Reactions

React to any WhatsApp message with a single emoji — or receive reactions from your contacts as inbound webhook events. Full parity with WhatsApp Web’s reaction UI.

Concepts

A reaction is a single emoji tied to a parent message (a message that already exists in the WhatsApp conversation and has a waMessageId). Meta enforces:

One reaction per person per message. Reacting again with a different emoji replaces the previous one. Reacting with an empty string "" removes the current reaction.
Same 24-hour window as messages (aka the CSW). A reaction sent more than 24h after the last inbound from the contact will be rejected with error 131047 — same behavior as free-form text outside the window. Reactions on messages inside the window work regardless of how old the parent is.
Reactions do not open a new conversation. They don’t consume a billable conversation from Meta.

Sending a reaction

{id} is the internal GoSendAPI message ID (from the id field of a previous POST /v1/messages response, or from a messages webhook). NOT the waMessageId.

curl https://cloud.gosendapi.com/v1/messages/{id}/reactions \
  -X POST \
  -H "X-API-Key: gsk_live_..." \
  -H "Content-Type: application/json" \
  -d '{ "emoji": "❤️" }'

Response:

{ "ok": true }

Removing a reaction

Send an empty string:

curl https://cloud.gosendapi.com/v1/messages/{id}/reactions \
  -X POST \
  -H "X-API-Key: gsk_live_..." \
  -H "Content-Type: application/json" \
  -d '{ "emoji": "" }'

Response:

{ "ok": true, "deleted": true }

Idempotency

Reacting twice with the same emoji is a no-op. Changing the emoji replaces the previous reaction (no duplicate row). You don’t need an Idempotency-Key header for reactions — the underlying store is upsert-by-(message, sender).

Errors

Code	Meaning	What to do
`131047`	Reaction outside 24h window	Send a template first to reopen the CSW, then react.
`100`	Invalid parent message	The parent has no `waMessageId` yet (still sending) or was deleted from Meta. Wait or refetch.
`400 emoji required`	Body missing `emoji` field	Send `{ "emoji": "..." }`. Empty string = remove.
`404 Message not found`	The `{id}` doesn’t belong to your project	Check the ID from your DB / previous response.

Meta’s own error codes are documented in the WhatsApp Cloud API error reference.

Receiving reactions

Reactions from your contacts arrive as regular messages webhook events with type: "reaction":

{
  "messaging_product": "whatsapp",
  "entry": [{
    "changes": [{
      "field": "messages",
      "value": {
        "messages": [{
          "id": "wamid.ABC...",
          "from": "5491122334455",
          "timestamp": "1732300000",
          "type": "reaction",
          "reaction": {
            "message_id": "wamid.PARENT...",
            "emoji": "👍"
          }
        }]
      }
    }]
  }]
}

Notes:

message_id is the waMessageId of the parent (the message they reacted to). To find your internal message, look it up by waMessageId.
An empty emoji means the contact removed their reaction.
Reactions are also persisted internally — the GET /v1/messages list endpoints expose them under each parent message’s reactions field.

Coexistence

If your customer is on WhatsApp Business coexistence mode (also using the WhatsApp Business app on their phone), reactions sent from the phone arrive to you as smb_message_echoes webhook events with the same type: "reaction" shape. They’re persisted alongside API-sent reactions — the portal UI distinguishes them (mine=true when the reaction came from the business’s own WhatsApp number).

In the portal & embed

Both the main portal inbox (/app/inbox) and the embed inbox render reactions as chips under the bubble. Users can pick from a set of quick emojis or your own reaction (green chip) to remove it. Errors show an inline banner instead of a crude alert — the CSW rejection specifically offers “Send template” to reopen the window.

Sending messages Webhooks