get_type() {
 	 * @param string $name Name suffix.
 	 * @return string Corresponding option name
 	 */
-	public static function get_option_name( $name ) {
+	public static function get_option_name( string $name ): string {
 		$type        = static::get_type();
 		$slug        = static::get_slug();
 		$option_name = "{$type}_{$slug}_{$name}";
diff --git a/src/Rules/CountrySpam.php b/src/Rules/CountrySpam.php
index 2ea973df..39f7203c 100644
--- a/src/Rules/CountrySpam.php
+++ b/src/Rules/CountrySpam.php
@@ -32,7 +32,7 @@ class CountrySpam extends ControllableBase implements SpamReason {
 	 * @param array $item Item to verify.
 	 * @return int Numeric result.
 	 */
-	public static function verify( $item ) {
+	public static function verify( array $item ): int {
 		if ( ! isset( $item['comment_author_IP'] ) || empty( $item['comment_author_IP'] ) ) {
 			return 0;
 		}
@@ -137,7 +137,7 @@ public static function verify( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Country Check', 'antispam-bee' );
 	}
 
@@ -248,7 +248,7 @@ private static function sanitize_iso_codes_string( $value ) {
 	 *
 	 * @return string
 	 */
-	public static function get_reason_text() {
+	public static function get_reason_text(): string {
 		return __( 'Country', 'antispam-bee' );
 	}
 }
diff --git a/src/Rules/DbSpam.php b/src/Rules/DbSpam.php
index 3f53f0c5..f4e9d7e9 100644
--- a/src/Rules/DbSpam.php
+++ b/src/Rules/DbSpam.php
@@ -30,7 +30,7 @@ class DbSpam extends ControllableBase implements SpamReason {
 	 * @param array $item Item to verify.
 	 * @return int Numeric result.
 	 */
-	public static function verify( $item ) {
+	public static function verify( array $item ): int {
 		$params = [];
 		$filter = [];
 		$url    = wp_unslash( array_shift( DataHelper::get_values_where_key_contains( [ 'url' ], $item ) ) );
@@ -83,7 +83,7 @@ public static function verify( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Local DB Spam', 'antispam-bee' );
 	}
 
@@ -110,7 +110,7 @@ public static function get_description() {
 	 *
 	 * @return string
 	 */
-	public static function get_reason_text() {
+	public static function get_reason_text(): string {
 		return __( 'Local DB', 'antispam-bee' );
 	}
 }
diff --git a/src/Rules/EmptyData.php b/src/Rules/EmptyData.php
index add1ffc3..f6f26944 100644
--- a/src/Rules/EmptyData.php
+++ b/src/Rules/EmptyData.php
@@ -30,7 +30,7 @@ class EmptyData extends Base implements SpamReason {
 	 * @param array $item Item to verify.
 	 * @return int Numeric result.
 	 */
-	public static function verify( $item ) {
+	public static function verify( array $item ): int {
 		// phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound
 		$allow_empty_reaction = apply_filters( 'allow_empty_comment', false, $item );
 		$content              = $item['comment_content'] ?? '';
@@ -63,7 +63,7 @@ public static function verify( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return _x( 'Empty Data', 'spam-reason-form-name', 'antispam-bee' );
 	}
 
@@ -72,7 +72,7 @@ public static function get_name() {
 	 *
 	 * @return string
 	 */
-	public static function get_reason_text() {
+	public static function get_reason_text(): string {
 		return _x( 'Empty Data', 'spam-reason-text', 'antispam-bee' );
 	}
 }
diff --git a/src/Rules/Honeypot.php b/src/Rules/Honeypot.php
index 0c793e36..0c58088f 100644
--- a/src/Rules/Honeypot.php
+++ b/src/Rules/Honeypot.php
@@ -61,7 +61,7 @@ function ( $field_markup ) {
 	 * @param array $item Item to verify.
 	 * @return int Numeric result.
 	 */
-	public static function verify( $item ) {
+	public static function verify( array $item ): int {
 		// phpcs:ignore WordPress.Security.NonceVerification.Missing
 		if ( isset( $_POST['ab_spam__hidden_field'] ) && 1 === $_POST['ab_spam__hidden_field'] ) {
 			return 999;
@@ -120,7 +120,7 @@ public static function precheck() {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return _x( 'Honeypot', 'spam-reason-form-name', 'antispam-bee' );
 	}
 
