EmailEngine vs Mailjet

EmailEngine is a self-hosted email API that connects Gmail, Microsoft 365, and IMAP mailboxes through a unified REST API. It sends webhooks when mailbox messages or state change, and can send mail through the connected account’s SMTP server or provider API. Native integrations use the Gmail API and Microsoft Graph; authentication options include managed OAuth2, service accounts for Google Workspace, Microsoft 365 app-only access, and shared or delegated mailboxes. An optional MCP server, currently in beta, lets connected AI clients search, read, file, draft, and send email with approved access. The admin interface shows sync status and queue details, with a Prometheus endpoint and Grafana dashboard for operations. EmailEngine runs on the customer’s infrastructure, uses Redis for sync metadata, and fetches message bodies on demand rather than storing them. A server and Redis using the noeviction policy are required. The annual subscription is $1,450 a year, excluding VAT where applicable, and includes developer support; each installation can start a full-functionality 14-day trial without signup or a credit card.

Mailjet is an email marketing and API platform for creating, sending, and automating marketing and transactional messages. Marketing teams can use its drag-and-drop editor, forms, landing pages, segmentation, preference centers, personalization, A/B testing, and analytics. Automation workflows can send messages based on customer actions. Developers have a RESTful Email API, SMTP Relay, Parse API, Event API, SDKs, webhooks, and an MCP Server. Team features include shared workspaces, roles, approval flows, and collaboration. Mailjet lists more than 100 ready-to-use integrations and supports custom connections through its API. The free plan includes 6,000 emails per month, capped at 200 per day, and 1,000 contacts; signup does not require a credit card. Starter costs $9 a month and includes 8,000 emails monthly with no daily sending limit. Essential costs $19 a month, and Premium costs $29 a month. Unused email credits expire at the billing-cycle end, and additional sends after credits run out are billed.