WildDuck Mail Server
WildDuck Mail Server: A flexible open-source mail server for developers building distributed deployments. Ranked #89 of 178 in Email Hosting by our editors (5.3/10); pricing: Open source; best for developers building scalable self-hosted mail.
At a glance
- Editor score5.3 / 10
- PricingOpen source
- Best forDevelopers building scalable self-hosted mail
- Paid fromFree
- Facts checked22 Sep 2026
Where it wins
- Horizontal scaling supports distributed deployments across multiple instances
- REST API manages accounts, mailboxes, messages, filters, and domains
- IMAP4rev1, POP3, migration tools, and strong authentication controls
Where it doesn't
- Requires self-hosting, deployment, and ongoing infrastructure management
- Its open-source model leaves hosting and quota design to the operator
- No mobile apps, calendar, or hosted mailbox experience
Our verdict on WildDuck Mail Server
WildDuck Mail Server is open-source, self-hosted email server software for developers and teams building scalable mail infrastructure. It provides IMAP4rev1 and POP3 access, stores messages in MongoDB, and exposes REST endpoints for managing accounts, mailboxes, messages, filters, and domains. The product is designed for deployments with approximately 1,000 or more accounts that need horizontal scaling across multiple instances.
WildDuck's open-source model puts the infrastructure design in the operator's hands rather than dividing features into hosted paid plans. Its ecosystem includes MongoDB and Redis, with Haraka and ZoneMTA supporting a complete mail stack, Rspamd for mail processing, and OpenSearch for search-oriented deployments. Webhooks and real-time event notifications can connect mail activity to surrounding systems, while sharding and attachment deduplication support larger storage architectures. Developers choosing WildDuck should be comfortable assembling and operating these components.
Deployment can be manual, containerized with Docker, or integrated into a broader mail stack. Security controls include TOTP and WebAuthn two-factor authentication, DKIM, domain aliases, and domain access controls. Maildir and IMAP-based import tools support mailbox migration. WildDuck is a strong fit for teams that need API-driven administration, distributed storage, and control over their mail environment. It is less suitable for organizations seeking a ready-to-use hosted mailbox service, built-in calendar capabilities, or a consumer-style mobile experience.
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WildDuck Mail Server pricing
WildDuck Mail Server fact sheet
| Free plan | Not verified |
|---|---|
| Paid from | Free |
| Storage per mailbox | Not verified |
| Email aliases | Not verified |
| Attachment limit | Not verified |
| IMAP/POP support | Yes |
| Mobile app access | Not verified |
| Calendar included | Not verified |
| Migration tools | Yes |
| Deployment | Self-hosted |
| Platforms | Windows, Linux |
| Support | Docs |
| Built for | Mid-market, Enterprise (editorial estimate) |
| Integrations | 6 integrations: MongoDB, Redis, Haraka, ZoneMTA, Rspamd, OpenSearch |
| Pricing | Open source |
| Website | docs.wildduck.email |
| Facts checked | 22 Sep 2026 |
WildDuck Mail Server integrations
WildDuck Mail Server lists 6 integrations on its own site.
- MongoDB
- Redis
- Haraka
- ZoneMTA
- Rspamd
- OpenSearch
Alternatives to WildDuck Mail Server
- Zoho MailA flexible business email suite with a free plan, low-cost entry tier, and migration support.9.4
- Microsoft Exchange OnlineA deep Exchange service for organizations centered on Outlook and administration.9.2
- Google WorkspaceA full Gmail-based collaboration suite for organizations that need more than email.9.1
See all WildDuck Mail Server alternatives →
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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