Send LinkedIn message

curl --request POST \
  --url https://app.gtm-api.com/linkedin/v4/api/linkedin-messages/send \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'Team-SID: <api-key>' \
  --data '
{
  "linkedin_account_sid": "<string>",
  "text": "<string>",
  "linkedin_conversation_sid": "<string>",
  "ln_id": "<string>",
  "sn_id": "<string>",
  "attachments": [
    {
      "name": "<string>",
      "path": "<string>",
      "size": 1
    }
  ]
}
'

import requests

url = "https://app.gtm-api.com/linkedin/v4/api/linkedin-messages/send"

payload = {
    "linkedin_account_sid": "<string>",
    "text": "<string>",
    "linkedin_conversation_sid": "<string>",
    "ln_id": "<string>",
    "sn_id": "<string>",
    "attachments": [
        {
            "name": "<string>",
            "path": "<string>",
            "size": 1
        }
    ]
}
headers = {
    "Authorization": "Bearer <token>",
    "Team-SID": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {
    Authorization: 'Bearer <token>',
    'Team-SID': '<api-key>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    linkedin_account_sid: '<string>',
    text: '<string>',
    linkedin_conversation_sid: '<string>',
    ln_id: '<string>',
    sn_id: '<string>',
    attachments: [{name: '<string>', path: '<string>', size: 1}]
  })
};

fetch('https://app.gtm-api.com/linkedin/v4/api/linkedin-messages/send', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://app.gtm-api.com/linkedin/v4/api/linkedin-messages/send",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'linkedin_account_sid' => '<string>',
    'text' => '<string>',
    'linkedin_conversation_sid' => '<string>',
    'ln_id' => '<string>',
    'sn_id' => '<string>',
    'attachments' => [
        [
                'name' => '<string>',
                'path' => '<string>',
                'size' => 1
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json",
    "Team-SID: <api-key>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://app.gtm-api.com/linkedin/v4/api/linkedin-messages/send"

	payload := strings.NewReader("{\n  \"linkedin_account_sid\": \"<string>\",\n  \"text\": \"<string>\",\n  \"linkedin_conversation_sid\": \"<string>\",\n  \"ln_id\": \"<string>\",\n  \"sn_id\": \"<string>\",\n  \"attachments\": [\n    {\n      \"name\": \"<string>\",\n      \"path\": \"<string>\",\n      \"size\": 1\n    }\n  ]\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Team-SID", "<api-key>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://app.gtm-api.com/linkedin/v4/api/linkedin-messages/send")
  .header("Authorization", "Bearer <token>")
  .header("Team-SID", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"linkedin_account_sid\": \"<string>\",\n  \"text\": \"<string>\",\n  \"linkedin_conversation_sid\": \"<string>\",\n  \"ln_id\": \"<string>\",\n  \"sn_id\": \"<string>\",\n  \"attachments\": [\n    {\n      \"name\": \"<string>\",\n      \"path\": \"<string>\",\n      \"size\": 1\n    }\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://app.gtm-api.com/linkedin/v4/api/linkedin-messages/send")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Team-SID"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"linkedin_account_sid\": \"<string>\",\n  \"text\": \"<string>\",\n  \"linkedin_conversation_sid\": \"<string>\",\n  \"ln_id\": \"<string>\",\n  \"sn_id\": \"<string>\",\n  \"attachments\": [\n    {\n      \"name\": \"<string>\",\n      \"path\": \"<string>\",\n      \"size\": 1\n    }\n  ]\n}"

response = http.request(request)
puts response.read_body

{
  "success": true,
  "operation": "action",
  "action": "<string>",
  "item": {
    "sid": "<string>",
    "team_sid": "<string>",
    "linkedin_account_sid": "<string>",
    "linkedin_conversation_sid": "<string>",
    "ln_member_id": "<string>",
    "ln_id": "<string>",
    "sn_id": "<string>",
    "nickname": "<string>",
    "subject": "<string>",
    "text": "<string>",
    "attachments": [
      {
        "id": "<string>",
        "urn": "<string>",
        "name": "<string>",
        "content_type": "<string>",
        "content_url": "<string>",
        "file_byte_size": 123,
        "path": "<string>",
        "size": 123
      }
    ],
    "reactions": [
      {
        "emoji": "<string>",
        "count": 123,
        "is_viewer_reacted": true,
        "first_reacted_at": "<string>"
      }
    ],
    "message_hash": "<string>",
    "sent_at": "<string>",
    "custom_content": {},
    "created_at": "<string>",
    "updated_at": "<string>",
    "deleted_at": "<string>"
  },
  "result": {},
  "meta": {
    "trace_id": "<string>",
    "span_id": "<string>",
    "timestamp": "<string>",
    "duration_ms": 1,
    "debug_url": "<string>"
  },
  "credits": {
    "charged": 1,
    "balance_after": 1
  }
}

