diff --git a/composer.json b/composer.json
index 38a8d8870..d749ca2bf 100644
--- a/composer.json
+++ b/composer.json
@@ -10,7 +10,8 @@
     ],
     "require": {
         "cleantalk/spbct-heuristic-analyser": "*",
-        "cleantalk/spbct-signatures-analyser": "*"
+        "cleantalk/spbct-signatures-analyser": "*",
+        "cleantalk/spbct-helpers": "*"
     },
     "require-dev": {
         "vimeo/psalm": "^4.8",
diff --git a/inc/spbc-admin.php b/inc/spbc-admin.php
index 919a5bee3..b4acd0cf0 100644
--- a/inc/spbc-admin.php
+++ b/inc/spbc-admin.php
@@ -7,6 +7,7 @@
 use CleantalkSP\SpbctWP\Escape;
 use CleantalkSP\SpbctWP\Scanner\DBTrigger\DBTriggerService;
 use CleantalkSP\SpbctWP\Settings\SettingsGeneralReact;
+use CleantalkSP\SpbctWP\SpbcDevLogger;
 use CleantalkSP\SpbctWP\VulnerabilityAlarm\Dto\PluginReport;
 use CleantalkSP\SpbctWP\Firewall\View as FirewallView;
 use CleantalkSP\SpbctWP\VulnerabilityAlarm\Dto\ThemeReport;
@@ -604,7 +605,7 @@ function spbc_admin_log_action()
         try {
             spbc_write_timer($secure_cookies);
         } catch (Exception $e) {
-            error_log($e->getMessage());
+            SpbcDevLogger::write($e->getMessage());
         }
     }
 
@@ -631,7 +632,7 @@ function spbc_admin_log_action()
         try {
             spbc_set_secure_cookies($cookies_arr);
         } catch (Exception $e) {
-            error_log($e->getMessage());
+            SpbcDevLogger::write($e->getMessage());
         }
     }
 
diff --git a/inc/spbc-settings.php b/inc/spbc-settings.php
index e848cca07..f0478e7f5 100644
--- a/inc/spbc-settings.php
+++ b/inc/spbc-settings.php
@@ -3980,6 +3980,15 @@ function spbc_field_debug()
         $output = print_r($debug, true);
         $output = str_replace("\n", "<br>", $output);
         $output = preg_replace("/[^\S]{4}/", "&nbsp;&nbsp;&nbsp;&nbsp;", $output);
+        $spbc->dev_log; // This is the lazy load the `dev_log` property into the State
+        if ( ! empty($spbc->dev_log) ) {
+            echo 'Dev log:' . "<br>";
+            $dev_log  = $spbc->dev_log;
+            $dev_log_output = print_r($dev_log, true);
+            $dev_log_output = str_replace("\n", "<br>", $dev_log_output);
+            $dev_log_output = preg_replace("/[^\S]{4}/", "&nbsp;&nbsp;&nbsp;&nbsp;", $dev_log_output);
+            $output .= $dev_log_output;
+        }
         echo "<div class='spbc_wrapper_field'>";
         echo $output
              . "<label for=''>" .
diff --git a/lib/CleantalkSP/Common/EarlyTranslation.php b/lib/CleantalkSP/Common/EarlyTranslation.php
index d8106de6e..56a8bc242 100644
--- a/lib/CleantalkSP/Common/EarlyTranslation.php
+++ b/lib/CleantalkSP/Common/EarlyTranslation.php
@@ -444,6 +444,7 @@ public function checkWPTranslationReady()
     protected function echoError($error)
     {
         if (is_string($error) && $this->error_tracking_level >= 1 && function_exists('error_log') ) {
+            /** @psalm-suppress ForbiddenCode */
             error_log($error);
         }
     }
diff --git a/lib/CleantalkSP/Common/Enqueue/Enqueue.php b/lib/CleantalkSP/Common/Enqueue/Enqueue.php
index 3f07959e5..e3a4b57f4 100644
--- a/lib/CleantalkSP/Common/Enqueue/Enqueue.php
+++ b/lib/CleantalkSP/Common/Enqueue/Enqueue.php
@@ -4,7 +4,7 @@
 
 use CleantalkSP\Templates\Singleton;
 
-class Enqueue
+abstract class Enqueue
 {
     use Singleton;
 
@@ -83,12 +83,11 @@ private function load($data)
                 throw new \Exception(__('Unknown type of asset.', 'security-malware-firewall'));
             }
         } catch (\Exception $e) {
-            $this->errorLog($e->getMessage());
+            $this->errorAdd($e->getMessage());
         }
-        // output errors to error_log
+        // output errors to static::errorWrite
         if ($this->hasErrors()) {
-            error_log(__CLASS__ . __(' errors:', 'security-malware-firewall'));
-            error_log(implode("\n", $this->errors));
+            static::errorWrite(__CLASS__ . ' errors:' . "\n" . implode("\n", $this->errors));
         }
     }
 
