Twilio provides the communications infrastructure that businesses use to interact with their customers. The core product is a set of APIs that developers embed into their applications to send messages, make calls, and deliver emails. Common use cases include appointment reminders, order confirmations, two-factor authentication, marketing campaigns, and AI-powered voice agents. Twilio's main products span messaging (SMS, MMS, RCS, WhatsApp), voice, email (via SendGrid), and user authentication (Verify/Lookup). Twilio also offers Segment, a customer data platform (CDP) that consolidates customer data into unified profiles to enable personalized communications. Twilio organizes into two segments: Communications (~94% of revenue) and Segment (~6%). Revenue is primarily usage-based — Twilio earns more as customers send more messages or make more calls — making revenue closely tied to the underlying business activity of its customers. Twilio had over 402,000 active customer accounts as of end-2025, ranging from individual developers to large enterprises. Customers access the platform through self-service sign-up, a direct sales force, and ISV partners who embed Twilio's capabilities into their own products. Twilio's growth strategy centers on developer adoption, ISV partnerships, cross-selling additional products to existing customers, and capturing AI-driven use cases — particularly Voice AI, where revenue grew above 60% YoY in late 2025. Twilio has shifted from a growth-at-all-costs model toward profitability, completing $855M in share repurchases in FY25.