{
  "product": "Specification (reference)",
  "title": "SMTP Submission",
  "summary": "Handing an email to a server so that it arrives rather than lands in spam.",
  "category": "protocols",
  "entries": [
    {
      "path": [
        "AI",
        "Connection",
        "Submission on port 587 with STARTTLS"
      ],
      "value": "",
      "status": "yes",
      "note": "or implicit TLS on 465"
    },
    {
      "path": [
        "AI",
        "Connection",
        "TLS certificate verified; plaintext refused"
      ],
      "value": "",
      "status": "yes",
      "note": ""
    },
    {
      "path": [
        "AI",
        "Auth",
        "SMTP AUTH with a documented mechanism"
      ],
      "value": "PLAIN over TLS, OAUTHBEARER",
      "status": "yes",
      "note": ""
    },
    {
      "path": [
        "AI",
        "Auth",
        "Credentials never logged"
      ],
      "value": "",
      "status": "yes",
      "note": ""
    },
    {
      "path": [
        "AI",
        "Envelope",
        "MAIL FROM and RCPT TO distinct from header addresses"
      ],
      "value": "",
      "status": "yes",
      "note": "the envelope-vs-header distinction"
    },
    {
      "path": [
        "AI",
        "Envelope",
        "Multiple recipients with per-recipient status"
      ],
      "value": "",
      "status": "yes",
      "note": ""
    },
    {
      "path": [
        "AI",
        "Message",
        "Correct MIME structure for text, HTML and attachments"
      ],
      "value": "",
      "status": "yes",
      "note": ""
    },
    {
      "path": [
        "AI",
        "Message",
        "Header encoding for non-ASCII"
      ],
      "value": "RFC 2047",
      "status": "yes",
      "note": ""
    },
    {
      "path": [
        "AI",
        "Message",
        "Message-ID, Date and required headers present"
      ],
      "value": "",
      "status": "yes",
      "note": ""
    },
    {
      "path": [
        "AI",
        "Deliverability",
        "SPF record authorises the sending host"
      ],
      "value": "",
      "status": "yes",
      "note": ""
    },
    {
      "path": [
        "AI",
        "Deliverability",
        "DKIM signature over stable headers and body"
      ],
      "value": "",
      "status": "yes",
      "note": ""
    },
    {
      "path": [
        "AI",
        "Deliverability",
        "DMARC alignment between From and the authenticated domain"
      ],
      "value": "",
      "status": "yes",
      "note": ""
    },
    {
      "path": [
        "AI",
        "Deliverability",
        "List-Unsubscribe for bulk mail"
      ],
      "value": "",
      "status": "yes",
      "note": "one-click variant"
    },
    {
      "path": [
        "AI",
        "Errors",
        "4xx retried with backoff, 5xx not retried"
      ],
      "value": "",
      "status": "yes",
      "note": "the distinction that matters"
    },
    {
      "path": [
        "AI",
        "Errors",
        "Bounces parsed and the address suppressed"
      ],
      "value": "",
      "status": "yes",
      "note": ""
    },
    {
      "path": [
        "AI",
        "Errors",
        "Rate and concurrency limits respected per destination"
      ],
      "value": "",
      "status": "yes",
      "note": ""
    }
  ]
}