Glossary
Messaging API
An interface for sending and receiving messages from code. The phrase covers two quite different products, and picking the wrong one is a common mistake in early architecture.
General definition
Messaging API is a general term for any API that lets an application send, receive and manage messages. In practice it names two categories of product that solve different problems.
1. Channel messaging APIs deliver messages to people on channels the business does not own: SMS and MMS, WhatsApp Business, RCS Business Messaging, Facebook Messenger, Telegram and similar. They are used for notifications, one-time passcodes, marketing and customer service on the customer’s preferred channel. The provider handles carrier and platform relationships, sender registration, message templates and per-message pricing, and the conversation lives on the third-party platform under its rules.
2. In-app chat APIs provide messaging inside your own product: user and room management, sending and fetching messages, attachments, presence, read state, moderation, and webhooks or events for your backend. The conversation is yours: your users, your data, your interface. The typical building blocks are a REST API for provisioning and history, a real-time transport (WebSocket, XMPP or a proprietary socket) for live delivery, client SDKs, and event hooks. Products in this category are usually paired with a Chat SDK that wraps the API with UI components.
How to choose:
- Need to reach people where they already are, with no app install, and can accept per-message cost and platform policies: a channel messaging API
- Need conversations inside your app or portal, with control over data, retention, identity and compliance: an in-app chat API
- Need both, for example in-app support chat with an SMS nudge when the user is offline: pick an in-app platform that can trigger outbound channel messages through webhooks, rather than trying to build the app experience on a channel API
- Regulated data (health, financial) rarely belongs on a consumer channel; an in-app API on infrastructure you control is the usual answer
In the Ethora ecosystem
Ethora is the second kind. Its messaging API combines a REST layer for apps, users, rooms, messages and files with XMPP over WebSocket for real-time delivery, webhooks for events, and an MCP server so that AI assistants and agents can provision apps, users and rooms through the same capabilities. End users can be created from your backend so they never see a separate login, and the server-side archive, retention settings, audit trail and Trust and Safety moderation apply to every message that passes through.
It does not send SMS or WhatsApp messages itself. When an outbound channel is needed, the usual pattern is a webhook or event from Ethora triggering a channel provider from your own backend, keeping the in-app conversation as the system of record. The same API also carries AI agent messages, so a support room can mix human staff, users and agents without a second integration.