{
  "success": false,
  "error": {
    "message": "<string>",
    "recoverable": true,
    "suggestion": "<string>",
    "field_errors": {},
    "blockers": [
      {
        "type": "<string>",
        "description": "<string>",
        "entity_sid": "<string>",
        "resolution": "<string>",
        "resolution_hint": "<string>",
        "count": 123
      }
    ],
    "context": {}
  },
  "meta": {
    "trace_id": "<string>",
    "span_id": "<string>",
    "timestamp": "<string>",
    "duration_ms": 1,
    "debug_url": "<string>"
  }
}

{
  "success": false,
  "error": {
    "message": "<string>",
    "recoverable": true,
    "suggestion": "<string>",
    "field_errors": {},
    "blockers": [
      {
        "type": "<string>",
        "description": "<string>",
        "entity_sid": "<string>",
        "resolution": "<string>",
        "resolution_hint": "<string>",
        "count": 123
      }
    ],
    "context": {}
  },
  "meta": {
    "trace_id": "<string>",
    "span_id": "<string>",
    "timestamp": "<string>",
    "duration_ms": 1,
    "debug_url": "<string>"
  }
}

linkedin_messages

Send LinkedIn message

Send one outbound regular LinkedIn DM on the basic messenger (outward action). Reply to an existing thread via linkedin_conversation_sid, or open a new thread to a 1st-degree connection via ln_id / sn_id. Guards run first: in-flight dedup, send_messages daily cap, 8000-char body cap, connection guard, attachment https:// reachability, basic-messenger surface guard. Fire-on-success: a row is inserted only on terminal success. When NOT: InMail to a non-connection → send_linkedin_inmail; voice note → send_linkedin_voice_message; Sales Navigator thread → send_linkedin_sales_nav_message; the connection-request note lives on linkedin-connection-requests. Bulk send: loop client-side and respect the daily cap.

Contract:

MCP tool send_linkedin_message, registry package mcp.linkedin/linkedin_messages, mount linkedin.messaging.
Operation action, response envelope action.
Flags: dangerous: the MCP layer gates it behind a preview/commit token, and the effect cannot be undone through this API.

POST

api

linkedin-messages

send

Send LinkedIn message

curl --request POST \
  --url https://app.gtm-api.com/linkedin/v4/api/linkedin-messages/send \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'Team-SID: <api-key>' \
  --data '
{
  "linkedin_account_sid": "<string>",
  "text": "<string>",
  "linkedin_conversation_sid": "<string>",
  "ln_id": "<string>",
  "sn_id": "<string>",
  "attachments": [
    {
      "name": "<string>",
      "path": "<string>",
      "size": 1
    }
  ]
}
'

import requests

url = "https://app.gtm-api.com/linkedin/v4/api/linkedin-messages/send"

payload = {
    "linkedin_account_sid": "<string>",
    "text": "<string>",
    "linkedin_conversation_sid": "<string>",
    "ln_id": "<string>",
    "sn_id": "<string>",
    "attachments": [
        {
            "name": "<string>",
            "path": "<string>",
            "size": 1
        }
    ]
}
headers = {
    "Authorization": "Bearer <token>",
    "Team-SID": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {
    Authorization: 'Bearer <token>',
    'Team-SID': '<api-key>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    linkedin_account_sid: '<string>',
    text: '<string>',
    linkedin_conversation_sid: '<string>',
    ln_id: '<string>',
    sn_id: '<string>',
    attachments: [{name: '<string>', path: '<string>', size: 1}]
  })
};

fetch('https://app.gtm-api.com/linkedin/v4/api/linkedin-messages/send', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://app.gtm-api.com/linkedin/v4/api/linkedin-messages/send",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'linkedin_account_sid' => '<string>',
    'text' => '<string>',
    'linkedin_conversation_sid' => '<string>',
    'ln_id' => '<string>',
    'sn_id' => '<string>',
    'attachments' => [
        [
                'name' => '<string>',
                'path' => '<string>',
                'size' => 1
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json",
    "Team-SID: <api-key>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://app.gtm-api.com/linkedin/v4/api/linkedin-messages/send"

