Twilio Lookup API

Stronger security. No user experience tradeoff. Build with Lookup API.

Lookup API uses mobile-based signals to provide smooth and robust protection for digital platforms and users, minimizing fraudulent activities without compromising the experience.

Start for free View pricing

Illustration showing how a business can use Lookup to verify a customer’s phone number as a security measure.

How Twilio Lookup API works

Interface showing user phone numbers with authentication status as valid or invalid.

Twilio Lookup API uses mobile-identity signals to verify users and prevent fraud.

It works in the background to look up a phone number and identify real users from those with suspicious behaviors and characteristics, so you can apply additional friction to only the users who present a risk.

With one API, you can look up a number of attributes to prevent potential fraud and undelivered messages.

Explore docs

Get dialed in to fraud signals with phone number lookup

Improve user security, delivery, and conversions in one fell swoop with a single builder-friendly API.

Increase SMS message and voice deliverability

Improve contact rates by using mobile-based signals that give accurate contact information such as formatting, line type, line status, and active consent. When you can communicate more effectively with end users, you can also lower delivery costs.

Resy securely verifies customers and delivers verification codes to confirm their identities, keep their accounts secure, and maintain on-time message delivery.

35 million

registered users

21 million

messages sent monthly

Read Resy’s story

Fraud prevention across the customer journey

Prevent fraudulent schemes like fake account creation, bot attacks, SIM swap, promo abuse, SMS Pumping fraud, and other types of fraud from damaging your platform at key touchpoints of the customer journey.

Learn about fraud prevention

Tradier increased the number of user verification sources it uses while also improving its user experience. By filtering out real unique users with Lookup Identity Match and flagging suspicious ones, Tradier reduced validation times by around 90%.

Read Tradier’s story

Enrich data and risk models with mobile signals

Include key data such as risk scoring and phone number attributes in fraud risk models. This enriches the user information you have in your fraud data pipeline to identify fraudsters and assess user risk.

After an estimated $300,000 in losses from artificially inflated SMS traffic over the course of three years, Persona needed better tools to prevent SMS pumping fraud by identifying fraud behavior.

6 months

without SMS pumping traffic spikes

$300,000

estimated fraud losses before Lookup

Read Persona’s story

Raise conversion rates and boost revenue

Leverage authoritative data and mobile based signals to fast track time to conversion and boost revenue.

Choco uses the Lookup API to validate phone numbers when processing orders from restaurants and food service operators with suppliers. This allows them to complete orders securely, easily, and efficiently.

hours a week saved with ordering

10,000+

suppliers in Choco’s ecosystem

Read Choco’s story

Lookup API features

A complete toolset to protect against fraud with phone number intelligence data, streamline and personalize onboarding, and confirm phone number legitimacy to protect your sender reputation.

Example of query parameters including FirstName, AddressLine, City, and State with a phone number

Popular

Line Type Intelligence

Identify the carrier and phone line type from mobile, landline, fixed VoIP, non-fixed VoIP, toll free, and more to mitigate fake accounts, scrub contact lists, and improve deliverability.

Learn about Line Type Intelligence

Formatting and validation

Validate and reformat phone numbers automatically to match national and global dialing standards for optimal deliverability.
Identity Match

Prevent bots and false account creation. Confirm user identities by matching user-supplied data using a specified phone number against authoritative sources.
Call forwarding

Expose at-risk numbers with real-time access to the call forwarding status for mobile numbers. Only available in the UK.
Reassigned number

Check if a phone number has been reassigned since the user's last consent date. Increase user conversion and avoid legal breach by reaching out to the right person.

SMS Pumping Risk Score

Powered by advanced machine learning models, SMS Pumping Risk Score can effectively identify and flag malicious behavior associated with phone numbers involved in SMS Pumping Fraud.
Line status

Check if a phone number is active or reachable on its carrier network. Optimize cost and delivery by only sending messages to active contacts.
Caller name

Identify inbound callers then personalize outreach using the verified caller or business name to improve conversions, security, and customer experience. Only available in the US.
SIM swap

Detect SIM swap to stop fraud and account takeovers with timestamps and dates of any SIM changes, plus configurable risk tolerance that enables accurate modeling and metrics.

