Send a message to an existing chat
Send a message to an existing chat. Use this endpoint when you already have a chat ID and want to send additional messages to it.
Message Effects
You can add iMessage effects to make your messages more expressive. Effects are optional and can be either screen effects (full-screen animations) or bubble effects (message bubble animations).
Screen Effects: confetti, fireworks, lasers, sparkles, celebration,
hearts, love, balloons, happy_birthday, echo, spotlight
Bubble Effects: slam, loud, gentle, invisible
Only one effect type can be applied per message.
Inline Text Decorations (iMessage only)
Use the text_decorations array on a text part to apply styling and animations to character ranges.
Each decoration specifies a range: [start, end) and exactly one of style or animation.
Styles: bold, italic, strikethrough, underline
Animations: big, small, shake, nod, explode, ripple, bloom, jitter
{
"type": "text",
"value": "Hello world",
"text_decorations": [
{ "range": [0, 5], "style": "bold" },
{ "range": [6, 11], "animation": "shake" }
]
}Note: Style ranges (bold, italic, etc.) may overlap, but animation ranges must not overlap with other animations or styles. Text decorations only render for iMessage recipients. For SMS/RCS, text decorations are not applied.
Send a message to an existing chat
curl https://api.linqapp.com/api/partner/v3/chats/$CHAT_ID/messages \
-H 'Content-Type: application/json' \
-H "Authorization: Bearer $LINQ_API_V3_API_KEY" \
-d '{
"message": {
"parts": [
{
"type": "text",
"value": "Hello, world!"
}
]
}
}'{
"chat_id": "550e8400-e29b-41d4-a716-446655440000",
"message": {
"id": "69a37c7d-af4f-4b5e-af42-e28e98ce873a",
"created_at": "2025-10-23T13:07:55.019-05:00",
"delivery_status": "pending",
"is_read": false,
"parts": [
{
"reactions": [
{
"handle": {
"id": "69a37c7d-af4f-4b5e-af42-e28e98ce873a",
"handle": "+15551234567",
"joined_at": "2025-05-21T15:30:00.000-05:00",
"service": "iMessage",
"is_me": false,
"left_at": "2019-12-27T18:11:19.117Z",
"status": "active"
},
"is_me": false,
"type": "love",
"custom_emoji": null,
"sticker": {
"file_name": "sticker.png",
"height": 420,
"mime_type": "image/png",
"url": "https://cdn.linqapp.com/attachments/a1b2c3d4/sticker.png?signature=...",
"width": 420
}
}
],
"type": "text",
"value": "Hello!",
"text_decorations": [
{
"range": [
0,
5
],
"animation": "shake",
"style": "bold"
}
]
}
],
"sent_at": null,
"delivered_at": null,
"effect": {
"name": "confetti",
"type": "screen"
},
"from_handle": {
"id": "550e8400-e29b-41d4-a716-446655440000",
"handle": "+15551234567",
"joined_at": "2025-05-21T15:30:00.000-05:00",
"service": "iMessage",
"is_me": false,
"left_at": "2019-12-27T18:11:19.117Z",
"status": "active"
},
"preferred_service": "iMessage",
"reply_to": {
"message_id": "550e8400-e29b-41d4-a716-446655440000",
"part_index": 0
},
"service": "iMessage"
}
}{
"error": {
"status": 400,
"code": 1002,
"message": "Phone number must be in E.164 format"
},
"success": false
}{
"error": {
"status": 401,
"code": 2004,
"message": "Unauthorized - missing or invalid authentication token"
},
"success": false
}{
"error": {
"status": 404,
"code": 2001,
"message": "Resource not found"
},
"success": false
}{
"error": {
"status": 500,
"code": 3006,
"message": "Internal server error"
},
"success": false
}Returns Examples
{
"chat_id": "550e8400-e29b-41d4-a716-446655440000",
"message": {
"id": "69a37c7d-af4f-4b5e-af42-e28e98ce873a",
"created_at": "2025-10-23T13:07:55.019-05:00",
"delivery_status": "pending",
"is_read": false,
"parts": [
{
"reactions": [
{
"handle": {
"id": "69a37c7d-af4f-4b5e-af42-e28e98ce873a",
"handle": "+15551234567",
"joined_at": "2025-05-21T15:30:00.000-05:00",
"service": "iMessage",
"is_me": false,
"left_at": "2019-12-27T18:11:19.117Z",
"status": "active"
},
"is_me": false,
"type": "love",
"custom_emoji": null,
"sticker": {
"file_name": "sticker.png",
"height": 420,
"mime_type": "image/png",
"url": "https://cdn.linqapp.com/attachments/a1b2c3d4/sticker.png?signature=...",
"width": 420
}
}
],
"type": "text",
"value": "Hello!",
"text_decorations": [
{
"range": [
0,
5
],
"animation": "shake",
"style": "bold"
}
]
}
],
"sent_at": null,
"delivered_at": null,
"effect": {
"name": "confetti",
"type": "screen"
},
"from_handle": {
"id": "550e8400-e29b-41d4-a716-446655440000",
"handle": "+15551234567",
"joined_at": "2025-05-21T15:30:00.000-05:00",
"service": "iMessage",
"is_me": false,
"left_at": "2019-12-27T18:11:19.117Z",
"status": "active"
},
"preferred_service": "iMessage",
"reply_to": {
"message_id": "550e8400-e29b-41d4-a716-446655440000",
"part_index": 0
},
"service": "iMessage"
}
}{
"error": {
"status": 400,
"code": 1002,
"message": "Phone number must be in E.164 format"
},
"success": false
}{
"error": {
"status": 401,
"code": 2004,
"message": "Unauthorized - missing or invalid authentication token"
},
"success": false
}{
"error": {
"status": 404,
"code": 2001,
"message": "Resource not found"
},
"success": false
}{
"error": {
"status": 500,
"code": 3006,
"message": "Internal server error"
},
"success": false
}