Plunk

What is Plunk?

Plunk is an open-source email platform built for developers who don't want their email costs to creep up as their contact list grows, the way per-contact pricing on tools like Mailchimp does. It handles both transactional and marketing email from a single platform, with pricing based on emails sent rather than how many contacts you're storing. Since it's open-source, you can self-host it entirely if you'd rather not depend on a hosted service at all.

Key features

• Combined transactional and marketing email in one tool instead of needing two separate providers
• Per-email pricing instead of per-contact pricing, so a growing list doesn't automatically mean a bigger bill
• Self-hostable, open-source codebase for teams that want full control or to avoid vendor lock-in
• API and SDKs for sending transactional email programmatically
• Basic audience segmentation and campaign tools for marketing sends

Who it's for

A good fit for indie developers and small teams who want a Resend or Mailchimp alternative without per-contact pricing anxiety, especially if self-hosting appeals to you. If you need the deliverability reputation and polish of a larger, longer-established provider, a more established transactional-only tool may be the safer bet.

Pricing

Low, usage-based pricing per email sent, with a self-hosted open-source option that's free aside from your own infrastructure costs. Check the tool's site for current rates.