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Open Swarmhit
Smart APIRaw API
API referenceLinkedin messaging
POST
/api/v1/chats/{id}/messages

A write (message). JSON, or multipart with files. Use unless_replied_since on automated follow-ups. In a Sales Navigator InMail conversation the reply goes through Sales Navigator, text only (a file is 422).

Authorization

X-API-KEY<token>

Your API key from the console (gw_live_…).

In: header

Path Parameters

id*string

A LinkedIn chat id (lgc_…).

Request Body

TypeScript Definitions

Use the request body type in TypeScript.

Response Body

application/json

application/json

application/json

application/json

application/json

application/json

application/json

application/json

application/json

application/json

application/json

curl -X POST "https://example.com/api/v1/chats/lgc_Q2xpZW50Q2hhdA/messages" \  -H "Content-Type: application/json" \  -d '{    "text": "Just following up on my last message.",    "unless_replied_since": "2026-10-28T09:00:00.000Z"  }'
{  "object": "MessageSent",  "chat_id": "lgc_Q2xpZW50Q2hhdA",  "message_id": "lgm_Zm9vYmFyYmF6cXV4",  "id": "lgm_Zm9vYmFyYmF6cXV4",  "timestamp": "2026-10-31T09:30:00.000Z"}

Remove a reaction from a message DELETE

A write (`reaction`), the member's own reaction taken back.

Send a message to a member, or an InMail POST

A message to a connection (in your existing conversation with them when there is one), or an InMail with `linkedin.inmail` (`linkedin[inmail]` in multipart). A Sales Navigator InMail (`linkedin.api: sales_navigator`) goes through the Sales Navigator inbox to the lead's Sales Navigator profile; its `chat_id` is that conversation, which `GET`/`POST /api/v1/chats/{id}/messages` and `PATCH /api/v1/chats/{id}` then read, answer and mark read. A write (`message` or `inmail`). JSON, or multipart with `attachments` / `voice_message` files.