@@ -155,7 +154,7 @@ public function custom($handle, $asset_file_name, $deps, $version, $args, $media
                 )
             );
         } catch (\Exception $e) {
-            $this->errorLog($e->getMessage());
+            $this->errorAdd($e->getMessage());
             $data = null;
         }
         $this->load($data);
@@ -194,7 +193,7 @@ private function prepareData($asset_file_name, $deps, $args, $media)
                 )
             );
         } catch (\Exception $e) {
-            $this->errorLog($e->getMessage());
+            $this->errorAdd($e->getMessage());
         }
         return null;
     }
@@ -270,13 +269,13 @@ private function getFreshVersion($work_script_name)
      */
     private function validateWebPath($path)
     {
-        if (! preg_match('/^https?:\/\//', $path)) {
-            $this->errorLog(__('Web path for script is invalid: ' . $path, 'security-malware-firewall'));
+        if (!preg_match('/^https?:\/\//', $path)) {
+            $this->errorAdd(__('Web path for script is invalid: ' . $path, 'security-malware-firewall'));
             return $path;
         }
         $abs_path = str_replace($this->assets_path, $this->plugin_path, $path);
         if (!@file_exists($abs_path)) {
-            $this->errorLog(__('Script file is not accessible:' . $path, 'security-malware-firewall'));
+            $this->errorAdd(__('Script file is not accessible:' . $path, 'security-malware-firewall'));
             return $path;
         }
         return $path;
@@ -287,7 +286,7 @@ private function validateWebPath($path)
      * @param $message
      * @return void
      */
-    private function errorLog($message)
+    private function errorAdd($message)
     {
         $this->errors[] = $message;
     }
@@ -300,7 +299,7 @@ public function isAllHandlesQueued()
     {
         foreach ($this->handles_to_register as $handle) {
             if (!wp_script_is($handle, 'queue') && !wp_style_is($handle, 'queue')) {
-                $this->errorLog(__('Script is not queued: ' . $handle, 'security-malware-firewall'));
+                $this->errorAdd(__('Script is not queued: ' . $handle, 'security-malware-firewall'));
                 return false;
             }
         }
@@ -315,4 +314,11 @@ public function hasErrors()
     {
         return !empty($this->errors);
     }
+
+    /**
+     * @param string $error
+     *
+     * @return void
+     */
+    abstract public static function errorWrite($error);
 }
diff --git a/lib/CleantalkSP/Common/Helpers/DevLogger.php b/lib/CleantalkSP/Common/Helpers/DevLogger.php
new file mode 100644
index 000000000..dad50f941
--- /dev/null
+++ b/lib/CleantalkSP/Common/Helpers/DevLogger.php
@@ -0,0 +1,31 @@
+<?php
+
+namespace CleantalkSP\Common\Helpers;
+
+/**
+ * Class DevLogger
+ * Base logger class intended to be extended.
+ * Child classes should override the write() method to implement custom logging behavior.
+ *
+ * @package       CleantalkSP\Common\Helpers
+ * @author        Cleantalk team (welcome@cleantalk.org)
+ * @copyright (C) CleanTalk team (http://cleantalk.org)
+ * @license       GNU/GPL: http://www.gnu.org/copyleft/gpl.html
+ * @see           https://github.com/CleanTalk/security-malware-firewall
+ */
+class DevLogger
+{
+    public static function write($msg, $context = null)
+    {
+        if ( ! is_string($msg) ) {
+            return;
+        }
+        if ( ! function_exists('error_log') ) {
+            return;
+        }
+        /**
+         * @psalm-suppress ForbiddenCode
+         */
+        error_log($msg);
+    }
+}
diff --git a/lib/CleantalkSP/Common/Helpers/IP.php b/lib/CleantalkSP/Common/Helpers/IP.php
index 5fa7cc67e..f7a4913de 100644
--- a/lib/CleantalkSP/Common/Helpers/IP.php
+++ b/lib/CleantalkSP/Common/Helpers/IP.php
@@ -679,7 +679,7 @@ public static function isIpv6AddrInIpv6Network($ip, $network, $mask)
                 return false;
             }
         } else {
-            error_log('Security by CleanTalk: PHP insctance is compiled with no inet_pton() IPv6 support.');
+            DevLogger::write('Security by CleanTalk: PHP instance is compiled with no inet_pton() IPv6 support.');
         }
         return false;
     }
diff --git a/lib/CleantalkSP/SpbctWP/AdjustToEnvironmentModule/AdjustToEnv/AdjustToEnvW3TotalCache.php b/lib/CleantalkSP/SpbctWP/AdjustToEnvironmentModule/AdjustToEnv/AdjustToEnvW3TotalCache.php
index cbce77b86..609b5f297 100644
--- a/lib/CleantalkSP/SpbctWP/AdjustToEnvironmentModule/AdjustToEnv/AdjustToEnvW3TotalCache.php
+++ b/lib/CleantalkSP/SpbctWP/AdjustToEnvironmentModule/AdjustToEnv/AdjustToEnvW3TotalCache.php
@@ -2,6 +2,8 @@
 
 namespace CleantalkSP\SpbctWP\AdjustToEnvironmentModule\AdjustToEnv;
 
