CheckThatPhone is a phone number validation API for US and Canadian numbers. A single REST call returns carrier, line type, portability, deliverability, geolocation, and timezone from live carrier data, with optional TCPA litigator screening and a free state do-not-call scrub. Businesses use it for compliance-safe calling and texting, lead validation, fraud prevention, and CRM data hygiene — via the API, bulk CSV upload, or official Node.js and Python SDKs. A free tier with 500 lookups per month makes it easy to evaluate before upgrading.