Build an allow list to filter sign ups by country with Twilio Lookup

To filter sign-ups by country, developers can use the Twilio Lookup API with a country code allow list. This approach is useful for ensuring compliance requirements, reducing fraud, or controlling onboarding pipelines. The Lookup API provides tools for validating phone numbers and includes country codes in the response, making it easy to build an allow list. Developers can start by setting up their Twilio account, installing Node.js and the Twilio CLI, and then using a serverless project template to test the solution. They can add an allow list to their sign-up form by modifying the code and updating the project accordingly. The Lookup API also has other uses beyond country filtering, such as blocking specific countries or detecting line type and carrier.