+use CleantalkSP\SpbctWP\SpbcDevLogger;
+
 class AdjustToEnvW3TotalCache extends AdjustToEnvAbstract
 {
     public function __construct($info)
@@ -99,7 +101,10 @@ class_exists('\W3TC\Dispatcher')
                 $original_config = \W3TC\Dispatcher::config();
                 $state = (bool)$original_config->get('pgcache.cache.query');
             } catch (\Exception $e) {
-                error_log('Security by CleanTalk error: ' . __METHOD__ . ' ' . $e->getMessage());
+                SpbcDevLogger::write(
+                    'W3TC env probing failed: ' . $e->getMessage(),
+                    ['class' => __CLASS__, 'method' => __FUNCTION__]
+                );
             }
         }
         return $state;
@@ -133,7 +138,10 @@ class_exists('\W3TC\Cdnfsd_CacheFlush')
                 $this->changed = !$state;
                 $this->keepEnvChangesByModule();
             } catch (\Exception $e) {
-                error_log('Security by CleanTalk error: ' . __METHOD__ . ' ' . $e->getMessage());
+                SpbcDevLogger::write(
+                    'W3TC config update failed: ' . $e->getMessage(),
+                    ['class' => __CLASS__, 'method' => __FUNCTION__]
+                );
             }
         }
     }
diff --git a/lib/CleantalkSP/SpbctWP/Deactivator.php b/lib/CleantalkSP/SpbctWP/Deactivator.php
index 57e00b01b..fff746b4b 100644
--- a/lib/CleantalkSP/SpbctWP/Deactivator.php
+++ b/lib/CleantalkSP/SpbctWP/Deactivator.php
@@ -4,6 +4,7 @@
 
 use CleantalkSP\SpbctWP\Variables\Cookie;
 use CleantalkSP\SpbctWP\UploadDirPreventPhpExecutionModule\UploadDirPreventPhpExecution;
+use CleantalkSP\SpbctWP\SpbcDevLogger;
 
 class Deactivator
 {
@@ -230,7 +231,7 @@ public static function deactivation($is_network, $do_log_on_errors = false, $is_
         }
 
         if ( $do_log_on_errors && !self::$deactivation_result ) {
-            error_log("Security by CleanTalk deactivation log: \r\n" . var_export(self::getLog(), true));
+            SpbcDevLogger::write("Security by CleanTalk deactivation log: \r\n" . var_export(self::getLog(), true));
         }
 
         // Removing the role of an external technical specialist
diff --git a/lib/CleantalkSP/SpbctWP/FSWatcher/Logger.php b/lib/CleantalkSP/SpbctWP/FSWatcher/Logger.php
index cc8500096..623e9a806 100644
--- a/lib/CleantalkSP/SpbctWP/FSWatcher/Logger.php
+++ b/lib/CleantalkSP/SpbctWP/FSWatcher/Logger.php
@@ -2,6 +2,8 @@
 
 namespace CleantalkSP\SpbctWP\FSWatcher;
 
+use CleantalkSP\SpbctWP\SpbcDevLogger;
+
 class Logger
 {
     private static $logger_dir = __DIR__ . DIRECTORY_SEPARATOR . 'logs';
@@ -43,7 +45,7 @@ public static function log($msg)
         $current_day_log_path = self::getCurrentDayLogPath();
 
         if ( !$current_day_log_path ) {
-            error_log('Cant write log.');
+            SpbcDevLogger::write('Can\'t write log.');
             return;
         }
 