@@ -147,7 +147,7 @@ public static function get_description() {
 	 *
 	 * @return string
 	 */
-	public static function get_reason_text() {
+	public static function get_reason_text(): string {
 		return _x( 'Honeypot', 'spam-reason-text', 'antispam-bee' );
 	}
 }
diff --git a/src/Rules/InvalidRequest.php b/src/Rules/InvalidRequest.php
index 153c62ef..4f1f20e6 100644
--- a/src/Rules/InvalidRequest.php
+++ b/src/Rules/InvalidRequest.php
@@ -29,7 +29,7 @@ class InvalidRequest extends Base implements SpamReason {
 	 * @param array $item Item to verify.
 	 * @return int Numeric result.
 	 */
-	public static function verify( $item ) {
+	public static function verify( array $item ): int {
 		// phpcs:ignore WordPress.Security.NonceVerification.Missing,WordPress.Security.ValidatedSanitizedInput
 		if ( isset( $_POST['ab_spam__invalid_request'] ) && $_POST['ab_spam__invalid_request'] ) {
 			return 999;
@@ -43,7 +43,7 @@ public static function verify( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return _x( 'Invalid Request', 'spam-reason-form-name', 'antispam-bee' );
 	}
 
@@ -52,7 +52,7 @@ public static function get_name() {
 	 *
 	 * @return string
 	 */
-	public static function get_reason_text() {
+	public static function get_reason_text(): string {
 		return _x( 'Invalid Request', 'spam-reason-text', 'antispam-bee' );
 	}
 }
diff --git a/src/Rules/LangSpam.php b/src/Rules/LangSpam.php
index 443b3b22..b164b909 100644
--- a/src/Rules/LangSpam.php
+++ b/src/Rules/LangSpam.php
@@ -33,7 +33,7 @@ class LangSpam extends ControllableBase implements SpamReason {
 	 * @param array $item Item to verify.
 	 * @return int Numeric result.
 	 */
-	public static function verify( $item ) {
+	public static function verify( array $item ): int {
 		$allowed_languages = array_keys( (array) Settings::get_option( static::get_option_name( 'allowed' ), $item['reaction_type'] ) );
 
 		$comment_content = DataHelper::get_values_where_key_contains( [ 'content' ], $item );
@@ -118,7 +118,7 @@ public static function verify( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Language', 'antispam-bee' );
 	}
 
@@ -199,7 +199,7 @@ public static function get_options() {
 	 *
 	 * @return string
 	 */
-	public static function get_reason_text() {
+	public static function get_reason_text(): string {
 		return __( 'Language', 'antispam-bee' );
 	}
 }
diff --git a/src/Rules/LinkbackFromMyself.php b/src/Rules/LinkbackFromMyself.php
index 0f636a2c..3fe13b2b 100644
--- a/src/Rules/LinkbackFromMyself.php
+++ b/src/Rules/LinkbackFromMyself.php
@@ -46,7 +46,7 @@ class LinkbackFromMyself extends Base implements SpamReason {
 	 * @param array $item Item to verify.
 	 * @return int Numeric result.
 	 */
-	public static function verify( $item ) {
+	public static function verify( array $item ): int {
 		$url            = isset( $item['comment_author_url'] ) ? $item['comment_author_url'] : null;
 		$target_post_id = isset( $item['comment_post_ID'] ) ? $item['comment_post_ID'] : null;
 		if ( empty( $url ) || empty( $target_post_id ) ) {
@@ -88,7 +88,7 @@ public static function verify( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Linkback from myself', 'antispam-bee' );
 	}
 
