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MailKite Server vs Postmark

MailKite Server

mailkite.dev

Postmark

postmarkapp.com

Side by side

FigureMailKite ServerPostmark
Price fromFree$5/mo
Free planYesYes
Free trial—Yes
Open source——
WebYesYes
APIYesYes
Self-hostedYes—
Plans published18
Spec score · Email APIs8.4 (#8)8.6 (#6)
IntegrationsMailKite lists official SDKs for Node.js, Python, Ruby, Go, PHP, Java, C#, and Rust, plus a CLI, an MCP server, and SMTP relay integrations.Official integrations include Slack, Zapier, Stripe, WordPress, Supabase, Bubble, Craft CMS, Netlify, and Gravity Forms.
SecurityServer components use HMAC-authenticated HTTP endpoints, and inbound webhook deliveries are signed and retried.Postmark supports TLS and HTTPS, DKIM, SPF, DMARC, two-factor authentication, API permission controls, penetration testing, and DDoS protection.
SupportThe self-hosted server page directs users to GitHub discussions and setup documentation; it describes human support as a MailKite Cloud offering.Postmark offers support by email, live chat, and one-on-one calls and reports a 95% customer happiness rating.

Plans

MailKite Server

  • MailKite Server (AGPL-3.0)Free

MailKite Server pricing →

Postmark

  • FreeFree
  • Basic$15 a month
  • Pro$16.50 a month
  • Platform$18 a month
  • Custom activity retention$5 a month
  • DMARC monitoring$14 a month
  • Dedicated IP$50 a month
  • High-volume plansPriced on request

Postmark pricing →

In their own words

MailKite Server

MailKite Server has no write-up on Specifiction yet; its figures are above.

Visit mailkite.dev

Postmark

Postmark delivers and tracks application email as an alternative to SMTP or Sendmail. It separates transactional and broadcast messages into different Message Streams and IP infrastructure. Developers can send through REST API, SMTP, or multi-region SMTP routing, with official libraries for Node.js, Python, Rails, Ruby, PHP, and.NET. Inbound messages can be converted to JSON and sent to a webhook URL. Tracking includes delivery, bounces, spam, opens, and links, with event webhooks. Editable responsive templates cover transactional messages such as password resets, receipts, and invitations. The free Developer plan costs nothing, provides 100 emails per month, permits no overages, and does not expire. Basic starts at $15 a month for 10,000 emails per month; extra emails cost $1.80 per 1,000 and are calculated at the end of the billing cycle. Unused emails do not roll over. Postmark lists API and web access. Its iOS app was sunset in June 2025 and is no longer supported.

Visit postmarkapp.com