@@ -64,7 +66,11 @@ public static function log($msg)
             }
         }
 
-        error_log($message, 3, $current_day_log_path);
+        $result = @file_put_contents($current_day_log_path, $message . PHP_EOL, FILE_APPEND | LOCK_EX);
+
+        if ($result === false) {
+            SpbcDevLogger::write('Failed to write to log file: ' . $current_day_log_path);
+        }
     }
 
     protected static function generateLogHash()
diff --git a/lib/CleantalkSP/SpbctWP/Firewall/FW.php b/lib/CleantalkSP/SpbctWP/Firewall/FW.php
index 77fbff157..c4f96eed4 100644
--- a/lib/CleantalkSP/SpbctWP/Firewall/FW.php
+++ b/lib/CleantalkSP/SpbctWP/Firewall/FW.php
@@ -4,6 +4,7 @@
 
 use CleantalkSP\SpbctWP\API;
 use CleantalkSP\SpbctWP\DB;
+use CleantalkSP\SpbctWP\SpbcDevLogger;
 use CleantalkSP\Variables\Get;
 use CleantalkSP\Variables\Server;
 use CleantalkSP\Security\Firewall\Result;
@@ -73,7 +74,7 @@ public function check()
                     throw new \Exception('IP address record is invalid.');
                 }
             } catch (\Exception $e) {
-                error_log('Security by CleanTalk. Firewall IP handling error: ' . $e->getMessage());
+                SpbcDevLogger::write('Security by CleanTalk. Firewall IP handling error: ' . $e->getMessage());
                 continue;
             }
 
diff --git a/lib/CleantalkSP/SpbctWP/Scanner/FrontendScan.php b/lib/CleantalkSP/SpbctWP/Scanner/FrontendScan.php
index f3e79fd60..d2a8d72e4 100644
--- a/lib/CleantalkSP/SpbctWP/Scanner/FrontendScan.php
+++ b/lib/CleantalkSP/SpbctWP/Scanner/FrontendScan.php
@@ -371,7 +371,7 @@ public function setContent($content = '')
         try {
             @$this->dom->loadHTML($this->content);
         } catch (\Error $e) { // phpcs:ignore PHPCompatibility.Classes.NewClasses.errorFound
-            error_log($e->getMessage());
+            // Malformed HTML is expected during frontend scans — no point logging it.
         }
 
         return $this;
diff --git a/lib/CleantalkSP/SpbctWP/Scanner/ScannerQueue.php b/lib/CleantalkSP/SpbctWP/Scanner/ScannerQueue.php
index 3024100b7..8cbcd6a33 100644
--- a/lib/CleantalkSP/SpbctWP/Scanner/ScannerQueue.php
+++ b/lib/CleantalkSP/SpbctWP/Scanner/ScannerQueue.php
@@ -36,6 +36,7 @@
 use CleantalkSP\SpbctWP\Scanner\Stages\SendResultsStage;
 use CleantalkSP\SpbctWP\Scanner\Stages\SignatureAnalysis\SignatureAnalysisFacade;
 use CleantalkSP\SpbctWP\Scanner\UnsafePermissionsModule\UnsafePermissionsHandler;
+use CleantalkSP\SpbctWP\SpbcDevLogger;
 use CleantalkSP\SpbctWP\State;
 use CleantalkSP\SpbctWP\Transaction;
 use CleantalkSP\Variables\Request;
@@ -604,7 +605,7 @@ public function get_modules_hashes($amount = null, $offset = null) // phpcs:igno
                             array('slug' => $module_slug, 'fields' => array('Version' => true))
                         );
                     } catch (\Exception $e) {
-                        error_log('Security Scanner - plugins_api exception for ' . $module_slug . ': ' . $e->getMessage());
+                        SpbcDevLogger::write('Security Scanner - plugins_api exception for ' . $module_slug . ': ' . $e->getMessage());
                         $result_wp_api_modules = null;
                     }
                     if ($prev_error_handler !== null) {
@@ -613,7 +614,7 @@ public function get_modules_hashes($amount = null, $offset = null) // phpcs:igno
                         restore_error_handler();
                     }
                     if ($php_errormsg) {
-                        error_log('Security Scanner - plugins_api error for ' . $module_slug . ': ' . $php_errormsg);
+                        SpbcDevLogger::write('Security Scanner - plugins_api error for ' . $module_slug . ': ' . $php_errormsg);
                         $result_wp_api_modules = null;
                     }
                     if ($stored_plugins_api_filters !== null) {
@@ -645,7 +646,7 @@ public function get_modules_hashes($amount = null, $offset = null) // phpcs:igno
                             $wp_filter['themes_api'] = $stored_filters;
                         }
                     } catch (\Exception $e) {
-                        error_log('Security Scanner - Theme API error for ' . $module_slug . ': ' . $e->getMessage());
+                        SpbcDevLogger::write('Security Scanner - Theme API error for ' . $module_slug . ': ' . $e->getMessage());
                         $result_wp_api_modules = new \WP_Error('themes_api_failed', 'Theme API call failed');
                     }
                 }
@@ -881,11 +882,9 @@ public function countFilesByStatusAndChecked($status = '', $caller = '')
     {
         $status = stripslashes(Request::getString('status')) ?: $status;
         if ( Request::getString('checked') ) {
-            error_log(
-                'countFilesByStatusAndChecked: $_GET[\'checked\'] parameter found, but not handled in the method ' . var_export(
-                    $_GET,
-                    true
-                )
+            SpbcDevLogger::write(
+                'countFilesByStatusAndChecked: $_GET[\'checked\'] parameter found, but not handled in the method',
+                ['get' => $_GET]
             );
         }
 
