Widget Messages Read

The visitor has had this message on screen (public, no auth). Sent by the widget only while its panel is open in a visible tab — the cursor poll keeps running behind a collapsed panel, so "the server handed it out" is not "the visitor saw it". This is what decides whether an operator's reply is mailed to the visitor after the grace period. The cursor only ever advances; a receipt for an older message is accepted and ignored.

curl -X POST "https://api.getchat9.live/widget/messages/read?bot_id=string&session_id=string" \
  -H "Content-Type: application/json" \
  -d '{
    "message_id": "d7d9d9fd-478f-40e6-b651-49b7f19878a2"
  }'

{
  "session_id": "1ffd059c-17ea-40a8-8aef-70fd0307db82",
  "read_message_id": "18f523f2-10d5-468a-b819-c1132de3596a"
}