@@ -97,7 +97,7 @@ public static function get_name() {
 	 *
 	 * @return string
 	 */
-	public static function get_reason_text() {
+	public static function get_reason_text(): string {
 		return _x( 'Linkback from myself', 'spam-reason-text', 'antispam-bee' );
 	}
 }
diff --git a/src/Rules/LinkbackPostTitleIsBlogName.php b/src/Rules/LinkbackPostTitleIsBlogName.php
index f18d90d9..633d6439 100644
--- a/src/Rules/LinkbackPostTitleIsBlogName.php
+++ b/src/Rules/LinkbackPostTitleIsBlogName.php
@@ -37,7 +37,7 @@ class LinkbackPostTitleIsBlogName extends Base implements SpamReason {
 	 * @param array $item Item to verify.
 	 * @return int Numeric result.
 	 */
-	public static function verify( $item ) {
+	public static function verify( array $item ): int {
 		$body      = isset( $item['comment_content'] ) ? $item['comment_content'] : null;
 		$blog_name = isset( $item['comment_author'] ) ? $item['comment_author'] : null;
 		preg_match( '/<strong>(.*)<\/strong>\\n\\n/', $body, $matches );
@@ -53,7 +53,7 @@ public static function verify( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Linkback post title is blog name', 'antispam-bee' );
 	}
 
@@ -62,7 +62,7 @@ public static function get_name() {
 	 *
 	 * @return string
 	 */
-	public static function get_reason_text() {
+	public static function get_reason_text(): string {
 		return _x( 'Linkback Post Title', 'spam-reason-text', 'antispam-bee' );
 	}
 }
diff --git a/src/Rules/RegexpSpam.php b/src/Rules/RegexpSpam.php
index e24d49ce..07cca24a 100644
--- a/src/Rules/RegexpSpam.php
+++ b/src/Rules/RegexpSpam.php
@@ -32,7 +32,7 @@ class RegexpSpam extends ControllableBase implements SpamReason {
 	 * @param array $item Item to verify.
 	 * @return int Numeric result.
 	 */
-	public static function verify( $item ) {
+	public static function verify( array $item ): int {
 		$fields = [
 			'ip',
 			'host',
@@ -178,7 +178,7 @@ public static function verify( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Regular Expression', 'antispam-bee' );
 	}
 
@@ -205,7 +205,7 @@ public static function get_description() {
 	 *
 	 * @return string
 	 */
-	public static function get_reason_text() {
+	public static function get_reason_text(): string {
 		return _x( 'RegExp match', 'spam-reason-text', 'antispam-bee' );
 	}
 }
diff --git a/src/Rules/TooFastSubmit.php b/src/Rules/TooFastSubmit.php
index 31587210..cea9f6f1 100644
--- a/src/Rules/TooFastSubmit.php
+++ b/src/Rules/TooFastSubmit.php
@@ -75,7 +75,7 @@ function ( $field_markup ) {
 	 * @param array $item Item to verify.
 	 * @return int Numeric result.
 	 */
-	public static function verify( $item ) {
+	public static function verify( array $item ): int {
 		// phpcs:disable WordPress.Security.NonceVerification.Missing
 		// Everybody can Post.
 		if ( ! isset( $_POST['ab_init_time'] ) ) {
@@ -100,7 +100,7 @@ public static function verify( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Comment time', 'antispam-bee' );
 	}
 
@@ -127,7 +127,7 @@ public static function get_description() {
 	 *
 	 * @return string
 	 */
-	public static function get_reason_text() {
+	public static function get_reason_text(): string {
 		return _x( 'Created too quickly', 'spam-reason-text', 'antispam-bee' );
 	}
 }
diff --git a/src/Rules/ValidGravatar.php b/src/Rules/ValidGravatar.php
index 62bd7f9e..b06b5c0b 100644
--- a/src/Rules/ValidGravatar.php
+++ b/src/Rules/ValidGravatar.php
@@ -37,7 +37,7 @@ class ValidGravatar extends ControllableBase {
 	 * @param array $item Item to verify.
 	 * @return int Numeric result.
 	 */
-	public static function verify( $item ) {
+	public static function verify( array $item ): int {
 		$email = DataHelper::get_values_where_key_contains( [ 'email' ], $item );
 		if ( empty( $email ) ) {
 			return 0;
@@ -67,7 +67,7 @@ public static function verify( $item ) {
 	 *
 	 * @return string
 	 */
-	public static function get_name() {
+	public static function get_name(): string {
 		return __( 'Valid Gravatar', 'antispam-bee' );
 	}