Upsert a Contact
curl --request PUT \
--url https://api.monaco.com/v1/contacts/ \
--header 'Content-Type: application/json' \
--data '
{
"email": "jane@acme.com",
"linkedin_url": "https://linkedin.com/in/janesmith",
"first_name": "Jane",
"last_name": "Smith",
"title": "VP of Engineering",
"phone_number": "+1-415-555-0132",
"location": "San Francisco, CA",
"account_id": "550e8400-e29b-41d4-a716-446655440000",
"domain": "acme.com",
"do_not_contact": false,
"tags": [
"550e8400-e29b-41d4-a716-446655440001"
],
"custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d": "economic_buyer"
}
'import requests
url = "https://api.monaco.com/v1/contacts/"
payload = {
"email": "jane@acme.com",
"linkedin_url": "https://linkedin.com/in/janesmith",
"first_name": "Jane",
"last_name": "Smith",
"title": "VP of Engineering",
"phone_number": "+1-415-555-0132",
"location": "San Francisco, CA",
"account_id": "550e8400-e29b-41d4-a716-446655440000",
"domain": "acme.com",
"do_not_contact": False,
"tags": ["550e8400-e29b-41d4-a716-446655440001"],
"custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d": "economic_buyer"
}
headers = {"Content-Type": "application/json"}
response = requests.put(url, json=payload, headers=headers)
print(response.text)const options = {
method: 'PUT',
headers: {'Content-Type': 'application/json'},
body: JSON.stringify({
email: 'jane@acme.com',
linkedin_url: 'https://linkedin.com/in/janesmith',
first_name: 'Jane',
last_name: 'Smith',
title: 'VP of Engineering',
phone_number: '+1-415-555-0132',
location: 'San Francisco, CA',
account_id: '550e8400-e29b-41d4-a716-446655440000',
domain: 'acme.com',
do_not_contact: false,
tags: ['550e8400-e29b-41d4-a716-446655440001'],
'custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d': 'economic_buyer'
})
};
fetch('https://api.monaco.com/v1/contacts/', 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://api.monaco.com/v1/contacts/",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 30,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "PUT",
CURLOPT_POSTFIELDS => json_encode([
'email' => 'jane@acme.com',
'linkedin_url' => 'https://linkedin.com/in/janesmith',
'first_name' => 'Jane',
'last_name' => 'Smith',
'title' => 'VP of Engineering',
'phone_number' => '+1-415-555-0132',
'location' => 'San Francisco, CA',
'account_id' => '550e8400-e29b-41d4-a716-446655440000',
'domain' => 'acme.com',
'do_not_contact' => false,
'tags' => [
'550e8400-e29b-41d4-a716-446655440001'
],
'custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d' => 'economic_buyer'
]),
CURLOPT_HTTPHEADER => [
"Content-Type: application/json"
],
]);
$response = curl_exec($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://api.monaco.com/v1/contacts/"
payload := strings.NewReader("{\n \"email\": \"jane@acme.com\",\n \"linkedin_url\": \"https://linkedin.com/in/janesmith\",\n \"first_name\": \"Jane\",\n \"last_name\": \"Smith\",\n \"title\": \"VP of Engineering\",\n \"phone_number\": \"+1-415-555-0132\",\n \"location\": \"San Francisco, CA\",\n \"account_id\": \"550e8400-e29b-41d4-a716-446655440000\",\n \"domain\": \"acme.com\",\n \"do_not_contact\": false,\n \"tags\": [\n \"550e8400-e29b-41d4-a716-446655440001\"\n ],\n \"custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d\": \"economic_buyer\"\n}")
req, _ := http.NewRequest("PUT", url, payload)
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.put("https://api.monaco.com/v1/contacts/")
.header("Content-Type", "application/json")
.body("{\n \"email\": \"jane@acme.com\",\n \"linkedin_url\": \"https://linkedin.com/in/janesmith\",\n \"first_name\": \"Jane\",\n \"last_name\": \"Smith\",\n \"title\": \"VP of Engineering\",\n \"phone_number\": \"+1-415-555-0132\",\n \"location\": \"San Francisco, CA\",\n \"account_id\": \"550e8400-e29b-41d4-a716-446655440000\",\n \"domain\": \"acme.com\",\n \"do_not_contact\": false,\n \"tags\": [\n \"550e8400-e29b-41d4-a716-446655440001\"\n ],\n \"custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d\": \"economic_buyer\"\n}")
.asString();require 'uri'
require 'net/http'
url = URI("https://api.monaco.com/v1/contacts/")
http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
request = Net::HTTP::Put.new(url)
request["Content-Type"] = 'application/json'
