Plunk
Plunk: A flexible email API with workflows, inbound processing, and self-hosting. Ranked #6 of 32 in Email APIs by our editors (8.6/10); pricing: Free plan; best for open-source teams needing flexible email workflows.
At a glance
- Editor score8.6 / 10
- PricingFree plan
- Best forOpen-source teams needing flexible email workflows
- Free planYes
- Paid from$0.001/unit usage-based
- Inbound emailYes
- Facts checked23 Sep 2026
Where it wins
- REST API, SMTP relay, and inbound email processing
- Workflows, campaigns, templates, segmentation, and analytics
- Free tier plus Docker Compose self-hosting
Where it doesn't
- Free plan is limited to 1,000 emails per month
- Paid cost varies with email volume
- Self-hosting requires Docker Compose setup
Our verdict on Plunk
Plunk is an open-source email platform for developers and teams managing transactional email, marketing campaigns, workflow automation, and contact operations. It combines REST API sending, SMTP relay, inbound email processing, reusable templates, dynamic segmentation, event tracking, and analytics in one product. Teams can use the hosted service or self-host the open-source edition with Docker Compose, making it a fit for organizations that want control over their email infrastructure and workflow design.
The feature set covers both application and marketing use cases. Transactional messages can be sent through the REST API or SMTP relay, with TLS support on ports 465 and 587. Inbound email receiving and event processing extend the platform beyond outbound delivery. Templates support visual and HTML editing, while workflows provide triggers, delays, conditions, and webhook actions. Campaign broadcasts, contact management, and analytics for opens, clicks, bounces, and unsubscribes make Plunk broader than a narrowly focused sending API. Node.js, Python, SMTP clients, and MCP clients are listed integration options.
Pricing is structured around a free plan and usage-based paid sending. The Free plan includes 1,000 emails per month, unlimited contacts, transactional emails, workflow automation, campaign broadcasts, and custom domains. Pay as you grow costs $0.001 per email and adds unlimited emails, unlimited contacts, transactional, campaign, and workflow sending, no Plunk branding, and a monthly spend cap. That model suits teams whose volume changes over time, while the free limit may be restrictive for larger senders. Choose Plunk for flexible workflows, open-source availability, and self-hosting; consider an alternative if you need a conventional fixed subscription or prefer a narrowly focused email delivery service.
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Plunk pricing
All 2 Plunk plans and prices →
Plunk fact sheet
| Free plan | Yes |
|---|---|
| Paid from | $0.001/unit usage-based |
| Monthly send limit | Not verified |
| Inbound email | Yes |
| Delivery event webhooks | Yes |
| SMTP relay | Yes |
| Email templates | Yes |
| Dedicated IP option | Not verified |
| Deployment | Cloud, Self-hosted |
| Platforms | Web |
| Compliance & security | GDPR |
| Support | Email, Community, Docs |
| Built for | Solo, Small business, Mid-market (editorial estimate) |
| Integrations | 4 integrations: Node.js SDK, Python SDK, SMTP-compatible clients, MCP clients |
| Pricing | Free plan (source) |
| Website | useplunk.com |
| Facts checked | 23 Sep 2026 |
Plunk integrations
Plunk lists 4 integrations on its own site.
- Node.js SDK
- Python SDK
- SMTP-compatible clients
- MCP clients
Alternatives to Plunk
- MailgunA mature email API with broad sending, inbound routing, tracking, and deliverability tools.9.7
- Twilio SendGrid Email APIA mature email API with broad developer features, but no ongoing free plan.9.3
- MailjetA broad email platform combining APIs, automation, campaigns, and collaboration.9.1
Plunk vs the competition
- Plunk vs Twilio SendGrid Email API
- Plunk vs Mailjet
- Plunk vs Scaleway Transactional Email
- Plunk vs Netcore Email API
Compare Plunk with any tool side by side →
Also Ranked In
Plunk is ranked in 2 of our directories.
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Featured on iTechGuides
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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