Snake under doormat what to do is a real doorstep safety problem because the hiding place is flat, dark, and close to hands, ankles, packages, and pet paws. Most people create the risk themselves by lifting the mat a second time or trying to shake it out near the threshold.
Do not grab the edge again, slide fingers under the mat, or step barefoot into the doorway while the snake's position is uncertain. Move everyone back, use the door from another exit if possible, and note whether the snake is under the center of the mat, against the wall, beside the trim, or moving toward nearby landscaping.
Doormats attract snakes for the same reason loose boards, pavers, and porch clutter do: they create a cool tight refuge next to heat-retaining surfaces and insect activity. A snake may pause there only briefly, but that is enough to create a surprise exactly where people stop looking.
If the animal remains visible, take one photo from outside striking distance and leave the mat where it is. Do not pin the mat down with a broom or flick it over toward yourself. Quick mat movement removes your reaction time and can send the snake along the threshold, under a planter, or back toward the doorway.
SnakeSnap can help compare likely species from a safe photo, but treat low confidence as unresolved. If the app suggests a venomous possibility or the snake disappears into the entry area you need to use, contact local wildlife help. Long term, keep porch edges clear, reduce insect-attracting lights near the threshold, and shake mats only after checking from a distance.