10DLC Phone Number Assignment

After your brand is registered and campaign is approved, you need to assign phone numbers to the campaign before sending messages. Only numbers assigned to an active campaign can send 10DLC A2P messages.

How it works

Requirement	Details
Number type	US long code (10-digit) numbers only
Messaging profile	Number must be assigned to a messaging profile first
Campaign status	Campaign must be `ACTIVE` (approved by carriers)
One campaign per number	Each number can only be assigned to one campaign at a time

Numbers not assigned to an active 10DLC campaign will have messages filtered or blocked by carriers on AT&T, T-Mobile, and other major US networks.

Assign a number to a campaign

API
Portal

curl -X POST https://api.telnyx.com/v2/10dlc/phoneNumberCampaign \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "phoneNumber": "+15551234567",
    "campaignId": "CAMPAIGN_ID"
  }'

import os
import requests

API_KEY = os.environ.get("TELNYX_API_KEY")
headers = {
    "Authorization": f"Bearer {API_KEY}",
    "Content-Type": "application/json",
}

response = requests.post(
    "https://api.telnyx.com/v2/10dlc/phoneNumberCampaign",
    headers=headers,
    json={
        "phoneNumber": "+15551234567",
        "campaignId": "CAMPAIGN_ID",
    },
)
result = response.json()
print(f"Number: {result['data']['phoneNumber']}")
print(f"Status: {result['data']['status']}")

const axios = require('axios');

const headers = {
  Authorization: `Bearer ${process.env.TELNYX_API_KEY}`,
  'Content-Type': 'application/json',
};

const response = await axios.post(
  'https://api.telnyx.com/v2/10dlc/phoneNumberCampaign',
  {
    phoneNumber: '+15551234567',
    campaignId: 'CAMPAIGN_ID',
  },
  { headers }
);

console.log(`Number: ${response.data.data.phoneNumber}`);
console.log(`Status: ${response.data.data.status}`);

require "net/http"
require "json"
require "uri"

uri = URI("https://api.telnyx.com/v2/10dlc/phoneNumberCampaign")
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true

request = Net::HTTP::Post.new(uri)
request["Authorization"] = "Bearer #{ENV['TELNYX_API_KEY']}"
request["Content-Type"] = "application/json"
request.body = {
  phoneNumber: "+15551234567",
  campaignId: "CAMPAIGN_ID"
}.to_json

response = http.request(request)
result = JSON.parse(response.body)
puts "Number: #{result['data']['phoneNumber']}"
puts "Status: #{result['data']['status']}"

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"net/http"
	"os"
)

func main() {
	data := map[string]string{
		"phoneNumber": "+15551234567",
		"campaignId":  "CAMPAIGN_ID",
	}

	body, _ := json.Marshal(data)
	req, _ := http.NewRequest("POST", "https://api.telnyx.com/v2/10dlc/phoneNumberCampaign", bytes.NewBuffer(body))
	req.Header.Set("Authorization", "Bearer "+os.Getenv("TELNYX_API_KEY"))
	req.Header.Set("Content-Type", "application/json")

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer resp.Body.Close()

	var result map[string]interface{}
	json.NewDecoder(resp.Body).Decode(&result)
	d := result["data"].(map[string]interface{})
	fmt.Printf("Number: %s\nStatus: %s\n", d["phoneNumber"], d["status"])
}

<?php
$apiKey = getenv('TELNYX_API_KEY');

$data = [
    'phoneNumber' => '+15551234567',
    'campaignId' => 'CAMPAIGN_ID',
];

$ch = curl_init('https://api.telnyx.com/v2/10dlc/phoneNumberCampaign');
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        "Authorization: Bearer {$apiKey}",
        'Content-Type: application/json',
    ],
    CURLOPT_POSTFIELDS => json_encode($data),
]);

$response = json_decode(curl_exec($ch), true);
curl_close($ch);

echo "Number: {$response['data']['phoneNumber']}\n";
echo "Status: {$response['data']['status']}\n";

using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;

var apiKey = Environment.GetEnvironmentVariable("TELNYX_API_KEY");
var client = new HttpClient();
client.DefaultRequestHeaders.Authorization =
    new AuthenticationHeaderValue("Bearer", apiKey);

var data = new { phoneNumber = "+15551234567", campaignId = "CAMPAIGN_ID" };
var json = JsonSerializer.Serialize(data);
var content = new StringContent(json, Encoding.UTF8, "application/json");

var response = await client.PostAsync(
    "https://api.telnyx.com/v2/10dlc/phoneNumberCampaign", content);
var result = await response.Content.ReadAsStringAsync();

using var doc = JsonDocument.Parse(result);
var d = doc.RootElement.GetProperty("data");
Console.WriteLine($"Number: {d.GetProperty("phoneNumber")}");
Console.WriteLine($"Status: {d.GetProperty("status")}");

