Example of headers created by Stalwart below X-Spam-Result: TRUSTED_DOMAIN (-7.00), PROB_HAM_LOW (-2.00), RBL_SENDERSCORE_REPUT_9 (-1.00), DMARC_POLICY_ALLOW (-0.50), RCVD_DKIM_ARC_DNSWL_MED (-0.50) X-Spam-Score: ham, score=-5.60, avg_confidence=0.26 X-Spam-Status: No Only need to add small tweak by detecting spam|ham as well as Yes|No The most useful header is X-Spam-Score, so we make sure to parse that before X-Spam-Status