@@ -1462,7 +1461,7 @@ public function signature_analysis($status = 'UNKNOWN,MODIFIED,OK,INFECTED,ERROR
             $spbc->data['scanner']['scanned_total'] = 0;
             $total = $this->countFilesByStatusAndChecked($status_raw, 'SIGNATURE_ANALYSIS');
             if ( ! isset($total['total']) ) {
-                error_log('countFilesByStatusAndChecked: ' . $total['error'] . ' ' . $total['comment']);
+                SpbcDevLogger::write('countFilesByStatusAndChecked: ' . $total['error'] . ' ' . $total['comment']);
             }
             $total = $total['total'];
             $stage_data_obj->set('total_count_files_for_analysis', $total);
@@ -1663,7 +1662,7 @@ public function heuristic_analysis($status = 'UNKNOWN,MODIFIED,OK,INFECTED,ERROR
         if ( $offset === 0 ) {
             $total = $this->countFilesByStatusAndChecked($status_raw, 'HEURISTIC_ANALYSIS');
             if ( ! isset($total['total']) ) {
-                error_log('countFilesByStatusAndChecked() ERROR: ' . $total['error'] . ' ' . $total['comment']);
+                SpbcDevLogger::write('countFilesByStatusAndChecked() ERROR: ' . $total['error'] . ' ' . $total['comment']);
             }
             $total = $total['total'];
             $stage_data_obj->set('total_count_files_for_analysis', $total);
diff --git a/lib/CleantalkSP/SpbctWP/Scanner/Surface.php b/lib/CleantalkSP/SpbctWP/Scanner/Surface.php
index 08e78715f..a8309aa27 100644
--- a/lib/CleantalkSP/SpbctWP/Scanner/Surface.php
+++ b/lib/CleantalkSP/SpbctWP/Scanner/Surface.php
@@ -2,6 +2,8 @@
 
 namespace CleantalkSP\SpbctWP\Scanner;
 
