Twilio's Trusted Activation suite of products offers customizable verification solutions to optimize conversions and ensure account security. The Verify and Lookup APIs validate user identities with possession factors and authoritative mobile carrier signals, accelerating verification throughout the customer journey. With over 3.5 billion verifications sent annually, Twilio provides extensive documentation and helper libraries in multiple coding languages for developers. This guide covers common use cases, integrating with existing applications, consulting partners, contracting with or hiring a developer, architecting account security applications, sign-ups, upgrades, and funding accounts, geographic differences, pricing information, compliance and regulatory considerations, and building on Twilio.