# Receive mail and read threads > Work with incoming messages, labels, complete threads, and real-time notifications. ## How receiving starts Incoming mail reaches Startup Mail after the domain’s MX record is verified and a matching mailbox exists. Unknown recipients are not catch-all routed. Accepted messages appear in the web inbox and become available to API, SDK, webhook, and MCP integrations with the right access. ## List threads Use `GET /v1/threads` or `mail.listThreads()`. Filter with a mailbox ID and one of these labels: `inbox`, `starred`, `sent`, `drafts`, `important`, or `spam`. ```ts const threads = await mail.listThreads({ mailboxId: "mbx_123", label: "inbox", }); ``` A thread summary includes subject, snippet, sender, last-message time, unread and message counts, starred and important state, and whether it has attachments. ## Read a complete thread Use `GET /v1/threads/:id` or `mail.getThread(threadId)`. The response contains messages in the conversation, including direction, delivery status, addresses, plain and cleaned HTML bodies, timestamps, and attachment metadata. Access is checked when the thread is requested. Knowing a thread ID does not bypass private mailbox permissions. ## React without polling Subscribe to `message.received` with a signed webhook. Its payload identifies the mailbox, thread, and message so your worker can fetch the complete thread using `mail:read` scope. > **Fetch after the event** > > Treat a webhook as a durable notification, not a replacement for the API response. Use its IDs to > retrieve the current thread and make your processing idempotent.