diff --git a/README.rst b/README.rst
index 88d5b1f..96afe95 100644
--- a/README.rst
+++ b/README.rst
@@ -47,3 +47,18 @@ Using logger
   logger.warn('warn message')
   logger.error('error message')
   logger.critical('critical message')
+
+Using filter
+''''''''''''
+
+You can also filter some messages only
+
+.. code-block:: python
+
+    from slack_logger import SlackLogFilter
+    
+    sf = SlackLogFilter()
+    sh.addFilter(sf)
+    
+    logger.info('info message')  # Not posted to slack
+    logger.info('info message to slack', extra={'notify_slack': True})  # Posted to slack
diff --git a/slack_logger.py b/slack_logger.py
index 0962807..5bba91b 100644
--- a/slack_logger.py
+++ b/slack_logger.py
@@ -58,3 +58,15 @@ def format(self, record):
         ret['ts'] = record.created
         ret['text'] = super(SlackFormatter, self).format(record)
         return ret
+
+
+class SlackLogFilter(logging.Filter):
+    """
+    Logging filter to decide when logging to Slack is requested, using
+    the `extra` kwargs:
+
+        `logger.info("...", extra={'notify_slack': True})`
+    """
+
+    def filter(self, record):
+        return getattr(record, 'notify_slack', False)