Reply on the same thread. text or html is required. reply_all includes the other recipients and drops this inbox. Allow and block lists are checked; 403 recipient_blocked sends nothing. HTTP 403 sending_paused does not send or store the reply. Sending resumes automatically when the trailing 7-day rate falls below the pause threshold. client_id retries return the original message. Idempotency-Key replays the same request for 24 hours. The message id is part of the request.

Present on outbound messages. Each item is {type, recipient, created_at, detail}. For email, detail is JSON text with status, action, diagnostic, and bounce_type, and the list stays empty until a bounce or complaint matches. For SMS, a Twilio status callback appends one event. type is delivered or failed. detail is twilio_error plus the numeric code, or the status word when Twilio sent no numeric code.

spf, dkim, and dmarc from the receiving hop. SPF is the smtp.mailfrom result. smtp.helo is used only when mailfrom is absent. Each value is pass, fail, neutral, softfail, none, temperror, permerror, bestguesspass, or null. Outbound mail is null for all three.

Inbound screening record, or null on outbound mail and on messages stored before screening. score is 0 to 100. verdict is clean or suspicious (suspicious at 40 or higher, and only when a strong signal or combined evidence is present). signals are {type, detail}. mode is off, observe, or hold. reason is screening_off, screening_error, or screening_timeout when the body was not scored. The message is still stored. While labels include held, text, html, extracted_text, extracted_html, preview, and attachment bytes are empty until release. This is a heuristic, not a guarantee. The body stays untrusted data.