+use CleantalkSP\SpbctWP\SpbcDevLogger;
+
 class Surface
 {
     /**
@@ -698,7 +700,7 @@ public function getFileStructure($main_path, $iterator_result, $is_root_dir)
                     }
                     $this->dirs[]['path'] = $path;
                 } elseif ( is_link($path) ) {
-                    error_log('LINK FOUND: ' . $path);
+                    SpbcDevLogger::write('LINK FOUND: ' . $path);
                 }
             }
             // foreach is finished - iterator completed with no interrupts, save the dir to the completed set
diff --git a/lib/CleantalkSP/SpbctWP/SpbcDevLogger.php b/lib/CleantalkSP/SpbctWP/SpbcDevLogger.php
new file mode 100644
index 000000000..adedaacb4
--- /dev/null
+++ b/lib/CleantalkSP/SpbctWP/SpbcDevLogger.php
@@ -0,0 +1,151 @@
+<?php
+
+namespace CleantalkSP\SpbctWP;
+
+use CleantalkSP\Common\Helpers\DevLogger;
+use CleantalkSP\Common\LoggerRecord;
+
+/**
+ * Developer logger for SPBC WordPress plugin.
+ * Replaces direct error_log() calls so the plugin keeps working when
+ * error_log is disabled via disable_functions or otherwise unavailable.
+ *
+ * Records are persisted in the plugin's State under the `dev_log` option
+ * as a ring buffer of size static::$log_limit: when exceeded, the oldest
+ * entries are evicted and the newest are always saved.
+ */
+class SpbcDevLogger extends DevLogger
+{
+    /**
+     * @var int Maximum number of log entries kept in the ring buffer
+     */
+    protected static $log_limit = 300;
+
+    /**
+     * Write a single line to the dev log.
+     *
+     * @param mixed $msg Main message (JSON encoded if not a string)
+     * @param mixed $context Optional extra payload appended as JSON
+     * @return void
+     */
+    public static function write($msg, $context = null)
+    {
+        $spbc = self::getState();
+        if (!$spbc) {
+            return;
+        }
+
+        $msg = is_string($msg) ? $msg : @json_encode($msg);
+        if ($msg === false) {
+            $msg = 'JSON_ENCODE_ERROR';
+        }
+
+        if ($context !== null) {
+            $ctx = @json_encode($context);
+            if ($ctx === false) {
+                $ctx = 'JSON_ENCODE_ERROR';
+            }
+            if (!empty($ctx)) {
+                $msg .= ', additional data: ' . $ctx;
+            }
+        }
+
+        $record = new LoggerRecord();
+        $record->time = date('Y-m-d H:i:s');
+        $record->message = $msg;
+
+        self::updateStorage($record);
+    }
+
+    /**
+     * Persist a log record to the State storage with ring-buffer trimming.
+     *
+     * @param LoggerRecord $record
+     * @return void
+     */
+    public static function updateStorage($record)
+    {
+        $spbc = self::getState();
+
+        if (!$spbc || !($record instanceof LoggerRecord)) {
+            return;
+        }
+
+        $log = self::loadStorage();
+        $log[] = $record;
+
+        if (count($log) > static::$log_limit) {
+            $log = array_slice($log, -static::$log_limit);
+        }
+
+        $spbc->dev_log = $log;
+        $spbc->save('dev_log', true, false);
+    }
+
+    /**
+     * @return LoggerRecord[]
+     */
+    public static function loadStorage()
+    {
+        $spbc = self::getState();
+
+        if (!$spbc) {
+            return array();
+        }
+
+        $stored = $spbc->dev_log;
+        if ($stored instanceof \ArrayObject) {
+            $stored = $stored->getArrayCopy();
+        }
+
+        return is_array($stored) ? $stored : array();
+    }
+
+    /**
+     * @return void
+     * @psalm-suppress PossiblyUnusedMethod
+     */
+    public static function clearStorage()
+    {
+        $spbc = self::getState();
+        if (!$spbc) {
+            return;
+        }
+
+        $spbc->dev_log = array();
+        $spbc->save('dev_log', true, false);
+    }
+
+    /**
+     * Retrieve all logs as "time : message" formatted strings.
+     *
+     * @return array
+     * @psalm-suppress PossiblyUnusedMethod
+     */
+    public static function getLogAsStringsArray()
+    {
+        $out = array();
+        foreach (self::loadStorage() as $record) {
+            if ($record instanceof LoggerRecord) {
+                $out[] = $record->time . ' : ' . $record->message;
+            }
+        }
+        return $out;
+    }
+
+    /**
+     * @return State|null
+     */
+    public static function getState()
+    {
+        global $spbc;
+        if (
+            !isset($spbc) ||
+            !is_object($spbc) ||
+            !method_exists($spbc, 'save')
+        ) {
+            return null;
+        }
+        return $spbc;
+    }
+}
diff --git a/lib/CleantalkSP/SpbctWP/SpbcEnqueue.php b/lib/CleantalkSP/SpbctWP/SpbcEnqueue.php
index 08cbf1895..055f7b1c2 100644
--- a/lib/CleantalkSP/SpbctWP/SpbcEnqueue.php
+++ b/lib/CleantalkSP/SpbctWP/SpbcEnqueue.php
@@ -419,4 +419,14 @@ private static function jqAddBuiltIn()
         wp_enqueue_script('jquery-ui-resizable');
         wp_enqueue_script('jquery-ui-dialog');
     }
+
+    /**
+     * @param string $error
+     *
+     * @return void
+     */
+    public static function errorWrite($error)
+    {
+        SpbcDevLogger::write($error);
+    }
 }
diff --git a/lib/CleantalkSP/SpbctWP/SpbcRateLimit/SpbcRateLimiter.php b/lib/CleantalkSP/SpbctWP/SpbcRateLimit/SpbcRateLimiter.php
index 816430758..7d71f5347 100644
--- a/lib/CleantalkSP/SpbctWP/SpbcRateLimit/SpbcRateLimiter.php
+++ b/lib/CleantalkSP/SpbctWP/SpbcRateLimit/SpbcRateLimiter.php
@@ -7,6 +7,7 @@
 use CleantalkSP\Common\TextPlate;
 use CleantalkSP\Common\TT;
 use CleantalkSP\SpbctWP\Helpers\IP;
+use CleantalkSP\SpbctWP\SpbcDevLogger;
 use CleantalkSP\Variables\Server;
 
 /**
@@ -84,7 +85,7 @@ protected function handleErrors(string $msg): void
                     'period' => esc_html(TT::toString($this->config->period)),
                 )
             );
-            error_log($error);
+            SpbcDevLogger::write($error);
         }
     }
 
diff --git a/lib/CleantalkSP/SpbctWP/State.php b/lib/CleantalkSP/SpbctWP/State.php
index 9c1288458..af5e8d37d 100644
--- a/lib/CleantalkSP/SpbctWP/State.php
+++ b/lib/CleantalkSP/SpbctWP/State.php
@@ -25,6 +25,7 @@
  * @property mixed network_data
  * @property mixed errors
  * @property mixed fw_stats
+ * @property mixed dev_log
  * @property SpbcFWUpdateLogger update_logger
  * @psalm-suppress PossiblyUnusedProperty
  */
@@ -493,7 +494,8 @@ public static function resetState()
                 'debug',
                 'installing',
                 'errors',
-                'fw_stats'
+                'fw_stats',
+                'dev_log'
             ),
             is_multisite(),
             is_main_site()
diff --git a/psalm.xml b/psalm.xml
index d50620109..dd411c963 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -31,6 +31,7 @@
 