request.body = "{\n \"email\": \"jane@acme.com\",\n \"linkedin_url\": \"https://linkedin.com/in/janesmith\",\n \"first_name\": \"Jane\",\n \"last_name\": \"Smith\",\n \"title\": \"VP of Engineering\",\n \"phone_number\": \"+1-415-555-0132\",\n \"location\": \"San Francisco, CA\",\n \"account_id\": \"550e8400-e29b-41d4-a716-446655440000\",\n \"domain\": \"acme.com\",\n \"do_not_contact\": false,\n \"tags\": [\n \"550e8400-e29b-41d4-a716-446655440001\"\n ],\n \"custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d\": \"economic_buyer\"\n}"
response = http.request(request)
puts response.read_body{
"data": {
"id": "con_abc123",
"account_id": "acc_def456",
"first_name": "Jane",
"last_name": "Smith",
"email": "jane@acme.com",
"title": "VP of Engineering",
"phone_number": "+1-415-555-0132",
"linkedin_url": "https://linkedin.com/in/janesmith",
"location": "San Francisco, CA",
"source": "api",
"do_not_contact": false,
"notes": "Met at SaaStr 2025",
"scoring": {
"heat_score": "Hot"
},
"tags": [
"Decision Maker"
],
"created_at": "2025-06-15T10:30:00Z",
"updated_at": "2026-04-21T12:00:00Z",
"custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d": "economic_buyer"
},
"meta": {
"timestamp": "2026-04-21T12:00:00Z"
}
}{
"error": {
"code": "not_found",
"message": "Resource not found"
}
}Contacts
Upsert a Contact
Creates a new contact or updates an existing one.
Identifiers — with only linkedin_url, also pass account_id or domain.
Duplicate resolution — matched against existing contacts by email (case-insensitive), then linkedin_url. A match is updated in place, otherwise a contact is created. Unlike POST /contacts, a duplicate identifier is not a 409. The exception: if the identifiers resolve to two different contacts on the same account, neither can be updated and a 409 is returned.
Account resolution priority — when creating: account_id, then domain, then the domain parsed from email.
Enrichment — creating a contact synchronously enriches it and resolves or creates its account, so those requests can take several seconds. Use generous timeouts (10s+) and keep upserts off hot paths.
PUT
/
v1
/
contacts
/
Upsert a Contact
curl --request PUT \
--url https://api.monaco.com/v1/contacts/ \
--header 'Content-Type: application/json' \
--data '
{
"email": "jane@acme.com",
"linkedin_url": "https://linkedin.com/in/janesmith",
"first_name": "Jane",
"last_name": "Smith",
"title": "VP of Engineering",
"phone_number": "+1-415-555-0132",
"location": "San Francisco, CA",
"account_id": "550e8400-e29b-41d4-a716-446655440000",
"domain": "acme.com",
"do_not_contact": false,
"tags": [
"550e8400-e29b-41d4-a716-446655440001"
],
"custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d": "economic_buyer"
}
'import requests
url = "https://api.monaco.com/v1/contacts/"
payload = {
"email": "jane@acme.com",
"linkedin_url": "https://linkedin.com/in/janesmith",
"first_name": "Jane",
"last_name": "Smith",
"title": "VP of Engineering",
"phone_number": "+1-415-555-0132",
"location": "San Francisco, CA",
"account_id": "550e8400-e29b-41d4-a716-446655440000",
"domain": "acme.com",
"do_not_contact": False,
"tags": ["550e8400-e29b-41d4-a716-446655440001"],
"custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d": "economic_buyer"
}
headers = {"Content-Type": "application/json"}
response = requests.put(url, json=payload, headers=headers)
print(response.text)const options = {
method: 'PUT',
headers: {'Content-Type': 'application/json'},
body: JSON.stringify({
email: 'jane@acme.com',
linkedin_url: 'https://linkedin.com/in/janesmith',
first_name: 'Jane',
last_name: 'Smith',
title: 'VP of Engineering',
phone_number: '+1-415-555-0132',
location: 'San Francisco, CA',
account_id: '550e8400-e29b-41d4-a716-446655440000',
domain: 'acme.com',
do_not_contact: false,
tags: ['550e8400-e29b-41d4-a716-446655440001'],
'custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d': 'economic_buyer'
})
};
fetch('https://api.monaco.com/v1/contacts/', 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://api.monaco.com/v1/contacts/",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 30,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "PUT",
CURLOPT_POSTFIELDS => json_encode([
'email' => 'jane@acme.com',
'linkedin_url' => 'https://linkedin.com/in/janesmith',
'first_name' => 'Jane',
'last_name' => 'Smith',
'title' => 'VP of Engineering',
'phone_number' => '+1-415-555-0132',
'location' => 'San Francisco, CA',
'account_id' => '550e8400-e29b-41d4-a716-446655440000',
