Nixflex - AI Voice Platform for Building AI Phone Agents

Update phone number

curl --request PATCH \
  --url https://api.nixflex.com/v1/phone-numbers/{phone_number}

const options = {method: 'PATCH'};

fetch('https://api.nixflex.com/v1/phone-numbers/{phone_number}', 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.nixflex.com/v1/phone-numbers/{phone_number}",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "PATCH",
]);

$response = curl_exec($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/phone-numbers/{phone_number}"

	req, _ := http.NewRequest("PATCH", 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/phone-numbers/{phone_number}")

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

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

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

PATCH

phone-numbers

{phone_number}

Update phone number

curl --request PATCH \
  --url https://api.nixflex.com/v1/phone-numbers/{phone_number}

const options = {method: 'PATCH'};

fetch('https://api.nixflex.com/v1/phone-numbers/{phone_number}', 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.nixflex.com/v1/phone-numbers/{phone_number}",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "PATCH",
]);

$response = curl_exec($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/phone-numbers/{phone_number}"

	req, _ := http.NewRequest("PATCH", 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/phone-numbers/{phone_number}")

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

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

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

Update the per-number settings on a number you have already imported: the call business profile, the voice, and the SMS and web agent instructions. Every field is optional - send only what you want to change. Any field left out is untouched. Each channel is independent:

custom_prompt shapes phone calls (layered on top of the agent prompt).
sms_prompt is the SMS agent (SMS agent) - it does not affect calls.
web_prompt is the web agent (Web agent) - it does not affect calls or SMS.
sms_reply_enabled turns SMS auto-reply on or off for the number.
speaking_rate sets how fast this number talks, overriding the agent’s speed.
dtmf_enabled lets callers type digits on their keypad instead of saying them.
record_call controls whether calls on this number are recorded.

Request

curl -X PATCH https://api.nixflex.com/v1/phone-numbers/+447446466847 \
  -H "Authorization: Bearer KEY_ID:KEY_SECRET" \
  -H "Content-Type: application/json" \
  -d '{
    "sms_reply_enabled": true,
    "sms_prompt": "You are the text assistant for Smile Dental. Open Mon-Fri 9am-5pm. A check-up is 45 pounds. You can book, reschedule and cancel. Keep replies short."
  }'

URL-encode the + if your HTTP client doesn’t do it automatically: %2B447446466847.

Body parameters

Field	Type	Required	Notes
`custom_prompt`	string or null	No	The business profile layered on top of the agent prompt on phone calls. Maximum 8000 characters. Send `null` or an empty string to clear it - the number then falls back to the agent prompt alone. Does not affect SMS or web chat.
`voice_id`	string or null	No	The voice this number speaks with on calls, overriding the agent’s voice (e.g. `Craig`, `Eleanor`, `Ashley`). Send `null` or empty to fall back to the agent’s voice. Must be an exact, valid voice ID.
`sms_reply_enabled`	boolean	No	Turns the SMS agent (auto-reply) on or off for this number. `false` by default - a number only replies to texts when you turn this on. Accepts `true`/`false`.
`sms_prompt`	string or null	No	Instructions for the SMS agent on this number. Independent of `custom_prompt`. Maximum 20000 characters. Send `null` or an empty string to clear it.
`web_prompt`	string or null	No	Instructions for the Web agent on this number. Independent of `custom_prompt` and `sms_prompt`. Maximum 20000 characters. Send `null` or an empty string to clear it.
`speaking_rate`	number or null	No	How fast this number speaks on calls, overriding the agent’s speed. `1.0` is normal, `0.5` is half speed, `1.5` is half again as fast. A value outside that range is clamped to the nearest limit rather than rejected. `null` means not set - the number inherits the agent’s speed, so a `null` number under a `1.5` agent still speaks at `1.5`. To make one number normal while the agent stays fast, send `1`, not `null`. See Voices.
`dtmf_enabled`	boolean or null	No	Whether callers on this number can type digits on their phone keypad instead of speaking them. `null` means not set, so the number inherits the agent’s setting - a `null` number under an agent with keypad input on still accepts keypad entry. Send `false` to switch one number off while the agent stays on. See Keypad input.
`record_call`	boolean or null	No	Whether calls on this number are recorded. Recording is on unless switched off. `null` means not set, so the number inherits the agent’s setting. Send `false` to stop recording one number while the agent keeps recording. The transcript is unaffected either way, and `recording_url` on the call record becomes `null`. See Call recording.

Send at least one field. An empty body is rejected.

Response

200 OK returns the updated number:

{
  "phone_number": {
    "phone_number": "+447446466847",
    "agent_id": "agent_125207e452f8714a",
    "custom_prompt": "Business: Smile Dental Croydon...",
    "voice_id": "Craig",
    "sms_reply_enabled": true,
    "sms_prompt": "You are the text assistant for Smile Dental...",
    "web_prompt": null,
    "speaking_rate": 0.9,
    "dtmf_enabled": null,
    "record_call": false
  }
}

Takes effect on the very next call or text - no deploy, no re-import.

Errors

Code	HTTP	Cause
`missing_field`	400	Empty body - no updatable field present (send `null` to clear a field, not an empty body)
`custom_prompt_too_long`	400	`custom_prompt` over 8000 characters
`sms_prompt_too_long`	400	`sms_prompt` over 20000 characters
`web_prompt_too_long`	400	`web_prompt` over 20000 characters
`number_not_found`	404	Number doesn’t exist OR belongs to a different account

Use case: reseller end-customer onboarding

One agent template, many end-customers - each number carries its own call profile, SMS agent, and web agent:

// Customer edits their business details in YOUR app -> you sync to Nixflex
await fetch(
  `https://api.nixflex.com/v1/phone-numbers/${clinicNumber}`,
  {
    method: 'PATCH',
    headers: {
      'Authorization': `Bearer ${NIXFLEX_KEY_ID}:${NIXFLEX_KEY_SECRET}`,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      custom_prompt: `Business: ${clinic.name}. Address: ${clinic.address}. Open ${clinic.hours}. ${clinic.services}`,
      voice_id: clinic.voice_id,
      sms_reply_enabled: true,
      sms_prompt: `You are the text assistant for ${clinic.name}. ${clinic.details}. You can book, reschedule and cancel. Keep replies short.`,
      web_prompt: `You are the online assistant for ${clinic.name}. ${clinic.details}. If someone wants to book, tell them to call.`,
      speaking_rate: clinic.speaking_rate
    })
  }
);

The changes take effect on the next call or text. This is how a 200-location rollout stays one agent + one PATCH per location - across calls, SMS, and web.

SMS agent - the sms_prompt + sms_reply_enabled feature
Web agent - the web_prompt feature
Import phone number
Voices - the voice_id and speaking_rate settings
Keypad input - the dtmf_enabled setting
Call recording - the record_call setting

API

Platform API

Update phone number

Request

Body parameters

Response

Errors

Use case: reseller end-customer onboarding

​Request

​Body parameters

​Response

​Errors

​Use case: reseller end-customer onboarding

​Related

Request

Body parameters

Response

Errors

Use case: reseller end-customer onboarding

Related