Twilio Lookup API

Build secure experiences using data with Lookup API

Lookup API transforms your phone intelligence data into trusted interactions. Build onboarding and engagement experiences that improve delivery and mitigate risk seamlessly without user input.

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

Boku Mobile Identity is now part of Twilio

Twilio has acquired Boku Mobile Identity to forge one seamless customer identity and onboarding solution.
With Boku verification, every Twilio engagement enjoys unmatched security and performance.

Verify, secure, and optimize engagement with one integrated API

Lookup API adds a seamless layer of security to customer relationships using real-time phone data. Improve conversion and delivery rates, spot risk, and halt fraud. Then integrate with Twilio Verify, Programmable Messaging, and more to enhance your engagement solution with best-in-class security.


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Improve security, conversions, and delivery at once

Phone intelligence data being used to deliver a smooth, secure messaging experience.
Phone intelligence data being used to deliver a smooth, secure messaging experience.

Reduce risk and fraud

Protect against fraud with authoritative phone intelligence data. Lookup API uses real-time risk signals to detect fraud and trigger step-up authentication when needed. Determine if a number is valid by identifying the line type as mobile, landline, VoIP, temporary number, and more. Stop fraudulent SIM swaps and fake accounts for secure relationships at scale.

  • Integrate with Twilio Verify, Programmable Messaging, and more to secure uses cases for onboarding, engagement, and support.

  • Spot risk signals in real-time by requesting data packages from multiple sources for accuracy and fill rates without slowdown.

  • Secure accounts with high throughput for zero throttling, plus latency checks scaled to your contact list and message volume.

Use cases

Put up-to-date phone intelligence to work at scale

Improve message deliverability

Delivery errors frustrate users who expect real-time communications. Improve contact rates by validating a number before you send. Distinguish mobile numbers from landlines, format numbers correctly, and optimize SMS routing with carrier data for optimal delivery.

Personalize messaging and voice calls

Personalization is key to a quality customer experience. Identify inbound callers globally by determining the name associated with phone number to personalize engagement over SMS and voice calls, and enhance your marketing at any scale.

Enrich data and risk models

Businesses use customer data to enrich user profiles and understand risk. Access real-time user signals like phone line type, SIM tenure, connectivity status, carrier, and more to improve risk models, scrub contact lists, and make more accurate business decisions.

Mitigate fake accounts and takeovers

Stopping SIM swap fraud, fake account creation, account takeovers, and promo abuse is a business priority. Halt takeovers when you identify risk signals of compromised numbers. Mitigate fakery with Line Type Intelligence that spots suspicious virtual numbers.


Build trusted relationships upon real-time insights

  • Formatting and Validation

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

  • Network tower with signal
    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.

  • Call Forwarding

    Expose voice channel compromise and at-risk numbers with real-time access to the call forwarding status for mobile numbers. Only available in the UK.

  • 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.

“We’ve never had a reliability issue with Twilio, and I think that speaks to the nature of its scalability and reflects on every single product we’ve worked with Twilio on so far.”

Marcelo Oliviera VP of Engineering, Luma Health


Enhance your engagement solution with seamless security in one API

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