{
  "id": "MSG-011",
  "slug": "msg-011",
  "title": "Opt-out confirmation must be 20–255 characters",
  "statement": "The STOP confirmation must be at least 20 and at most 255 characters.",
  "rationale": "This is the last message you are permitted to send, so it must fit in one segment and say everything it needs to in one pass. A truncated opt-out confirmation can lose the acknowledgement itself, leaving the consumer unsure whether the unsubscribe worked.",
  "layer": "MESSAGE_CONTENT",
  "layerSlug": "message-content",
  "object": "campaign.optout_message",
  "severity": "BLOCKING",
  "detectability": [
    "DETERMINISTIC"
  ],
  "failureClass": "RETRY_FIELD",
  "authorities": [
    "TCR",
    "Twilio",
    "Bird",
    "Sinch"
  ],
  "applicabilityText": "Applies to every 10DLC registration.",
  "universal": true,
  "remediation": "Fit the confirmation into 255 characters: brand name, the acknowledgement, and that no further messages will be sent.",
  "example": "Acme Coffee: you have been unsubscribed and will receive no further messages. Reply HELP for help.",
  "phase": "approval",
  "automated": true,
  "url": "https://ekas.io/rules/10dlc/message-content/msg-011/",
  "markdown": "https://ekas.io/rules/10dlc/message-content/msg-011.md",
  "registry": "https://ekas.io/rules/10dlc/",
  "updated": "2026-07-25",
  "licence": "CC BY 4.0 — https://creativecommons.org/licenses/by/4.0/"
}