Get started with Twilio Lookup

With a few lines of code, you can start to programmatically get information about phone numbers and who you’re messaging. Reduce undeliverable messages, identify local-friendly number formats, and resolve caller names.

Create a message

      

			// Download the helper library from https://www.twilio.com/docs/node/install
// Find your Account SID and Auth Token at twilio.com/console
// and set the environment variables. See http://twil.io/secure
const accountSid = process.env.TWILIO_ACCOUNT_SID;
const authToken = process.env.TWILIO_AUTH_TOKEN;
const client = require('twilio')(accountSid, authToken);

client.verify.v2.services('VAXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX')
                .verifications
                .create({to: '+15017122661', channel: 'sms'})
                .then(verification => console.log(verification.sid));
		


      

			# Download the helper library from https://www.twilio.com/docs/python/install
import os
from twilio.rest import Client


# Find your Account SID and Auth Token at twilio.com/console
# and set the environment variables. See http://twil.io/secure
account_sid = os.environ['TWILIO_ACCOUNT_SID']
auth_token = os.environ['TWILIO_AUTH_TOKEN']
client = Client(account_sid, auth_token)

verification = client.verify \
                     .v2 \
                     .services('VAXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX') \
                     .verifications \
                     .create(to='+15017122661', channel='sms')

print(verification.sid)
		


      

			// Install the C# / .NET helper library from twilio.com/docs/csharp/install

using System;
using Twilio;
using Twilio.Rest.Verify.V2.Service;


class Program
{
    static void Main(string[] args)
    {
        // Find your Account SID and Auth Token at twilio.com/console
        // and set the environment variables. See http://twil.io/secure
        string accountSid = Environment.GetEnvironmentVariable("TWILIO_ACCOUNT_SID");
        string authToken = Environment.GetEnvironmentVariable("TWILIO_AUTH_TOKEN");

        TwilioClient.Init(accountSid, authToken);

        var verification = VerificationResource.Create(
            to: "+15017122661",
            channel: "sms",
            pathServiceSid: "VAXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
        );

        Console.WriteLine(verification.Sid);
    }
}
		


      

			// Install the Java helper library from twilio.com/docs/java/install

import com.twilio.Twilio;
import com.twilio.rest.verify.v2.service.Verification;

public class Example {
    // Find your Account SID and Auth Token at twilio.com/console
    // and set the environment variables. See http://twil.io/secure
    public static final String ACCOUNT_SID = System.getenv("TWILIO_ACCOUNT_SID");
    public static final String AUTH_TOKEN = System.getenv("TWILIO_AUTH_TOKEN");

    public static void main(String[] args) {
        Twilio.init(ACCOUNT_SID, AUTH_TOKEN);
        Verification verification = Verification.creator(
                "VAXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX",
                "+15017122661",
                "sms")
            .create();

        System.out.println(verification.getSid());
    }
		


      

			$verification = $twilio->verify->v2->services("VAXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX")
                                   ->verifications
                                   ->create("+15017122661", "sms");

print($verification->sid);
		


      

			# Download the helper library from https://www.twilio.com/docs/ruby/install
require 'rubygems'
require 'twilio-ruby'

# Find your Account SID and Auth Token at twilio.com/console
# and set the environment variables. See http://twil.io/secure
account_sid = ENV['TWILIO_ACCOUNT_SID']
auth_token = ENV['TWILIO_AUTH_TOKEN']
@client = Twilio::REST::Client.new(account_sid, auth_token)

verification = @client.verify
                      .v2
                      .services('VAXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX')
                      .verifications
                      .create(to: '+15017122661', channel: 'sms')

puts verification.sid
		


      

