Messaging API Glossary
Definitions for iMessage, RCS, A2P, CPaaS, and more.
Standard
RCS
Rich Communication Services. The next-gen SMS with read receipts, typing indicators, and rich media.
Learn more →Compliance
A2P Messaging
Application-to-Person messaging. How businesses send automated SMS — and why it requires 10DLC registration.
Learn more →iMessage
Blue Bubble
The iMessage indicator. Blue bubbles mean higher response rates, read receipts, and no carrier filtering.
Learn more →Developer
iMessage API
An API that lets developers send iMessages programmatically from any app or service.
Learn more →AI
MCP (Model Context Protocol)
Anthropic's open standard that lets AI models connect to external tools like Sendblue.
Learn more →Category
CPaaS
Communications Platform as a Service. The category that includes Twilio, Vonage, and Sendblue.
Learn more →Ready to build with Sendblue?
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