Plunk
Open-source email platform for transactional email, campaigns and automated workflows on one contact list.
Updated · AppBreakup editorial · Web, Self-hosted
Is Plunk free?
Yes, free and open source
- Price:
- $0.001 per email
- Free plan:
- 1,000 emails/month
Checked on Plunk's site Nov 8, 2026
Full Plunk pricing and plansSwitch from Plunk to
All 6
ResendStarting price: $20 a month for 50,000 emails (Pro)
PostmarkStarting price: $15 a month (Basic, 10,000 emails)
Twilio SendGridPaid
- Verified facts
- 5 of 5
- Alternatives ranked
- 6
- Approved reviews
- 0
- Visits sent from here
- 0
About Plunk
Plunk is an open-source email platform that combines three things most teams buy separately: transactional sending (password resets, receipts), marketing campaigns to segments, and event-triggered workflows with delays and conditions. Everything works against one contact list, so a receipt, a newsletter and a reply show up in a single history per contact. Developers send through a REST API or SMTP relay, and there's also inbound email, email validation, open and click tracking, a visual and HTML editor and an MCP server so AI agents can manage campaigns with approval. The hosted cloud runs in the EU. Pricing is by email sent rather than by contact: a free plan covers a small monthly volume with Plunk branding, and the paid plan charges per email with every feature included. The code is AGPL-3.0, and you can self-host it with Docker. It suits startups and indie developers who want one tool for product and marketing email.
Best for: Startups and indie developers wanting transactional and marketing email in one open-source tool.
Plunk pricing (checked Nov 8, 2026)
Each line is quoted from Plunk's own site, with the page it came from.
| Plan or term | What it says | Checked | Source |
|---|---|---|---|
| Free plan | 1,000 emails/month | Nov 8, 2026 | useplunk.com |
| Price | $0.001 per email | Nov 8, 2026 | useplunk.com |
Pros and cons
What works
- Transactional, campaign and workflow email on one contact list
- Pay per email with unlimited contacts
- Open source and self-hostable with Docker
- EU-hosted cloud option
Why people leave
- Free plan adds Plunk branding and caps monthly sends
- Smaller company and ecosystem than SendGrid or Mailchimp
- AGPL licence can be restrictive if you modify and offer it as a service
Plunk vs Resend, Postmark and Twilio SendGrid
From each app's listing and the prices verified on its own site. A dash means we haven't verified it yet.
| Attribute | Plunk | Resend | Postmark | Twilio SendGrid |
|---|---|---|---|---|
| Pricing | Open source | Free plan + paid | Free plan + paid | Paid |
| Verified price | $0.001 per email | $20 a month for 50,000 emails (Pro) | $15 a month (Basic, 10,000 emails) | — |
| Free plan | 1,000 emails/month | Yes, 3,000 emails a month (100 a day) | Yes, 100 emails a month | No |
| Open source | No | No | No | No |
| Self-hostable | No | No | No | No |
| Platforms | Web, Self-hosted | Web | Web | Web |
Top Plunk alternatives
See all 6- 1Resend68.8
Developer-loved sending API with React Email support and a free tier.
- 2Postmark61.8
Strong deliverability focus for transactional email, with separate streams for broadcasts.
- 3Twilio SendGrid59.4
Large-scale sending with mature tooling, for teams that outgrow a small provider.
- 4
Mailgun57.5Established email API with validation and inbound routing at high volume.
- 5
Loops54.4Product and marketing email for SaaS in one tool, with a more polished hosted editor.
Why people left Plunk
In reviewers' own words, from reviews of the apps they moved to. These are their opinions, not ours.
No switching stories yet. If you moved away from Plunk, review the app you switched to and tell us why.
Reviews
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Write a review of Plunk
Plunk: common questions
What is Plunk?
Plunk: Open-source email platform for transactional email, campaigns and automated workflows on one contact list. Best for startups and indie developers wanting transactional and marketing email in one open-source tool. Available for Web, and you can host it yourself.
Is Plunk free?
Yes. Plunk is free, open-source software.
How much does Plunk cost?
Plunk is free and open source. Free plan: 1,000 emails/month; Price: $0.001 per email. Checked on Plunk's own site, November 2026.
Is Plunk open source?
No, Plunk is not open source.
What platforms does Plunk run on?
Plunk is available for Web and Self-hosted.
What are the best alternatives to Plunk?
The highest-ranked Plunk alternatives right now are Resend, Postmark and Twilio SendGrid. See the full ranked list for pricing, platforms and verified facts.
Plunk vs Resend: what's the difference?
Plunk is free and open source; Resend is free with paid plans. Verified prices: Plunk $0.001 per email, Resend $20 a month for 50,000 emails (Pro). Both run on Web.