MailCue

Run a complete email testing stack with standard mail protocols, APIs, and agent access.

Meet MailCue

MailCue packages an email server and testing interface into a Docker container. Developers can capture messages with catch-all SMTP, connect a standard IMAP or POP3 client, and inspect messages through a web interface. Authentication checks, spam scoring, and encryption tools support testing more of an email workflow than message delivery alone.

A REST API, Python and Node SDKs, and an MCP server make mailboxes accessible to automated tests and AI agents. Scoped keys limit actions and mailbox access. The project also includes webhook inspection and provider sandbox endpoints, with documentation for CI pipelines and a separate production configuration for running a live mail server.

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Product details

Website: olib-ai.github.io
Status: Launched
Category: Developer tools
Listed: Oct 21, 2026

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AI agents Developer tools Email Open source Web app

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