Overview
Plunk is an open-source email platform (AGPL-3.0, over 5,000 GitHub stars) that covers three jobs: transactional email through an API or SMTP, campaign broadcasts to lists or segments, and workflow automations with triggers, delays and conditions. All events land in one contact record, so a receipt, a newsletter and an onboarding sequence share the same data.
The hosted service is EU-hosted and GDPR compliant. The free plan sends 1,000 emails a month with all features and Plunk branding in the footer. The paid plan has no base fee and charges $0.001 per email, removes branding and lets you set a monthly spend cap. Contacts are unlimited on both.
You can also self-host the full platform with Docker Compose and keep all data on your infrastructure. Inbound email, custom domains with automatic DKIM, SPF and DMARC setup, dynamic segments and analytics are included everywhere.
Pricing and plans
Free tier · no card
Cloud free plan: 1,000 emails a month, all features, unlimited contacts, Plunk branding on emails
At the limit Stops at the limit Past the free allowance the API returns 402 and further sends are refused.
Their branding| Plan | Price | What you get |
|---|---|---|
| Self-hosted | Free (AGPL-3.0) | Docker Compose; no per-email cost from Plunk |
| Free | $0/mo | 1,000 emails/month, Plunk branding |
| Pay as you grow | $0.001 per email | No base fee, no branding, monthly spend cap, unlimited emails |
What it does
- Transactional API and SMTP
- Send receipts, password resets and event-driven email through the REST API with SDKs or SMTP.
- Workflow automation
- Visual builder for sequences with triggers, delays, conditions and branching.
- Campaigns
- Broadcasts to full lists or segments with scheduling and tracking.
- Dynamic segments
- Real-time segmentation from contact data and behavior.
- Inbound email
- Receive incoming email with webhook notifications.
- Self-hosting
- Deploy with Docker Compose under AGPL-3.0.
Strengths and limitations
Strengths
- Unlimited contacts at no cost
- No base fee; pay only per email
- Open source and self-hostable
- EU-hosted cloud
Limitations
- Free plan adds Plunk branding to emails
- At $1 per 1,000, costs more than SES-priced options at high volume
- No dedicated IP option mentioned
- No compliance certifications listed beyond GDPR
Who it suits
Good for
- SaaS founders wanting transactional plus lifecycle email in one tool
- Projects with large contact lists and modest sending
- Teams that want to self-host
Look elsewhere if
- High-volume transactional senders focused on per-email cost
- Teams that need a dedicated IP
Alternatives to Plunk
| Tool | From | Free option | Stages |
|---|---|---|---|
| Loops Lifecycle email for SaaS | $49/mo | Free tier | |
| useSend Open-source email platform on Amazon SES | $10/mo | Free tier | |
| Resend Email API for developers | $20/mo | Free tier | |
| Mailjet Email API, SMTP relay and campaign editor | $9/mo | Free tier | |
| Mailcoach Email marketing platform | $9.99/mo | ||
| Notifuse Open-source email platform | $19/mo |
Questions
Is Plunk free?
The cloud free plan includes 1,000 emails a month with Plunk branding, and self-hosting is free.
How much does Plunk cost?
$0.001 per email with no base fee on the paid plan, and contacts are unlimited.
Is Plunk open source?
Yes, it is AGPL-3.0 licensed and can be self-hosted with Docker Compose.
Where is Plunk hosted?
The hosted service is EU-hosted and GDPR compliant.
Sources read for this page