curl --request POST \
--url https://api.contourvoice.com/v1/calls \
--header 'Authorization: Bearer <token>' \
--header 'Content-Type: application/json' \
--data '
{
"agent_id": "3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f",
"from_number": "+15555550199",
"metadata": {
"your_order_id": "ORD-8812"
},
"to_number": "+15555550100",
"variables": {
"appointment_date": "2026-09-15",
"patient_name": "Jane Doe"
}
}
'import requests
url = "https://api.contourvoice.com/v1/calls"
payload = {
"agent_id": "3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f",
"from_number": "+15555550199",
"metadata": { "your_order_id": "ORD-8812" },
"to_number": "+15555550100",
"variables": {
"appointment_date": "2026-09-15",
"patient_name": "Jane Doe"
}
}
headers = {
"Authorization": "Bearer <token>",
"Content-Type": "application/json"
}
response = requests.post(url, json=payload, headers=headers)
print(response.text)const options = {
method: 'POST',
headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
body: JSON.stringify({
agent_id: '3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f',
from_number: '+15555550199',
metadata: {your_order_id: 'ORD-8812'},
to_number: '+15555550100',
variables: {appointment_date: '2026-09-15', patient_name: 'Jane Doe'}
})
};
fetch('https://api.contourvoice.com/v1/calls', 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.contourvoice.com/v1/calls",
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([
'agent_id' => '3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f',
'from_number' => '+15555550199',
'metadata' => [
'your_order_id' => 'ORD-8812'
],
'to_number' => '+15555550100',
'variables' => [
'appointment_date' => '2026-09-15',
'patient_name' => 'Jane Doe'
]
]),
CURLOPT_HTTPHEADER => [
"Authorization: Bearer <token>",
"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.contourvoice.com/v1/calls"
payload := strings.NewReader("{\n \"agent_id\": \"3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f\",\n \"from_number\": \"+15555550199\",\n \"metadata\": {\n \"your_order_id\": \"ORD-8812\"\n },\n \"to_number\": \"+15555550100\",\n \"variables\": {\n \"appointment_date\": \"2026-09-15\",\n \"patient_name\": \"Jane Doe\"\n }\n}")
req, _ := http.NewRequest("POST", url, payload)
req.Header.Add("Authorization", "Bearer <token>")
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://api.contourvoice.com/v1/calls")
.header("Authorization", "Bearer <token>")
.header("Content-Type", "application/json")
.body("{\n \"agent_id\": \"3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f\",\n \"from_number\": \"+15555550199\",\n \"metadata\": {\n \"your_order_id\": \"ORD-8812\"\n },\n \"to_number\": \"+15555550100\",\n \"variables\": {\n \"appointment_date\": \"2026-09-15\",\n \"patient_name\": \"Jane Doe\"\n }\n}")
.asString();require 'uri'
require 'net/http'
url = URI("https://api.contourvoice.com/v1/calls")
http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n \"agent_id\": \"3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f\",\n \"from_number\": \"+15555550199\",\n \"metadata\": {\n \"your_order_id\": \"ORD-8812\"\n },\n \"to_number\": \"+15555550100\",\n \"variables\": {\n \"appointment_date\": \"2026-09-15\",\n \"patient_name\": \"Jane Doe\"\n }\n}"
response = http.request(request)
puts response.read_body{
"agent_id": "3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f",
"call_id": "9d2f7a3c-8e4b-4f1d-a6c7-2b3c4d5e6f70",
"created_at": "2026-09-10T14:03:11.412Z",
"from_number": "+15555550199",
"status": "queued",
"to_number": "+15555550100"
}{
"detail": {
"error": "Agent is not active.",
"error_code": "agent_inactive"
}
}{
"detail": "Invalid or expired API key"
}{
"detail": {
"error": "Agent not found.",
"error_code": "agent_not_found"
}
}{
"detail": {
"error": "Required variables are missing: patient_dob",
"error_code": "missing_variables",
"missing_variables": [
"patient_dob"
]
}
}{
"detail": {
"call_id": "9d2f7a3c-8e4b-4f1d-a6c7-2b3c4d5e6f70",
"error": "Could not dispatch the call.",
"error_code": "dispatch_error"
}
}Create an outbound call
Place an outbound call with one of your agents.
Returns as soon as the call is queued; it does not wait for the call to be
answered. call.started, call.ended and call.analyzed webhooks follow
if you have an endpoint subscribed, and GET /v1/calls/{call_id} returns
the current state at any time.
