diff --git a/httpd.py b/httpd.py
index 576c64b..ece8f91 100644
--- a/httpd.py
+++ b/httpd.py
@@ -350,6 +350,40 @@ def get_worker_test_rate(worker_id):
             return 0.0
         return total_tests / elapsed
 
+def _get_proto_boost():
+    """Calculate protocol scarcity boost for URL scoring.
+
+    Returns a value 0.0-1.0 to boost SOCKS sources when SOCKS proxies
+    are underrepresented relative to HTTP. Returns 0.0 when balanced.
+    """
+    try:
+        db = mysqlite.mysqlite(_proxy_database, str) if _proxy_database else None
+        if not db:
+            return 0.0
+        row = db.execute(
+            "SELECT "
+            "  SUM(CASE WHEN proto='http' THEN 1 ELSE 0 END),"
+            "  SUM(CASE WHEN proto IN ('socks4','socks5') THEN 1 ELSE 0 END)"
+            " FROM proxylist WHERE failed=0"
+        ).fetchone()
+        if not row or not row[0]:
+            return 0.5  # no data, default mild boost
+        http_count, socks_count = row[0] or 0, row[1] or 0
+        total = http_count + socks_count
+        if total == 0:
+            return 0.5
+        socks_ratio = float(socks_count) / total
+        # Boost SOCKS sources when socks_ratio < 40%
+        if socks_ratio >= 0.4:
+            return 0.0
+        return min((0.4 - socks_ratio) * 2.5, 1.0)  # 0.0-1.0 scale
+    except Exception:
+        return 0.0
+
+# Global reference to proxy database path (set by ProxyAPIServer.__init__)
+_proxy_database = None
+
+
 def claim_urls(url_db, worker_id, count=5):
     """Claim a batch of URLs for worker-driven fetching. Returns list of URL dicts.
 
@@ -360,6 +394,7 @@ def claim_urls(url_db, worker_id, count=5):
       - quality_bonus: 0-0.5 based on working_ratio
       - error_penalty: 0-2.0 based on consecutive errors
       - stale_penalty: 0-1.0 based on unchanged fetches
+      - proto_boost: 0-1.0 for SOCKS sources when SOCKS underrepresented
     """
     now = time.time()
     now_int = int(now)
@@ -385,6 +420,9 @@ def claim_urls(url_db, worker_id, count=5):
     list_max_age_seconds = _url_list_max_age_days * 86400
     min_added = now_int - list_max_age_seconds
 
+    # Boost SOCKS sources when protocol pool is imbalanced
+    proto_boost = _get_proto_boost()
+
     try:
         rows = url_db.execute(
             '''SELECT url, content_hash,
@@ -393,6 +431,8 @@ def claim_urls(url_db, worker_id, count=5):
                 + COALESCE(working_ratio, 0) * 0.5
                 - MIN(error * 0.3, 2.0)
                 - MIN(stale_count * 0.1, 1.0)
+                + CASE WHEN LOWER(url) LIKE '%socks5%' OR LOWER(url) LIKE '%socks4%'
+                       THEN ? ELSE 0 END
                 AS score
             FROM uris
             WHERE error < ?
@@ -400,7 +440,7 @@ def claim_urls(url_db, worker_id, count=5):
                 AND (added > ? OR proxies_added > 0)
             ORDER BY score DESC
             LIMIT ?''',
-            (now_int, _url_max_fail, now_int, min_added, count * 3)
+            (now_int, proto_boost, _url_max_fail, now_int, min_added, count * 3)
         ).fetchall()
     except Exception as e:
         _log('claim_urls query error: %s' % e, 'error')
@@ -1355,8 +1395,9 @@ class ProxyAPIServer(threading.Thread):
         self.stats_provider = stats_provider
         self.profiling = profiling
         self.daemon = True
-        global _url_database_path
+        global _url_database_path, _proxy_database
         _url_database_path = url_database
+        _proxy_database = database
         self.server = None
         self._stop_event = threading.Event() if not GEVENT_PATCHED else None
         # Load static library files into cache