The Texas Regional Advisory Council and the Texas Division of Emergency Management partnered with Twilio to use Flex as a hybrid hotline and phone system for COVID-19 vaccine distribution logistics. They needed to provide 24/7 inbound calls about vaccination logistics, as well as direct inward dial (DID) capabilities for emergency responders to coordinate with healthcare providers on personal numbers. The team deployed a solution that handled several thousand calls in one day, using Flex's TaskRouter workflow to match incoming calls to the right agent based on their DID phone number. They created a Twilio Studio flow to handle inbound calls from DID numbers and assigned phone numbers to TaskRouter workers through SSO syncing. Finally, they developed a Flex plugin to enable agents to make outbound calls from their own DID numbers, with customizable caller ID and display of agent's number in the interface.