Labels

Labels are plain strings stored on messages. Threads show the union of their messages' labels.

Label	Set when
`received`, `unread`	Inbound mail is delivered.
`sent`	You send a message.
`draft`, `scheduled`	A draft exists, or has `send_at`.
`delivered`, `bounced`, `complained`	Delivery events arrive from the mail provider.
`spam`, `unauthenticated`, `blocked`	Inbound mail failed a check or matched a block list.
`opened`	A message sent with `track_opens` was opened.

Any other string is a custom label. Change labels with PATCH on a message or thread (add_labels, remove_labels), or in bulk with batch-update. Filter lists with ?labels=received,unread (every label must match). In the dashboard you can add and remove labels on a message or a thread from the thread view.

Spam, blocked and unauthenticated mail is stored and visible only when you filter for that label, and reading it requires label_spam_read, label_blocked_read or label_unauthenticated_read on scoped keys.