     <forbiddenFunctions>
         <function name="check_ajax_referer" />
+        <function name="error_log" />
     </forbiddenFunctions>
 
     <issueHandlers>
diff --git a/security-malware-firewall.php b/security-malware-firewall.php
index e5a25ebba..da403c5a7 100644
--- a/security-malware-firewall.php
+++ b/security-malware-firewall.php
@@ -25,6 +25,7 @@
 use CleantalkSP\SpbctWP\RemoteCalls as SpbcRemoteCalls;
 use CleantalkSP\SpbctWP\RenameLoginPage;
 use CleantalkSP\SpbctWP\Sanitize;
+use CleantalkSP\SpbctWP\SpbcDevLogger;
 use CleantalkSP\SpbctWP\Scanner\Services\SendFileToCloudService;
 use CleantalkSP\SpbctWP\Scanner\Stages\SignatureAnalysis\SignatureAnalysisFacade;
 use CleantalkSP\SpbctWP\Settings\FilesScanPathExclusion;
@@ -1628,7 +1629,7 @@ function spbc_send_daily_report($skip_data_rotation = false)
 
         $admin_email = spbc_get_admin_email();
         if ( ! $admin_email ) {
-            error_log(
+            SpbcDevLogger::write(
                 sprintf(
                     '%s: can\'t send the Daily report because of empty Admin email. File: %s, line %d.',
                     $spbc->data["wl_brandname"],
diff --git a/tests/lib/CleantalkSP/SpbctWP/TestSpbcDevLogger.php b/tests/lib/CleantalkSP/SpbctWP/TestSpbcDevLogger.php
new file mode 100644
index 000000000..4eaa0bba6
--- /dev/null
+++ b/tests/lib/CleantalkSP/SpbctWP/TestSpbcDevLogger.php
@@ -0,0 +1,224 @@
+<?php
+
+use CleantalkSP\Common\LoggerRecord;
+use CleantalkSP\SpbctWP\SpbcDevLogger;
+
+class TestSpbcDevLogger extends SpbcTestCase
+{
+    /**
+     * Reset dev_log before each test so tests are independent.
+     */
+    protected function setUp(): void
+    {
+        parent::setUp();
+        global $spbc;
+        $spbc->dev_log = array();
+    }
+
+    public function testGetStateReturnsSpbc()
+    {
+        global $spbc;
+        $this->assertInstanceOf(\CleantalkSP\SpbctWP\State::class, SpbcDevLogger::getState());
+        $this->assertSame($spbc, SpbcDevLogger::getState());
+    }
+
+    public function testGetStateReturnsNullWhenSpbcInvalid()
+    {
+        global $spbc;
+        $backup = $spbc;
+        $spbc = null;
+
+        $this->assertNull(SpbcDevLogger::getState());
+
+        $spbc = $backup;
+    }
+
+    public function testWriteAddsSingleRecord()
+    {
+        SpbcDevLogger::write('hello dev log');
+
+        $storage = SpbcDevLogger::loadStorage();
+
+        $this->assertCount(1, $storage);
+        $this->assertInstanceOf(LoggerRecord::class, $storage[0]);
+        $this->assertStringContainsString('hello dev log', $storage[0]->message);
+        $this->assertNotEmpty($storage[0]->time);
+    }
+
+    public function testWriteAppendsContextAsAdditionalData()
+    {
+        SpbcDevLogger::write('msg', array('key' => 'value', 'num' => 42));
+
+        $storage = SpbcDevLogger::loadStorage();
+
+        $this->assertCount(1, $storage);
+        $this->assertStringContainsString('msg', $storage[0]->message);
+        $this->assertStringContainsString('additional data: {"key":"value","num":42}', $storage[0]->message);
+    }
+
+    public function testWriteMultipleRecordsKeepsOrder()
+    {
+        SpbcDevLogger::write('one');
+        SpbcDevLogger::write('two');
+        SpbcDevLogger::write('three');
+
+        $storage = SpbcDevLogger::loadStorage();
+
+        $this->assertCount(3, $storage);
+        $this->assertStringContainsString('one', $storage[0]->message);
+        $this->assertStringContainsString('two', $storage[1]->message);
+        $this->assertStringContainsString('three', $storage[2]->message);
+    }
+
+    public function testUpdateStorageDirectlyAddsRecord()
+    {
+        global $spbc;
+
+        $record = new LoggerRecord();
+        $record->time = '2026-05-14 12:00:00';
+        $record->message = 'direct record';
+
+        SpbcDevLogger::updateStorage($record);
+
+        $this->assertCount(1, $spbc->dev_log);
+        $this->assertSame('direct record', $spbc->dev_log[0]->message);
