Twilio is a cloud communication platform that helps protect its customers from getting penalized for violating global telecommunications regulations. The company offers different types of phone numbers, including local numbers, toll-free numbers, mobile numbers, national numbers, and multi-function numbers, each with varying meanings in different countries. Twilio also supports short codes, which are pre-approved by carriers and allow high throughput, but not all countries offer SMS messaging through these numbers. To send messages internationally, customers can use sender IDs, which allow them to send messages using alphanumeric characters instead of a phone number. Sender IDs come with varying requirements, such as registration with local authorities in some countries, and have different usage guidelines depending on the country. When choosing between phone numbers or sender IDs, customers must consider their specific use case, taking into account factors like high-volume messaging, time-sensitivity, and message deliverability.