diff --git a/blockbot/blockbot.php b/blockbot/blockbot.php
index 30ecc3a6..c16489d8 100644
--- a/blockbot/blockbot.php
+++ b/blockbot/blockbot.php
@@ -8,9 +8,11 @@
  */
 
 use Friendica\App;
+use Friendica\Core\Config;
 use Friendica\Core\Hook;
 use Friendica\Core\System;
 use Jaybizzle\CrawlerDetect\CrawlerDetect;
+use Friendica\Core\Logger;
 
 require_once __DIR__ . DIRECTORY_SEPARATOR . 'vendor' . DIRECTORY_SEPARATOR . 'autoload.php';
 
@@ -24,9 +26,64 @@ function blockbot_uninstall() {
 }
 
 function blockbot_init_1(App $a) {
+	if (empty($_SERVER['HTTP_USER_AGENT'])) {
+		return;
+	}
+
+	$logdata = ['agent' => $_SERVER['HTTP_USER_AGENT'], 'uri' => $_SERVER['REQUEST_URI']];
+
+	// List of known crawlers.
+	$agents = ['SemrushBot', 's~feedly-nikon3', 'Qwantify/Bleriot/', 'ltx71', 'Sogou web spider/',
+		'Diffbot/', 'Twitterbot/', 'YisouSpider', 'evc-batch/', 'LivelapBot/', 'TrendsmapResolver/',
+		'PaperLiBot/', 'Nuzzel', 'um-LN/', 'Google Favicon', 'Datanyze', 'BLEXBot/', '360Spider',
+		'adscanner/', 'HeadlessChrome', 'wpif', 'startmebot/', 'Googlebot/', 'Applebot/',
+		'facebookexternalhit/', 'GoogleImageProxy', 'bingbot/', 'heritrix/', 'ldspider',
+		'AwarioRssBot/', 'Zabbix', 'TweetmemeBot/', 'dcrawl/', 'PhantomJS/', 'Googlebot-Image/',
+		'CrowdTanglebot/', 'Mediapartners-Google', 'Baiduspider/', 'datagnionbot',
+		'MegaIndex.ru/', 'SMUrlExpander', 'Hatena-Favicon/', 'Wappalyzer', 'FlipboardProxy/',
+		'NetcraftSurveyAgent/', 'Dataprovider.com', 'SMTBot/', 'Nimbostratus-Bot/',
+		'DuckDuckGo-Favicons-Bot/', 'IndieWebCards/', 'proximic', 'netEstate NE Crawler',
+		'AhrefsBot/', 'YandexBot/', 'Exabot/', 'Mediumbot-MetaTagFetcher/', 'WhatsApp/',
+		'TelegramBot', 'SurdotlyBot/', 'BingPreview/', 'SabsimBot/', 'CCBot/', 'WbSrch/',
+		'DuckDuckBot-Https/', 'HTTP Banner Detection', 'YandexImages/', 'archive.org_bot',
+		'ArchiveTeam ArchiveBot/', 'yacybot', 'https://developers.google.com/+/web/snippet/',
+		'Scrapy/', 'github-camo', 'MJ12bot/', 'DotBot/', 'Pinterestbot/', 'Jooblebot/',
+		'Cliqzbot/', 'YaK/', 'Mediatoolkitbot'];
+
+	foreach ($agents as $agent) {
+		if (stristr($_SERVER['HTTP_USER_AGENT'], $agent)) {
+			System::httpExit(403, 'Bots are not allowed');
+		}
+	}
+
+	// This switch here is only meant for developers who want to add more bots to the list above, it is not safe for production.
+	if (!Config::get('blockbot', 'training')) {
+		return;
+	}
+
 	$crawlerDetect = new CrawlerDetect();
 
-	if ($crawlerDetect->isCrawler()) {
-		System::httpExit(403, 'Bots are not allowed');
+	if (!$crawlerDetect->isCrawler()) {
+		logger::debug('Good user agent detected', $logdata);
+		return;
 	}
+
+	// List of false positives' strings of known "good" agents.
+	$agents = ['fediverse.network crawler', 'Active_Pods_CheckBot_3.0', 'Social-Relay/',
+		'curl', 'zgrab', 'Go-http-client', 'curb', 'github.com', 'reqwest', 'Feedly/',
+		'Python-urllib/', 'Liferea/', 'aiohttp/', 'WordPress.com Reader', 'hackney/',
+		'Faraday v', 'okhttp', 'UniversalFeedParser', 'PixelFedBot', 'python-requests',
+		'WordPress/', 'http.rb/', 'Apache-HttpClient/', 'WordPress.com;', 'Pleroma',
+		'Dispatch/', 'Ruby', 'Uptimebot/', 'Java/', 'libwww-perl/', 'Mastodon/',
+		'lua-resty-http/', 'Test Certificate Info'];
+
+	foreach ($agents as $agent) {
+		if (stristr($_SERVER['HTTP_USER_AGENT'], $agent)) {
+			logger::notice('False positive', $logdata);
+			return;
+		}
+	}
+
+	logger::info('Blocked bot', $logdata);
+	System::httpExit(403, 'Bots are not allowed');
 }
diff --git a/twitter/twitter.php b/twitter/twitter.php
index b38ee92d..faf814da 100644
--- a/twitter/twitter.php
+++ b/twitter/twitter.php
@@ -575,7 +575,7 @@ function twitter_post_hook(App $a, array &$b)
 		return;
 	}
 
-	Logger::log('twitter post invoked');
+	Logger::notice('twitter post invoked', ['id' => $b['id'], 'guid' => $b['guid']]);
 
 	PConfig::load($b['uid'], 'twitter');
 
@@ -610,6 +610,7 @@ function twitter_post_hook(App $a, array &$b)
 		$b['body'] = twitter_update_mentions($b['body']);
 
 		$msgarr = ItemContent::getPlaintextPost($b, $max_char, true, 8);
+		Logger::info('Got plaintext', $msgarr);
 		$msg = $msgarr["text"];
 
 		if (($msg == "") && isset($msgarr["title"])) {