messages.dev

messages.dev is a REST API and TypeScript SDK that lets AI agents send and receive iMessage, RCS and SMS, with webhooks, reactions, typing indicators and managed infrastructure, plus a free sandbox of 50 messages per day.

messages.dev is a developer-focused messaging API that lets AI agents talk to people over iMessage, RCS and SMS through a single integration. Instead of wiring up separate carriers or protocols, a team sends and receives messages through one REST API or a TypeScript SDK, installed from npm, and the platform handles the delivery details behind it. The product is aimed at developers and startups building conversational agents, assistants and automated workflows that need to reach users in the apps they already open every day. A typical use is a personal assistant that answers a question such as what is on today's calendar, delivered as a native-looking text thread rather than a custom chat widget. Features that make the thread feel native include tapback reactions, typing indicators and read receipts, all supported across conversations. In practice, a developer creates an account in the web app, gets an API key and sends a first message from the SDK or a plain HTTP call. Incoming messages, reactions and receipts arrive through real-time webhooks, which the agent's own code consumes to decide what to reply. A sandbox environment provides 50 free messages per day for building and testing before going live. Provisioning, scaling and monitoring are run by the vendor, so the customer's work is limited to the agent logic itself. Security measures listed include end-to-end encryption, scoped API keys and webhook signature verification. Among alternatives, messages.dev sits between general SMS platforms, which are mature but built around phone-number messaging, and do-it-yourself iMessage bridges, which demand hardware and upkeep. Its narrow focus on agents and on blue-bubble style conversations is the main differentiator. Teams that only need plain SMS or voice, or that want a visual no-code builder, will find the scope tighter than broad communications suites. Production pricing is not described on the homepage, so cost planning requires checking the app or docs.