Unified REST API
Use a single HTTP REST API with JSON payloads to send and receive email without dealing with IMAP internals, provider-specific APIs, or encoding details.
EmailEngine
RivendicaEmailEngine is a self-hosted email API with a unified REST interface for IMAP, SMTP, Gmail API, Microsoft Graph API, webhooks, OAuth2, and hosted authentication.
Overview
EmailEngine is a self-hosted email API for developers and businesses that need programmatic access to existing mailboxes. It provides a unified REST interface for working with IMAP, SMTP, Gmail API, and Microsoft Graph API, while handling the protocol and provider complexity behind the scenes.
The product is designed to connect to user email accounts, keep those accounts monitored, and notify your application when messages or account state changes occur. The source positions it as a way to build email-enabled features without assembling your own mail libraries or wiring each provider separately.
Features
Webhook Notifications
Receive real-time notifications when inboxes change, including incoming mail, deleted mail, and other account updates.
OAuth2 Integration
Connect Gmail and Outlook accounts through OAuth2, with support for either self-managed token renewal or EmailEngine-managed renewal.
OAuth2 Proxy for IMAP and SMTP
Authenticate IMAP and SMTP clients through EmailEngine while it handles the OAuth2 connection in the background, acting as a bridge for modern mail accounts.
Hosted Authentication
Use hosted authentication forms so users can authorize their email accounts and return to your app after setup completes.
Monitoring and Logging
Expose metrics through a Prometheus endpoint and use multiple logging modes, including full IMAP transaction logs, for debugging and monitoring.
Use Cases
SaaS and CRM integrations
Add email account connectivity to a SaaS product or CRM so users can link inboxes and surface correspondence inside your app.
Support mailbox automation
Build customer support or info-mail workflows that turn incoming messages into tickets, tasks, or automated follow-up actions.
Email hosting and webmail interfaces
Create hosted or customized webmail-style experiences for customers of an email hosting platform or web agency client.
Modern email account setup
Use OAuth2 authentication, hosted forms, and proxy features to connect Gmail, Outlook, Microsoft 365, or IMAP/SMTP accounts with less custom protocol work.
Event-driven integrations
Route mailbox events into Slack, Discord, Zapier, or other systems using webhook filters and output mapping for downstream processing.
Pros and Cons
Pros
- Unifies IMAP, SMTP, Gmail API, and Microsoft Graph API behind one REST API.
- Supports real-time webhooks for mailbox and message events.
- Offers OAuth2 support for Gmail and Outlook, including hosted authentication flows.
- Includes options for monitoring and detailed logging, including full IMAP transaction logs.
- Does not charge per connected mailbox according to the source.
Cons
- Pricing details are not available on the pricing page in the provided source set.
- The source supports a limited set of mail access methods and explicitly says POP3, ActiveSync, and EWS are not supported.
- EmailEngine requires Redis and a self-hosted deployment, so it is not a no-infrastructure SaaS service.
FAQ
Who is EmailEngine for?
EmailEngine is intended for developers and businesses that need to connect software to existing email accounts. The source highlights use cases such as help desks, CRM systems, SaaS apps, and email automation workflows.
How does EmailEngine work?
EmailEngine maintains open connections to registered accounts, listens for changes, and turns API requests into the corresponding mail server commands. It also sends webhook notifications when account events occur.
Is there a trial or license requirement?
Yes. The source says you can start a free 14-day trial from the dashboard without a license key. After the trial expires, EmailEngine stops processing accounts until a valid commercial license is available.
What does EmailEngine require to run?
EmailEngine requires Redis as its caching database. The source recommends a reasonably recent Redis version and low latency between Redis and EmailEngine for best performance.
Which email protocols does EmailEngine support?
EmailEngine supports IMAP and SMTP, along with the Gmail API and Microsoft Graph API. The source says POP3, ActiveSync, and Exchange Web Services are not supported.
Quick Facts
- Category
- Developer Tool
- Deployment
- Self-hosted
- Primary users
- Developers and businesses
- Source domain
- emailengine.app
- Core workflow
- Connect accounts, send and receive mail, and react to events via API and webhooks
- Supported providers
- IMAP, SMTP, Gmail API, Microsoft Graph API