	payload := strings.NewReader("{\n  \"linkedin_account_sid\": \"<string>\",\n  \"text\": \"<string>\",\n  \"linkedin_conversation_sid\": \"<string>\",\n  \"ln_id\": \"<string>\",\n  \"sn_id\": \"<string>\",\n  \"attachments\": [\n    {\n      \"name\": \"<string>\",\n      \"path\": \"<string>\",\n      \"size\": 1\n    }\n  ]\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Team-SID", "<api-key>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://app.gtm-api.com/linkedin/v4/api/linkedin-messages/send")
  .header("Authorization", "Bearer <token>")
  .header("Team-SID", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"linkedin_account_sid\": \"<string>\",\n  \"text\": \"<string>\",\n  \"linkedin_conversation_sid\": \"<string>\",\n  \"ln_id\": \"<string>\",\n  \"sn_id\": \"<string>\",\n  \"attachments\": [\n    {\n      \"name\": \"<string>\",\n      \"path\": \"<string>\",\n      \"size\": 1\n    }\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://app.gtm-api.com/linkedin/v4/api/linkedin-messages/send")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Team-SID"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"linkedin_account_sid\": \"<string>\",\n  \"text\": \"<string>\",\n  \"linkedin_conversation_sid\": \"<string>\",\n  \"ln_id\": \"<string>\",\n  \"sn_id\": \"<string>\",\n  \"attachments\": [\n    {\n      \"name\": \"<string>\",\n      \"path\": \"<string>\",\n      \"size\": 1\n    }\n  ]\n}"

response = http.request(request)
puts response.read_body

{
  "success": true,
  "operation": "action",
  "action": "<string>",
  "item": {
    "sid": "<string>",
    "team_sid": "<string>",
    "linkedin_account_sid": "<string>",
    "linkedin_conversation_sid": "<string>",
    "ln_member_id": "<string>",
    "ln_id": "<string>",
    "sn_id": "<string>",
    "nickname": "<string>",
    "subject": "<string>",
    "text": "<string>",
    "attachments": [
      {
        "id": "<string>",
        "urn": "<string>",
        "name": "<string>",
        "content_type": "<string>",
        "content_url": "<string>",
        "file_byte_size": 123,
        "path": "<string>",
        "size": 123
      }
    ],
    "reactions": [
      {
        "emoji": "<string>",
        "count": 123,
        "is_viewer_reacted": true,
        "first_reacted_at": "<string>"
      }
    ],
    "message_hash": "<string>",
    "sent_at": "<string>",
    "custom_content": {},
    "created_at": "<string>",
    "updated_at": "<string>",
    "deleted_at": "<string>"
  },
  "result": {},
  "meta": {
    "trace_id": "<string>",
    "span_id": "<string>",
    "timestamp": "<string>",
    "duration_ms": 1,
    "debug_url": "<string>"
  },
  "credits": {
    "charged": 1,
    "balance_after": 1
  }
}

{
  "success": false,
  "error": {
    "message": "<string>",
    "recoverable": true,
    "suggestion": "<string>",
    "field_errors": {},
    "blockers": [
      {
        "type": "<string>",
        "description": "<string>",
        "entity_sid": "<string>",
        "resolution": "<string>",
        "resolution_hint": "<string>",
        "count": 123
      }
    ],
    "context": {}
  },
  "meta": {
    "trace_id": "<string>",
    "span_id": "<string>",
    "timestamp": "<string>",
    "duration_ms": 1,
    "debug_url": "<string>"
  }
}

{
  "success": false,
  "error": {
    "message": "<string>",
    "recoverable": true,
    "suggestion": "<string>",
    "field_errors": {},
    "blockers": [
      {
        "type": "<string>",
        "description": "<string>",
        "entity_sid": "<string>",
        "resolution": "<string>",
        "resolution_hint": "<string>",
        "count": 123
      }
    ],
    "context": {}
  },
  "meta": {
    "trace_id": "<string>",
    "span_id": "<string>",
    "timestamp": "<string>",
    "duration_ms": 1,
    "debug_url": "<string>"
  }
}

Authorizations

Authorization

string

header

required

Access token issued by gtm.service.id. Its access_identity claim carries team_sid, actor_sid and actor_type, and that team scope is authoritative.

Team-SID

string

header

required

Team scope for tokens that do not carry one. Ignored when the token already names a team.

Body

application/json

Request body of send_linkedin_message.

linkedin_account_sid

string

required

LinkedIn account sid (ln_ac_…).

Required string length: 18

Pattern: ^ln_ac_

text

string

required

Message body; 1..8000 chars.

Required string length: 1 - 8000

linkedin_conversation_sid

string | null

Existing basic-messenger thread; provide this OR a profile URN.

Required string length: 18

Pattern: ^ln_cv_

ln_id

string | null

Regular-profile URN (ACoAA…) for a new thread.

Maximum string length: 128

sn_id

string | null

Sales Navigator URN (ACwAA…); interchangeable with ln_id.

Maximum string length: 64

attachments

object[]

Each .path must be an https:// URL.

Show child attributes

Response

action success envelope.

success

enum<boolean>

required

Available options:

true

operation

enum<string>

required

Available options:

action

action

string

required

kebab-case verb; matches the route segment.

item

object | null

required

Show child attributes

result

object

required

Show child attributes

Overview

LinkedIn API

ID and Teams API

Orchestration API

Send LinkedIn message

Authorizations

Body

Response