Retell-compatible field names are accepted as aliases: override_agent_id
→ agent_id, retell_llm_dynamic_variables → variables.
override_agent_version and any unknown fields are ignored, so a client
written for Retell’s create-call endpoint works with only a URL change.
curl --request POST \
--url https://api.contourvoice.com/v1/calls \
--header 'Authorization: Bearer <token>' \
--header 'Content-Type: application/json' \
--data '
{
"agent_id": "3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f",
"from_number": "+15555550199",
"metadata": {
"your_order_id": "ORD-8812"
},
"to_number": "+15555550100",
"variables": {
"appointment_date": "2026-09-15",
"patient_name": "Jane Doe"
}
}
'import requests
url = "https://api.contourvoice.com/v1/calls"
payload = {
"agent_id": "3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f",
"from_number": "+15555550199",
"metadata": { "your_order_id": "ORD-8812" },
"to_number": "+15555550100",
"variables": {
"appointment_date": "2026-09-15",
"patient_name": "Jane Doe"
}
}
headers = {
"Authorization": "Bearer <token>",
"Content-Type": "application/json"
}
response = requests.post(url, json=payload, headers=headers)
print(response.text)const options = {
method: 'POST',
headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
body: JSON.stringify({
agent_id: '3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f',
from_number: '+15555550199',
metadata: {your_order_id: 'ORD-8812'},
to_number: '+15555550100',
variables: {appointment_date: '2026-09-15', patient_name: 'Jane Doe'}
})
};
fetch('https://api.contourvoice.com/v1/calls', 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.contourvoice.com/v1/calls",
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([
'agent_id' => '3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f',
'from_number' => '+15555550199',
'metadata' => [
'your_order_id' => 'ORD-8812'
],
'to_number' => '+15555550100',
'variables' => [
'appointment_date' => '2026-09-15',
'patient_name' => 'Jane Doe'
]
]),
CURLOPT_HTTPHEADER => [
"Authorization: Bearer <token>",
"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.contourvoice.com/v1/calls"
payload := strings.NewReader("{\n \"agent_id\": \"3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f\",\n \"from_number\": \"+15555550199\",\n \"metadata\": {\n \"your_order_id\": \"ORD-8812\"\n },\n \"to_number\": \"+15555550100\",\n \"variables\": {\n \"appointment_date\": \"2026-09-15\",\n \"patient_name\": \"Jane Doe\"\n }\n}")
req, _ := http.NewRequest("POST", url, payload)
req.Header.Add("Authorization", "Bearer <token>")
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://api.contourvoice.com/v1/calls")
.header("Authorization", "Bearer <token>")
.header("Content-Type", "application/json")
.body("{\n \"agent_id\": \"3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f\",\n \"from_number\": \"+15555550199\",\n \"metadata\": {\n \"your_order_id\": \"ORD-8812\"\n },\n \"to_number\": \"+15555550100\",\n \"variables\": {\n \"appointment_date\": \"2026-09-15\",\n \"patient_name\": \"Jane Doe\"\n }\n}")
.asString();require 'uri'
require 'net/http'
url = URI("https://api.contourvoice.com/v1/calls")
http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n \"agent_id\": \"3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f\",\n \"from_number\": \"+15555550199\",\n \"metadata\": {\n \"your_order_id\": \"ORD-8812\"\n },\n \"to_number\": \"+15555550100\",\n \"variables\": {\n \"appointment_date\": \"2026-09-15\",\n \"patient_name\": \"Jane Doe\"\n }\n}"
response = http.request(request)
puts response.read_body{
"agent_id": "3f1c1b2e-6d1a-4c0e-9b2f-1a2b3c4d5e6f",
"call_id": "9d2f7a3c-8e4b-4f1d-a6c7-2b3c4d5e6f70",
"created_at": "2026-09-10T14:03:11.412Z",
"from_number": "+15555550199",
"status": "queued",
"to_number": "+15555550100"
}{
"detail": {
"error": "Agent is not active.",
"error_code": "agent_inactive"
}
}{
"detail": "Invalid or expired API key"
}{
"detail": {
"error": "Agent not found.",
"error_code": "agent_not_found"
}
}{
"detail": {
"error": "Required variables are missing: patient_dob",
"error_code": "missing_variables",
"missing_variables": [
"patient_dob"
]
}
}{
"detail": {
"call_id": "9d2f7a3c-8e4b-4f1d-a6c7-2b3c4d5e6f70",
"error": "Could not dispatch the call.",
"error_code": "dispatch_error"
}
}Authorizations
Your organization's API key (sk_cont_...), sent as Authorization: Bearer sk_cont_.... Keep it server-side.
Body
The agent to place the call with. Contour gives you this id. Retell alias: override_agent_id.
Number to dial. E.164 (+1...) preferred.
Caller ID. Optional; if sent it must equal the agent's configured outbound number or the request is rejected with from_number_mismatch.
Any JSON object. Stored untouched and echoed back on every webhook and on GET /v1/calls/{call_id}.
Per-call values the agent's script uses. Some are required per agent; a missing one is a 422 listing the keys. Retell alias: retell_llm_dynamic_variables.
Response
Successful Response
The agent placing the call.
Stable for the life of the call: the same id on every webhook and on GET /v1/calls/{call_id}.
When the call was accepted.
Always queued on creation.
The number being dialed.
The caller ID the call is placed from.