Bulk assignment

When assigning multiple numbers to the same campaign, loop through your numbers programmatically:

import os
import requests
import time

API_KEY = os.environ.get("TELNYX_API_KEY")
headers = {
    "Authorization": f"Bearer {API_KEY}",
    "Content-Type": "application/json",
}

campaign_id = "CAMPAIGN_ID"
phone_numbers = [
    "+15551234567",
    "+15551234568",
    "+15551234569",
    "+15551234570",
    "+15551234571",
]

results = {"success": [], "failed": []}

for number in phone_numbers:
    try:
        response = requests.post(
            "https://api.telnyx.com/v2/10dlc/phoneNumberCampaign",
            headers=headers,
            json={"phoneNumber": number, "campaignId": campaign_id},
        )
        if response.status_code in (200, 201):
            results["success"].append(number)
            print(f"✓ {number} assigned")
        else:
            error = response.json().get("errors", [{}])[0].get("detail", "Unknown")
            results["failed"].append({"number": number, "error": error})
            print(f"✗ {number}: {error}")
    except Exception as e:
        results["failed"].append({"number": number, "error": str(e)})
    time.sleep(0.5)  # Rate limit safety

print(f"\nAssigned: {len(results['success'])}, Failed: {len(results['failed'])}")

const axios = require('axios');

const headers = {
  Authorization: `Bearer ${process.env.TELNYX_API_KEY}`,
  'Content-Type': 'application/json',
};

const campaignId = 'CAMPAIGN_ID';
const phoneNumbers = [
  '+15551234567',
  '+15551234568',
  '+15551234569',
  '+15551234570',
  '+15551234571',
];

const results = { success: [], failed: [] };

for (const number of phoneNumbers) {
  try {
    await axios.post(
      'https://api.telnyx.com/v2/10dlc/phoneNumberCampaign',
      { phoneNumber: number, campaignId },
      { headers }
    );
    results.success.push(number);
    console.log(`✓ ${number} assigned`);
  } catch (err) {
    const detail = err.response?.data?.errors?.[0]?.detail || err.message;
    results.failed.push({ number, error: detail });
    console.log(`✗ ${number}: ${detail}`);
  }
  await new Promise((r) => setTimeout(r, 500)); // Rate limit safety
}

console.log(`\nAssigned: ${results.success.length}, Failed: ${results.failed.length}`);

#!/bin/bash
# Bulk assign numbers to a campaign
CAMPAIGN_ID="CAMPAIGN_ID"
NUMBERS=("+15551234567" "+15551234568" "+15551234569")

for NUM in "${NUMBERS[@]}"; do
  RESULT=$(curl -s -w "\n%{http_code}" -X POST \
    https://api.telnyx.com/v2/10dlc/phoneNumberCampaign \
    -H "Content-Type: application/json" \
    -H "Authorization: Bearer $TELNYX_API_KEY" \
    -d "{\"phoneNumber\": \"$NUM\", \"campaignId\": \"$CAMPAIGN_ID\"}")

  HTTP_CODE=$(echo "$RESULT" | tail -1)
  if [ "$HTTP_CODE" = "200" ] || [ "$HTTP_CODE" = "201" ]; then
    echo "✓ $NUM assigned"
  else
    echo "✗ $NUM failed (HTTP $HTTP_CODE)"
  fi
  sleep 0.5
done

Number pool integration

If you’re using Number Pools, numbers in the pool must also be assigned to a 10DLC campaign. The number pool distributes sending across multiple numbers, but each number still needs campaign registration.

Create your campaign

Enable number pool on messaging profile

Configure your messaging profile with number pool enabled.

Assign all pool numbers to the campaign

Every number in the pool must be assigned to the same campaign. Use the bulk assignment method above.

Verify assignments

List all numbers assigned to your campaign to confirm all pool numbers are included.

