Mailly

Mailly is a two-way email service for AI agents and applications. Each inbox gets an address on mailly.site, or a custom domain on a paid plan, and incoming messages, outgoing messages and replies are kept together in one conversation thread. An agent can read the full thread, and a hosted agent can prepare reply drafts that you edit and approve before anything is sent.

The product can be connected through a remote MCP endpoint, an HTTP API, a CLI or SMTP. Inbound mail can be delivered to your own receiver with signed webhooks that are retried on failure. Campaigns handle audience outreach from synced contacts and static or dynamic lists, and Workflows handle lifecycle messages triggered by events, with wait steps. Delivery, bounce, complaint and unsubscribe events are recorded so you can inspect what happened to each message.

Mailly is aimed at developers and teams who want an agent or application to handle email without losing human oversight. Hosted agents currently draft only, so sending from an agent requires your own application to call the API or CLI and apply its own send controls.