'domain' => 'acme.com',
'do_not_contact' => false,
'tags' => [
'550e8400-e29b-41d4-a716-446655440001'
],
'custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d' => 'economic_buyer'
]),
CURLOPT_HTTPHEADER => [
"Content-Type: application/json"
],
]);
$response = curl_exec($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://api.monaco.com/v1/contacts/"
payload := strings.NewReader("{\n \"email\": \"jane@acme.com\",\n \"linkedin_url\": \"https://linkedin.com/in/janesmith\",\n \"first_name\": \"Jane\",\n \"last_name\": \"Smith\",\n \"title\": \"VP of Engineering\",\n \"phone_number\": \"+1-415-555-0132\",\n \"location\": \"San Francisco, CA\",\n \"account_id\": \"550e8400-e29b-41d4-a716-446655440000\",\n \"domain\": \"acme.com\",\n \"do_not_contact\": false,\n \"tags\": [\n \"550e8400-e29b-41d4-a716-446655440001\"\n ],\n \"custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d\": \"economic_buyer\"\n}")
req, _ := http.NewRequest("PUT", url, payload)
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.put("https://api.monaco.com/v1/contacts/")
.header("Content-Type", "application/json")
.body("{\n \"email\": \"jane@acme.com\",\n \"linkedin_url\": \"https://linkedin.com/in/janesmith\",\n \"first_name\": \"Jane\",\n \"last_name\": \"Smith\",\n \"title\": \"VP of Engineering\",\n \"phone_number\": \"+1-415-555-0132\",\n \"location\": \"San Francisco, CA\",\n \"account_id\": \"550e8400-e29b-41d4-a716-446655440000\",\n \"domain\": \"acme.com\",\n \"do_not_contact\": false,\n \"tags\": [\n \"550e8400-e29b-41d4-a716-446655440001\"\n ],\n \"custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d\": \"economic_buyer\"\n}")
.asString();require 'uri'
require 'net/http'
url = URI("https://api.monaco.com/v1/contacts/")
http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
request = Net::HTTP::Put.new(url)
request["Content-Type"] = 'application/json'
request.body = "{\n \"email\": \"jane@acme.com\",\n \"linkedin_url\": \"https://linkedin.com/in/janesmith\",\n \"first_name\": \"Jane\",\n \"last_name\": \"Smith\",\n \"title\": \"VP of Engineering\",\n \"phone_number\": \"+1-415-555-0132\",\n \"location\": \"San Francisco, CA\",\n \"account_id\": \"550e8400-e29b-41d4-a716-446655440000\",\n \"domain\": \"acme.com\",\n \"do_not_contact\": false,\n \"tags\": [\n \"550e8400-e29b-41d4-a716-446655440001\"\n ],\n \"custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d\": \"economic_buyer\"\n}"
response = http.request(request)
puts response.read_body{
"data": {
"id": "con_abc123",
"account_id": "acc_def456",
"first_name": "Jane",
"last_name": "Smith",
"email": "jane@acme.com",
"title": "VP of Engineering",
"phone_number": "+1-415-555-0132",
"linkedin_url": "https://linkedin.com/in/janesmith",
"location": "San Francisco, CA",
"source": "api",
"do_not_contact": false,
"notes": "Met at SaaStr 2025",
"scoring": {
"heat_score": "Hot"
},
"tags": [
"Decision Maker"
],
"created_at": "2025-06-15T10:30:00Z",
"updated_at": "2026-04-21T12:00:00Z",
"custom_field_1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d": "economic_buyer"
},
"meta": {
"timestamp": "2026-04-21T12:00:00Z"
}
}{
"error": {
"code": "not_found",
"message": "Resource not found"
}
}Body
application/json
Request body for creating a contact via POST or upserting via PUT.
Custom fields can be passed as additional keys prefixed with custom_field_.
Whether the contact is an inbound lead. When true and this request creates a new contact, Monaco runs inbound-lead qualification on it. Ignored when the request matches an existing contact.
Email address of the contact. Either email or linkedin_url is required.
Example:
"jane@acme.com"
LinkedIn profile URL (a linkedin.com/in/... URL). Either email or linkedin_url is required.
Example:
"https://linkedin.com/in/janesmith"
First name of the contact
Example:
"Jane"
Last name of the contact
Example:
"Smith"
Job title of the contact
Example:
"VP of Engineering"
Phone number of the contact
Example:
"+1-415-555-0132"
Location of the contact
Example:
"San Francisco, CA"
ID of the account to associate the contact with
Domain of the contact's company (used for account resolution)
Example:
"acme.com"
Whether the contact has opted out of outreach
Notes about the contact
Example:
"Met at conference in 2025"
Tag IDs to associate with the contact. Appended to the contact's existing tags.