Cadence

Overview

Cadence, a service of Salus, Inc., is an RCS Business Messaging API designed to be driven by AI agents. An agent opens a conversation over Google RBM with rich cards and quick-reply chips, and Cadence falls back to branded SMS when the recipient cannot get RCS. Brand verification, carrier readiness and launch run over the API, with no sales call. The site labels the product beta. It has no iMessage, WhatsApp or voice.

Key features

• Conversation API: open, send, close, with typed chip replies that read the same on RCS and SMS
• Automatic RCS to SMS fallback, reported as an event
• Server-run flows that answer replies without your process running
• HMAC-signed webhooks, an SSE event stream and polling
• TypeScript SDK and an MCP server (local or hosted with OAuth)
• Sandbox keys that simulate delivery and inbound replies
• Opt-in records and STOP/HELP handling built in

Pricing

Building and testing are free, including real RCS to your own test devices. Going live costs $250 a month per brand with one agent, plus $100 a month per extra agent. Usage is 10 cents per RCS conversation (a 24-hour session) and 5.5 cents per SMS. Registration and vetting fees are waived; carrier fees pass through at cost.

How it compares to Linq

Linq sends iMessage, RCS and SMS from managed phone lines; Cadence sends RCS from a branded agent with SMS fallback and no iMessage. Linq charges a flat fee from $260 a month with no per-message fees, while Cadence charges $250 a month per brand plus per-conversation and per-message usage. Both offer a TypeScript SDK, an MCP server and HMAC-signed webhooks. Linq reports SOC 2 Type II; Cadence publishes no compliance reports.

Best for

Developers building AI agents that start structured conversations with opted-in US consumers, such as reminders and check-ins, over RCS.

Sources

• cadencercs.com
• cadencercs.com/llms.txt
• cadencercs.com/docs
• cadencercs.com/customer-terms
• cadencercs.com/privacy.html
• cadencercs.com/guides/rcs-from-an-ai-agent
• api.cadencercs.com/openapi.json
• npmjs.com/package/@cadencercs/sdk
• npmjs.com/package/@cadencercs/mcp