The Authy API, which is being maintained for the time being, will be evolving into the Verify API with new features such as improved developer experience, programmable rate limits, and a new authentication method using Twilio credentials. The Verify API offers better tools including Twilio helper libraries in multiple programming languages, an improved console interface, and enhanced error handling and insights. Applications are now configured as Services rather than applications, and users must use both their Twilio credentials and a Service SID to manage verifications. The new API has different error codes and requires E.164 formatted phone numbers for SMS verifications, with best practices including using the Lookup API to convert national format numbers to E.164 format and defining allowed countries. Migrating from Authy to Verify also involves deleting Authy users from legacy applications and potentially testing rate limits without getting blocked.