SIM swap attacks are a type of fraud where a bad actor gains access to your cellular account through social engineering or bribery, allowing them to issue a new SIM card with your mobile number and gain access to your two-factor authentication (2FA) codes. To detect these attacks before sending an SMS OTP, Twilio's Lookup API offers real-time carrier data and can return information such as the carrier's name, MNC and MCC codes, and details about the last SIM swap. The API requires a Twilio account and carrier approvals before provisioning access. Users can query the API using their Account SID and Auth Token to detect SIM swaps in real-time, allowing them to take steps to prevent fraud and keep customers secure.