diff --git a/inc/error.php b/inc/error.php
index 7ebf6296..fed211ac 100644
--- a/inc/error.php
+++ b/inc/error.php
@@ -2,12 +2,20 @@
 namespace Vichan;
 
 class ErrorHandler {
+	private static array|false $error_recursion = false;
+
 	private bool $include_details;
 	/**
 	 * @var callable
 	 */
 	private mixed $logger_fn;
 
+
+	private static function isCli(): bool {
+		return defined('STDIN') || \PHP_SAPI === 'cli' || (\stristr(\PHP_SAPI, 'cgi') && \getenv('TERM'))
+			|| (empty($_SERVER['REMOTE_ADDR']) && !isset($_SERVER['HTTP_USER_AGENT']) && \count($_SERVER['argv']) > 0);
+	}
+
 	private static function errnoToLogLevel(int $errno): int {
 		switch ($errno) {
 			default:
@@ -16,9 +24,9 @@ class ErrorHandler {
 			case \E_CORE_ERROR:
 			case \E_COMPILE_ERROR:
 			case \E_RECOVERABLE_ERROR:
-				return  \LOG_EMERG;
+				return \LOG_EMERG;
 			case \E_USER_ERROR:
-				return  \LOG_ERR;
+				return \LOG_ERR;
 			case \E_WARNING:
 			case \E_CORE_WARNING:
 			case \E_COMPILE_WARNING:
@@ -37,11 +45,84 @@ class ErrorHandler {
 		string $message,
 		callable $logger,
 		bool $display_details,
-		?string $file,
-		?int $line,
-		?string $trace,
+		string $file,
+		int $line,
+		string $trace_str,
+		array $trace
 	): void {
+		global $board, $mod, $config, $db_error;
 
+		$newline = self::isCli() ? '\n' : '<br>';
+
+		if (self::$error_recursion !== false) {
+			list($o_message, $o_file, $o_line, $o_trace) = self::$error_recursion;
+			if ($display_details) {
+				echo("Error recursion detected with $message at $file:$line. Backtrace:$newline$trace_str{$newline}Original error: $o_message at $o_file:$o_line. Original backtrace:$newline$o_trace");
+			} else {
+				echo("Error recursion detected with $message{$newline}Original error: $o_message");
+			}
+			exit;
+		}
+
+		self::$error_recursion = [ $message, $file, $line, $trace_str ];
+
+		// Message for the system, be it cli or error logging facility.
+		$sys_msg = "Error: $message at $file:$line.\nBacktrace: $trace_str\n";
+
+		if (self::isCli()) {
+			// Running from CLI. Always display the details.
+			echo($sys_msg);
+			exit;
+		}
+
+		// Log the error if we aren't running from cli.
+		$logger($level, $sys_msg);
+
+		// Recycled code.
+		$debug_stuff = [];
+		if ($config['debug']) {
+			if (isset($db_error)) {
+				$debug_stuff = \array_combine([ 'SQLSTATE', 'Error code', 'Error message' ], $db_error);
+			}
+			$debug_stuff['backtrace'] = $trace;
+
+			// Remove the password from SQL errors.
+			$pw = $config['db']['password'];
+			$debug_callback = function($item) use (&$debug_callback, $pw) {
+				if (\is_array($item)) {
+					$item = \array_filter($item, $debug_callback);
+				}
+				return $item !== $pw || !$pw;
+			};
+			$debug_stuff = \array_map($debug_callback, $debug_stuff);
+		}
+
+		\header("{$_SERVER['SERVER_PROTOCOL']} 500 Internal Server Error");
+
+		// Error via json.
+		if (isset($_POST['json_response'])) {
+			\header('Content-Type: text/json; charset=utf-8');
+			$data = [ 'error' => $message ];
+			if (!empty($config) && $config['debug'] && !empty($debug_stuff)) {
+				$data['debug'] = $debug_stuff;
+			}
+			echo(\json_encode($data));
+			exit;
+		}
+
+		// Pretty print.
+		die(Element('page.html', [
+			'config' => $config,
+			'title' => _('Error'),
+			'subtitle' => _('An error has occured.'),
+			'body' => Element('error.html', [
+				'config' => $config,
+				'message' => $message,
+				'mod' => $mod,
+				'board' => isset($board) ? $board : false,
+				'debug' => \str_replace("\n", '&#10;', utf8tohtml(print_r($debug_stuff, true)))
+			])
+		]));
 	}
 
 	private function default_logger(int $level, string $message) {
@@ -54,9 +135,13 @@ class ErrorHandler {
 		}
 	}
 
+	public function __construct() {
+		$this->include_details = self::isCli();
+		$this->logger_fn = [ __CLASS__, 'default_logger' ];
+	}
+
 	public function setIncludeDetails(bool $include_details) {
 		$this->include_details = $include_details;
-		$this->logger_fn = [ __CLASS__, 'default_logger' ];
 	}
 
 	public function setLogger(?callable $logger_fn) {
@@ -65,7 +150,7 @@ class ErrorHandler {
 
 	public function installGlobally() {
 		$logger_fn = $this->logger_fn;
-		$include_details = $this->include_details;
+		$include_details = $this->include_details || self::isCli();
 
 		\set_error_handler(function($errno, $errstr, $errfile, $errline) use ($logger_fn, $include_details) {
 			$errno = \error_reporting() & $errno;
@@ -73,8 +158,10 @@ class ErrorHandler {
 				$level = self::errnoToLogLevel($errno);
 
 				// https://stackoverflow.com/a/35930682
-				$trace = (new \Exception)->getTraceAsString();
-				self::handle_error($level, $errstr, $logger_fn, $include_details, $errfile, $errline, $trace);
+				$e = new \Exception();
+				$trace_str = $e->getTraceAsString();
+				$trace = $e->getTrace();
+				self::handle_error($level, $errstr, $logger_fn, $include_details, $errfile, $errline, $trace_str, $trace);
 			}
 			return false;
 		});
@@ -83,9 +170,10 @@ class ErrorHandler {
 			$message = $exception->getMessage();
 			$file = $exception->getFile();
 			$line = $exception->getLine();
-			$trace = $exception->getTraceAsString();
+			$trace_str = $exception->getTraceAsString();
+			$trace = $exception->getTrace();
 
-			self::handle_error(\LOG_EMERG, $message, $logger_fn, $include_details, $file, $line, $trace);
+			self::handle_error(\LOG_EMERG, $message, $logger_fn, $include_details, $file, $line, $trace_str, $trace);
 		});
 
 		\register_shutdown_function(function() use ($logger_fn, $include_details) {
@@ -96,7 +184,7 @@ class ErrorHandler {
 				$file = $error['file'];
 				$line = $error['line'];
 
-				self::handle_error($level, $message, $logger_fn, $include_details, $file, $line, null);
+				self::handle_error($level, $message, $logger_fn, $include_details, $file, $line, '<UNAVAILABLE>', []);
 			}
 		});
 	}
@@ -212,7 +300,7 @@ function error($message, $priority = true, $debug_stuff = false) {
 			'message' => $message,
 			'mod' => $mod,
 			'board' => isset($board) ? $board : false,
-			'debug' => str_replace("\n", '&#10;', utf8tohtml(print_r($debug_stuff, true)))
+			'debug' => \str_replace("\n", '&#10;', utf8tohtml(\print_r($debug_stuff, true)))
 		))
 	]));
 }