Nixflex - AI Voice Platform for Building AI Phone Agents

Create SMS campaign

curl --request POST \
  --url https://api.nixflex.com/v1/sms/campaigns

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.nixflex.com/v1/sms/campaigns",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
]);

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

curl_close($curl);

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

package main

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

func main() {

	url := "https://api.nixflex.com/v1/sms/campaigns"

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

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

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

	fmt.Println(string(body))

}

require 'uri'
require 'net/http'

url = URI("https://api.nixflex.com/v1/sms/campaigns")

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

request = Net::HTTP::Post.new(url)

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

POST

sms

campaigns

Create SMS campaign

curl --request POST \
  --url https://api.nixflex.com/v1/sms/campaigns

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.nixflex.com/v1/sms/campaigns",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
]);

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

curl_close($curl);

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

package main

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

func main() {

	url := "https://api.nixflex.com/v1/sms/campaigns"

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

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

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

	fmt.Println(string(body))

}

require 'uri'
require 'net/http'

url = URI("https://api.nixflex.com/v1/sms/campaigns")

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

request = Net::HTTP::Post.new(url)

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

Creates an SMS campaign. Optionally launches it immediately.

Campaigns are one-time broadcasts. Replies are handled by the agent using its system_prompt — include any campaign context in the agent’s prompt before launching.

Request

curl -X POST https://api.nixflex.com/v1/sms/campaigns \
  -H "Authorization: Bearer KEY_ID:KEY_SECRET" \
  -H "Content-Type: application/json" \
  -d '{
    "agent_id": "agent_125207e452f8714a",
    "from_number": "+447446466847",
    "name": "March promotion",
    "message_template": "Hi {{first_name}}, 20% off cleanings this month at Acme Dental. Reply YES to book.",
    "recipients": [
      { "phone": "+447111000001", "variables": { "first_name": "Sarah" } },
      { "phone": "+447111000002", "variables": { "first_name": "James" } }
    ],
    "schedule_type": "now"
  }'

Body parameters

Field	Type	Required	Notes
`agent_id`	string	Yes	Agent associated with the campaign
`from_number`	string	Yes	Your imported Twilio number. SMS campaigns do not support Telnyx numbers yet - the request is rejected at create. Single sends via POST /v1/sms work on both.
`name`	string	Yes	Display name in dashboard
`message_template`	string	Yes	Message text. Supports `{{variable}}` placeholders
`recipients`	array	Yes	Up to 10,000. Each item: `{ phone, variables }`
`schedule_type`	enum	Yes	`now` or `schedule`
`scheduled_at`	ISO date	If `schedule`	When to launch

Recipient object

Field	Type	Required	Notes
`phone`	string	Yes	E.164 format, e.g. `+447111000001`
`variables`	object	No	Key-value pairs to fill `{{placeholders}}` in the template

Placeholders

Use {{variable_name}} in message_template. Each recipient’s variables object fills them. Template: Hi {{first_name}}, see you on {{day}}. Recipient: { "phone": "+44...", "variables": { "first_name": "Sarah", "day": "Tuesday" } } Sent SMS: Hi Sarah, see you on Tuesday. Missing variables render as empty strings (no crash).

Response

201 Created:

{
  "campaign_id": "smsc_a1b2c3d4",
  "agent_id": "agent_125207e452f8714a",
  "name": "March promotion",
  "status": "running",
  "total_count": 2,
  "delivered_count": 0,
  "failed_count": 0,
  "pending_count": 2,
  "source": "api",
  "created_at": "2026-05-17T03:45:12Z"
}

When schedule_type is now, returns status: running and sends immediately. With schedule, returns status: scheduled — launch later with Launch SMS campaign.

Errors

See Errors. Common: agent_not_owned, from_number_not_owned, too_many_recipients, invalid_schedule.

API

Platform API

Create SMS campaign

Request

Body parameters

Recipient object

Placeholders

Response

Errors

​Request

​Body parameters

​Recipient object

​Placeholders

​Response

​Errors

Request

Body parameters

Recipient object

Placeholders

Response

Errors