Chert

Chert, from Y Combinator-backed Chert Technologies Inc. with backing from OpenAI, Z Fellows, and Betafund, provides API infrastructure for sending and receiving iMessage messages at scale, enabling businesses to build AI agents and automate workflows through Apple's iMessage protocol rather than traditional SMS. Native iMessage delivery shows messages as blue-bubble threads from verified numbers, two-way messaging supports both outbound campaigns and inbound handling with full conversation context, and intelligent fallbacks automatically route to SMS or RCS when recipients aren't on iMessage. Multi-tool integration connects to Salesforce, HubSpot, Slack, and Attio via REST API and webhooks, and conversational workflows enable typing indicators, reactions, and reply context for AI agents and human follow-up.