If a number in your pool is not assigned to a campaign, messages sent from that number will be filtered by carriers. This creates inconsistent delivery — some messages succeed, others fail depending on which pool number is selected.

List assigned numbers

# List all numbers assigned to a campaign
curl -s "https://api.telnyx.com/v2/10dlc/phoneNumberCampaign?filter[campaignId]=CAMPAIGN_ID" \
  -H "Authorization: Bearer YOUR_API_KEY" | jq '.data[] | {phoneNumber, status}'

response = requests.get(
    "https://api.telnyx.com/v2/10dlc/phoneNumberCampaign",
    headers=headers,
    params={"filter[campaignId]": campaign_id},
)
numbers = response.json()["data"]
for n in numbers:
    print(f"{n['phoneNumber']} | {n['status']}")

const response = await axios.get(
  'https://api.telnyx.com/v2/10dlc/phoneNumberCampaign',
  {
    headers,
    params: { 'filter[campaignId]': campaignId },
  }
);

response.data.data.forEach((n) => {
  console.log(`${n.phoneNumber} | ${n.status}`);
});

Remove a number from a campaign

curl -X DELETE "https://api.telnyx.com/v2/10dlc/phoneNumberCampaign/+15551234567" \
  -H "Authorization: Bearer YOUR_API_KEY"

response = requests.delete(
    "https://api.telnyx.com/v2/10dlc/phoneNumberCampaign/+15551234567",
    headers=headers,
)
print(f"Status: {response.status_code}")  # 200 = success

await axios.delete(
  'https://api.telnyx.com/v2/10dlc/phoneNumberCampaign/+15551234567',
  { headers }
);
console.log('Number removed from campaign');

Removing a number from a campaign means it can no longer send 10DLC messages. You can reassign it to a different campaign afterward.

Troubleshooting

Error: Number not found

Cause: The phone number isn’t on your Telnyx account or isn’t in E.164 format.Fix:

Verify the number is in your account: GET /v2/phone_numbers?filter[phone_number]=+15551234567
Ensure E.164 format: +1 followed by 10 digits (e.g., +15551234567)

Error: Number not assigned to a messaging profile

Cause: Numbers must be assigned to a messaging profile before campaign assignment.Fix:

# Assign number to a messaging profile first
curl -X PATCH https://api.telnyx.com/v2/phone_numbers/+15551234567 \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"messaging_profile_id": "PROFILE_ID"}'

Error: Campaign not active

Cause: The campaign hasn’t been approved by carriers yet.Fix:

Check campaign status: GET /v2/10dlc/campaignBuilder/{campaignId}
Wait for carrier approval (1-5 business days)
Set up Event Notifications to get notified when the campaign is approved

Error: Number already assigned to another campaign

Cause: Each number can only be assigned to one campaign at a time.Fix:

Remove the number from the current campaign: DELETE /v2/10dlc/phoneNumberCampaign/+15551234567
Assign it to the new campaign

Messages still being filtered after assignment

Cause: Carrier provisioning takes time after assignment.Fix:

Wait 24-72 hours for all carriers to propagate
Check MNO metadata on the campaign for per-carrier status
Verify the number is sending the same type of content registered in the campaign
Check Message Detail Records for specific error codes

Bulk assignment partially failing

Cause: Some numbers may have issues while others succeed.Fix:

Check each error response for the specific reason
Common issues: number on different account, already assigned, not on messaging profile
Use the bulk assignment script above with error tracking to identify which numbers failed and why

Sending Messages

Messaging Profiles

Short Code

Hosted Numbers

Opt Outs

Phone Numbers

Toll Free Verification

10 DLC

For AI Agents

10DLC Phone Number Assignment

How it works

Assign a number to a campaign

Bulk assignment

Number pool integration

List assigned numbers

Remove a number from a campaign

Troubleshooting

Next steps

Campaign Registration

Number Pool

10DLC Rate Limits

Send Your First Message

​How it works

​Assign a number to a campaign

​Bulk assignment

​Number pool integration

​List assigned numbers

​Remove a number from a campaign

​Troubleshooting

​Next steps

Campaign Registration

Number Pool

10DLC Rate Limits

Send Your First Message

How it works

Assign a number to a campaign

Bulk assignment

Number pool integration

List assigned numbers

Remove a number from a campaign

Troubleshooting

Next steps