The MailerLite alternative
that bills per email

The main difference is that Plunk is open-source and self-hostable, while MailerLite is proprietary SaaS. Plunk uses pay-per-email pricing versus MailerLite's pay-per-subscriber model. Both are developer-friendly, but Plunk is API-first with full code transparency, while MailerLite focuses more on visual email builders with good API support.

It depends on your usage pattern. MailerLite charges based on subscriber count (paid plans start at $12/month), while Plunk charges per email sent. If you have a large subscriber list but send infrequently, Plunk is typically cheaper. If you email your entire list frequently, costs are similar. The key difference is predictability: Plunk only charges for actual usage.

Yes. Plunk is open-source (AGPL-3.0) and can be self-hosted using Docker. This gives you full control over your data, infrastructure costs, and compliance requirements. MailerLite is cloud-only with no self-hosting option. Self-hosting is ideal for privacy-sensitive use cases or cost optimization at scale.

Plunk has a visual editor and an HTML editor side by side, with contact fields and fallbacks. MailerLite excels at visual drag-and-drop building for non-technical users. If you're a developer who prefers code-based templates, Plunk is better. If you need rich visual builders for marketers, MailerLite is better.

Both have modern REST APIs, but Plunk's API is designed with developers as the primary user. Plunk prioritizes API-first workflows, making it easier to integrate email into your application. MailerLite has a good API but is built UI-first with API as secondary. For programmatic email sending and automation, Plunk offers a superior developer experience.