+        $this->assertSame('2026-05-14 12:00:00', $spbc->dev_log[0]->time);
+    }
+
+    public function testUpdateStorageIgnoresNonLoggerRecord()
+    {
+        global $spbc;
+
+        SpbcDevLogger::updateStorage('not a LoggerRecord');
+        SpbcDevLogger::updateStorage(array('also' => 'not'));
+        SpbcDevLogger::updateStorage(null);
+
+        $this->assertSame(array(), $spbc->dev_log);
+    }
+
+    public function testUpdateStorageNoStateDoesNotThrow()
+    {
+        global $spbc;
+        $backup = $spbc;
+        $spbc = null;
+
+        $record = new LoggerRecord();
+        $record->time = '2026-05-14 12:00:00';
+        $record->message = 'lost';
+
+        SpbcDevLogger::updateStorage($record);
+
+        $this->assertTrue(true);
+
+        $spbc = $backup;
+    }
+
+    public function testLoadStorageReturnsEmptyArrayWhenStateMissing()
+    {
+        global $spbc;
+        $backup = $spbc;
+        $spbc = null;
+
+        $result = SpbcDevLogger::loadStorage();
+
+        $this->assertSame(array(), $result);
+
+        $spbc = $backup;
+    }
+
+    public function testLoadStorageReturnsEmptyArrayWhenDevLogIsNotArray()
+    {
+        global $spbc;
+        $spbc->dev_log = 'unexpected scalar';
+
+        $this->assertSame(array(), SpbcDevLogger::loadStorage());
+    }
+
+    public function testLoadStorageHandlesArrayObject()
+    {
+        global $spbc;
+
+        $record = new LoggerRecord();
+        $record->message = 'inside ArrayObject';
+
+        $spbc->dev_log = new \ArrayObject(array($record));
+
+        $result = SpbcDevLogger::loadStorage();
+
+        $this->assertTrue(is_array($result));
+        $this->assertCount(1, $result);
+        $this->assertSame('inside ArrayObject', $result[0]->message);
+    }
+
+    public function testClearStorageEmptiesLog()
+    {
+        SpbcDevLogger::write('to be cleared');
+        $this->assertCount(1, SpbcDevLogger::loadStorage());
+
+        SpbcDevLogger::clearStorage();
+
+        $this->assertSame(array(), SpbcDevLogger::loadStorage());
+    }
+
+    public function testClearStorageNoStateDoesNotThrow()
+    {
+        global $spbc;
+        $backup = $spbc;
+        $spbc = null;
+
+        SpbcDevLogger::clearStorage();
+
+        $this->assertTrue(true);
+
+        $spbc = $backup;
+    }
+
+    /**
+     * Ring-buffer behavior: once $log_limit is exceeded, the oldest record
+     * is evicted and the newest is always saved. Reflection is used to read
+     * the protected $log_limit so the test doesn't break if it's later tuned.
+     */
+    public function testRingBufferEvictsOldestWhenExceeded()
+    {
+        $ref = new \ReflectionClass(SpbcDevLogger::class);
+        $prop = $ref->getProperty('log_limit');
+        $prop->setAccessible(true);
+        $ring_size = (int)$prop->getValue();
+
+        $overflow = $ring_size + 5;
+
+        for ($i = 0; $i < $overflow; $i++) {
+            SpbcDevLogger::write('msg ' . $i);
+        }
+
+        $storage = SpbcDevLogger::loadStorage();
+
+        $this->assertCount(
+            $ring_size,
+            $storage,
+            'Ring buffer must cap storage at exactly $log_limit records.'
+        );
+        $this->assertStringContainsString(
+            'msg ' . ($overflow - $ring_size),
+            $storage[0]->message,
+            'Oldest record after eviction must be the first non-evicted one.'
+        );
+        $this->assertStringContainsString(
+            'msg ' . ($overflow - 1),
+            $storage[$ring_size - 1]->message,
+            'Newest record must be the last one written.'
+        );
+    }
+
+    public function testGetLogAsStringsArrayFormatsRecords()
+    {
+        SpbcDevLogger::write('formatted message');
+
+        $lines = SpbcDevLogger::getLogAsStringsArray();
+
+        $this->assertTrue(is_array($lines));
+        $this->assertNotEmpty($lines);
+        $this->assertStringContainsString(' : ', $lines[0]);
+        $this->assertStringContainsString('formatted message', $lines[0]);
+    }
+}