EmailEngine

EmailEngine lets software teams build email features into their products without writing IMAP, MIME or OAuth2 code. Installed on the customer's own infrastructure with Redis, it connects to Gmail, Google Workspace, Microsoft 365, Outlook.com and any IMAP server, manages OAuth2 tokens, and exposes all accounts through one REST API. It keeps an open connection to every mailbox and pushes signed webhooks when messages arrive or change, and it sends mail through users' own servers with correct threading, templates, scheduling and bounce handling. An MCP server gives AI agents controlled mailbox access. It is sold as a flat annual license with unlimited mailboxes, or a perpetual enterprise license, to CRM, helpdesk, SaaS and AI product teams.