			# Download the helper library from https://www.twilio.com/docs/ruby/install
require 'rubygems'
require 'twilio-ruby'

# Find your Account SID and Auth Token at twilio.com/console
# and set the environment variables. See http://twil.io/secure
account_sid = ENV['TWILIO_ACCOUNT_SID']
auth_token = ENV['TWILIO_AUTH_TOKEN']
@client = Twilio::REST::Client.new(account_sid, auth_token)

verification = @client.verify
                      .v2
                      .services('VAXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX')
                      .verifications
                      .create(to: '+15017122661', channel: 'sms')

puts verification.sid
# Download the helper library from https://www.twilio.com/docs/python/install
import os
from twilio.rest import Client


# Find your Account SID and Auth Token at twilio.com/console
# and set the environment variables. See http://twil.io/secure
account_sid = os.environ['TWILIO_ACCOUNT_SID']
auth_token = os.environ['TWILIO_AUTH_TOKEN']
client = Client(account_sid, auth_token)

verification = client.verify \
                     .v2 \
                     .services('VAXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX') \
                     .verifications \
                     .create(to='+15017122661', channel='sms')

print(verification.sid)
<?php

// Update the path below to your autoload.php,
// see https://getcomposer.org/doc/01-basic-usage.md
require_once '/path/to/vendor/autoload.php';

use Twilio\Rest\Client;

// Find your Account SID and Auth Token at twilio.com/console
// and set the environment variables. See http://twil.io/secure
$sid = getenv("TWILIO_ACCOUNT_SID");
$token = getenv("TWILIO_AUTH_TOKEN");
$twilio = new Client($sid, $token);

$verification = $twilio->verify->v2->services("VAXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX")
                                   ->verifications
                                   ->create("+15017122661", "sms");

print($verification->sid);
// Download the helper library from https://www.twilio.com/docs/node/install
// Find your Account SID and Auth Token at twilio.com/console
// and set the environment variables. See http://twil.io/secure
const accountSid = process.env.TWILIO_ACCOUNT_SID;
const authToken = process.env.TWILIO_AUTH_TOKEN;
const client = require('twilio')(accountSid, authToken);

client.verify.v2.services('VAXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX')
                .verifications
                .create({to: '+15017122661', channel: 'sms'})
                .then(verification => console.log(verification.sid));
// Install the Java helper library from twilio.com/docs/java/install

import com.twilio.Twilio;
import com.twilio.rest.verify.v2.service.Verification;

public class Example {
    // Find your Account SID and Auth Token at twilio.com/console
    // and set the environment variables. See http://twil.io/secure
    public static final String ACCOUNT_SID = System.getenv("TWILIO_ACCOUNT_SID");
    public static final String AUTH_TOKEN = System.getenv("TWILIO_AUTH_TOKEN");

    public static void main(String[] args) {
        Twilio.init(ACCOUNT_SID, AUTH_TOKEN);
        Verification verification = Verification.creator(
                "VAXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX",
                "+15017122661",
                "sms")
            .create();

        System.out.println(verification.getSid());
    }
curl -X POST "https://verify.twilio.com/v2/Services/VAXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX/Verifications" \
--data-urlencode "To=+15017122661" \
--data-urlencode "Channel=sms" \
-u $TWILIO_ACCOUNT_SID:$TWILIO_AUTH_TOKEN
		

Need help setting up phone number lookup?

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Stop fraud in its tracks without user signups grinding to a halt

Use Lookup and Verify together for a comprehensive solution that cuts costs, increases OTP conversions, and reduces fraud risk.

70% lower

cost-per-user and support costs with Verify’s real-time identity signals*

$62.7 million

saved by Verify Fraud Guard**

4.8 billion

user validations per year*

90% decrease

in user validation time with Lookup Identity Match*

Explore Verify

Build now, buy later. Start your free trial.

Reduce your fraud risk and build the secure experience you’ve always wanted. With Twilio Lookup API, you only pay for what you use and there’s no credit card required to start.

Start for free See Lookup API pricing

Woman in a pink blazer smiling and working at a computer in a dimly lit office

* Twilio Accolades Book, page 34, 35
** Total Verify Fraud Guard $62.7M+ in explicit savings from June '22 up to 01 Oct '24