Plunk vs Postmark
Plunk
useplunk.com
Postmark
postmarkapp.comSide by side
| Figure | Plunk | Postmark |
|---|---|---|
| Price from | Free | $5/mo |
| Free plan | Yes | Yes |
| Free trial | — | Yes |
| Open source | — | — |
| Web | Yes | Yes |
| API | Yes | Yes |
| Self-hosted | Yes | — |
| Plans published | 4 | 8 |
| Spec score · Transactional email services | 8.1 (#23) | 9.2 (#1) |
| Spec score · Email APIs | 7.6 (#23) | 8.6 (#6) |
| Spec score · Transactional Email Software | 7.8 (#31) | 8.7 (#7) |
| Free plan | Yes | Yes |
| Integrations | Plunk offers a REST API, SDKs including Node.js and Python, SMTP support, webhooks, and an MCP server that works with MCP clients such as Claude Code, Claude Desktop, and Cursor. | Official integrations include Slack, Zapier, Stripe, WordPress, Supabase, Bubble, Craft CMS, Netlify, and Gravity Forms. |
| Support | The maker invites customer feedback and lists a Discord community on its site. | Postmark offers support by email, live chat, and one-on-one calls and reports a 95% customer happiness rating. |
Plans
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
In their own words
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.