Haraka

At a glance

• Editor score
  6.3 / 10
• Pricing
  Free plan
• Best for
  Extensible SMTP filtering and routing
• Free plan
  Yes
• Paid from
  Free
• License model
  Open-source
• Facts checked
  21 Sep 2026

• Where it wins

  • Modular plugins expose SMTP transaction hooks and custom controls.
  • Supports authentication, DKIM, queueing, filtering, and outbound delivery.
  • Integrates with SpamAssassin, Rspamd, ClamAV, Redis, LDAP, and SMTP.

• Where it doesn't

  • Does not provide IMAP or POP3 access.
  • Focused on SMTP rather than mailbox storage or webmail.
  • Requires a plugin-driven approach for specialized mail workflows.

Our verdict on Haraka

Haraka is an open-source SMTP mail transfer and submission server written in Node.js. It is aimed at organizations and developers that need control over SMTP transactions, authentication, recipient validation, routing, relay behavior, filtering, queueing, and delivery. Its role is deliberately focused: Haraka handles mail transfer and submission rather than mailbox storage, webmail, or user access through IMAP or POP3. That makes it a fit for custom mail infrastructure where SMTP control matters more than an all-in-one mailbox product.

The main strength is its modular plugin architecture. SMTP transaction hooks let teams shape processing around authentication, DKIM, recipient validation, routing, relay controls, and message filtering. Haraka also supports outbound mail queueing and delivery, giving the server a defined path from accepted messages to external SMTP servers. Its integration set extends that design: SpamAssassin and Rspamd support filtering workflows, ClamAV supports malware scanning, Redis and LDAP connect surrounding services, and DKIM, SPF, and SMTP support common mail controls and delivery patterns. The result is a specialized foundation for organizations that want to compose their own mail-handling pipeline.

Haraka is free and open-source, so its value is primarily in flexibility rather than packaged mailbox functionality. Choose it when extensible SMTP filtering, routing, authentication, and delivery are the central requirements. Choose a different product when the mail system must also provide stored mailboxes, webmail, IMAP, or POP3 access. Its narrow scope is an advantage for SMTP-focused deployments, but it makes Haraka less suitable as a complete end-user email service.

Your product? Our editors can test Haraka in depth and publish a review, labelled as paid · from $149/mo →

Haraka pricing

Haraka fact sheet

Haraka integrations

Haraka lists 8 integrations on its own site.

• SpamAssassin
• Rspamd
• ClamAV
• Redis
• LDAP
• DKIM
• SPF
• SMTP

See all Haraka integrations →

Alternatives to Haraka

• Microsoft Exchange OnlineA Microsoft-centric hosted mailbox service with Outlook, archiving, compliance, and migration tools.9.3
• Zimbra CollaborationA broad open-source suite for organizations that need email, collaboration, and deployment control.9.1
• IceWarpA broad hosted email suite with collaboration, migration tools, and self-hosted deployment.9.0

See all Haraka alternatives →

Featured on iTechGuides

Haraka is listed in our Mail Server Software directory. Add the badge to your site — it links back to this page.

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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Last updated 7 Oct 2026 · How we research and update