Unitpost

Unitpost, from Work Reactor Inc., is a messaging platform for the email and SMS a product sends. It offers a REST API, SMTP relay, nine SDKs, a CLI and an MCP server, and lets an AI agent build automations that the user approves before anything is sent.

What It Is

Unitpost combines transactional and marketing email with SMS on the same contacts, suppression and sending balance. Developers can send through a REST API, SMTP, or SDKs for Node.js, Python, Ruby, PHP, Laravel, Go, Java, Rust and .NET. Templates can be designed visually or written in code.

How the agent workflow works

A user describes a job in plain words, such as win-back, abandoned cart, failed payment, trial ending or appointment reminders. The in-product assistant, Unit, builds the automation from triggers, waits and send actions. Nothing sends until the user approves it, every step is logged, and runs can be paused or cancelled from the dashboard, the API or the agent. The site lists Automations as coming soon.

Agent and developer tooling

The MCP server exposes the same actions as the dashboard, such as sending, verifying a domain and building a segment, to Cursor, Claude and other MCP clients. An Agent Skills package installs the Unitpost skill into coding agents with one command. The CLI covers every API operation from a shell, with browser sign-in using OAuth 2.1 and PKCE.

Delivery and consent

The site states that consent is checked at send time, including unsubscribe, STOP and quiet hours. It also lists signed webhooks retried seven times over 19 hours, and domain records re-checked every minute. SMS covers 177 countries, with two-way messaging on US and Canadian numbers. A Migration Assistant imports from Resend, SendGrid, Mailgun, Postmark, Brevo and Loops using a read-only API key.