Updating messages

You can rewrite a message after you send it. This powers progress bars (queued, then 40%, then done), and it makes retries harmless. An update always replaces the whole block list. There is no merging and no partial patch. Send the full message again each time.

Give the message a mid

A mid is your own name for a message. It must be unique inside the conversation. Set one, and you can point at that message later.

mid

string

Must match ^[a-zA-Z0-9_.:-]{1,64}$, and be unique per conversation.

Send the same mid again to update

POST to the response_url again with the same mid, and the message is replaced, not copied. The response tells you which one happened:

{
  "ok": true,
  "messages": [{ "message_id": "0f8c", "mid": "job-42", "updated": true }]
}

This is the fix for double messages. If Make or n8n retries a step, the same mid updates instead of posting twice. Put a mid on anything you would hate to see doubled.

A progress loop

Three POSTs to the same response_url, all using mid: "job-42". The visitor sees one bubble change.

{
  "messages": [
    {
      "mid": "job-42",
      "blocks": [{ "type": "status", "state": "pending", "label": "Queued" }]
    }
  ]
}

{
  "messages": [
    {
      "mid": "job-42",
      "blocks": [
        {
          "type": "status",
          "state": "in_progress",
          "label": "Generating your report",
          "progress": 40,
          "detail": "Crunching 3,200 rows"
        }
      ]
    }
  ]
}

{
  "messages": [
    {
      "mid": "job-42",
      "blocks": [
        { "type": "status", "state": "success", "label": "Report ready" },
        { "type": "file", "file_id": "6f1c2a", "name": "june-report.pdf" }
      ]
    }
  ]
}

Pure status and progress changes do not mark the message as edited. Changing other blocks does.

Updating after the 45-minute window

Once the token expires, use an API key. PATCH targets a message by id, with no time limit:

PATCH https://app.my-aichatbot.com/api/v1/messages/{message_id}
Authorization: Bearer mac_live_

curl -X PATCH "https://app.my-aichatbot.com/api/v1/messages/$MESSAGE_ID" \
  -H "Authorization: Bearer $MAC_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "blocks": [{ "type": "status", "state": "success", "label": "Done" }] }'

await fetch(`https://app.my-aichatbot.com/api/v1/messages/${messageId}`, {
  method: 'PATCH',
  headers: {
    Authorization: `Bearer ${process.env.MAC_KEY}`,
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    blocks: [{ type: 'status', state: 'success', label: 'Done' }]
  })
})

requests.patch(
    f"https://app.my-aichatbot.com/api/v1/messages/{message_id}",
    headers={"Authorization": f"Bearer {os.environ['MAC_KEY']}"},
    json={"blocks": [{"type": "status", "state": "success", "label": "Done"}]},
)

$ch = curl_init("https://app.my-aichatbot.com/api/v1/messages/{$messageId}");
curl_setopt_array($ch, [
    CURLOPT_CUSTOMREQUEST => 'PATCH',
    CURLOPT_HTTPHEADER => [
        'Authorization: Bearer ' . getenv('MAC_KEY'),
        'Content-Type: application/json',
    ],
    CURLOPT_POSTFIELDS => json_encode([
        'blocks' => [['type' => 'status', 'state' => 'success', 'label' => 'Done']],
    ]),
    CURLOPT_RETURNTRANSFER => true,
]);
curl_exec($ch);

body, _ := json.Marshal(map[string]any{
    "blocks": []map[string]string{
        {"type": "status", "state": "success", "label": "Done"},
    },
})

req, _ := http.NewRequest("PATCH",
    "https://app.my-aichatbot.com/api/v1/messages/"+messageID,
    bytes.NewReader(body))
req.Header.Set("Authorization", "Bearer "+os.Getenv("MAC_KEY"))
req.Header.Set("Content-Type", "application/json")

resp, err := http.DefaultClient.Do(req)

Response

{ "ok": true, "message_id": "0f8c" }

PATCH takes exactly one message. Sending more than one returns 400 AMBIGUOUS_UPDATE_TARGET.

Rules

Rule	Detail
Bot messages only	Editing a visitor or operator message returns `403 not_bot_authored`.
60 updates per message	Update number 61 returns `429 UPDATE_LIMIT_REACHED`.
Full replacement	Blocks you leave out are removed. Send everything again.
Checked every time	Each update runs the full Block Kit checks.
Frozen after takeover	`409 conversation_taken_over`.

Errors

Status	Code	Meaning
`400`	`AMBIGUOUS_UPDATE_TARGET`	`PATCH` got more than one message.
`403`	`not_bot_authored`	The target is not a bot message.
`404`	`message_not_found`	Unknown message, or it belongs to another bot.
`409`	`conversation_taken_over`	A human took over.
`429`	`UPDATE_LIMIT_REACHED`	Past 60 updates on this message.

Get started

Sending messages

Block Kit

Receiving events

No-code platforms

Give the message a mid

Send the same mid again to update

A progress loop

Updating after the 45-minute window

Rules

Errors

​Give the message a mid

​Send the same mid again to update

​A progress loop

​Updating after the 45-minute window

​Rules

​Errors

Give the message a mid

Send the same mid again to update

A progress loop

Updating after the 45-minute window

Rules

Errors