Overview
Resend and Plunk represent two different approaches to developer email. Resend is a VC-backed startup with a polished managed service and excellent developer experience. Plunk is an open-source alternative built on AWS SES that you can self-host or use as a cloud service.
The Open-Source Advantage
Plunk's biggest differentiator is being fully open-source. You can self-host it on your own infrastructure, giving you complete data control and potentially significant cost savings at scale. Self-hosting means you only pay AWS SES costs (around $0.10 per 1,000 emails).
Pricing Comparison
Plunk's cloud service is $0.001 per email - about 5x cheaper than most competitors. Resend's Pro plan is $20/month for 50,000 emails ($0.40 per 1,000). At high volumes, Plunk is significantly cheaper. At low volumes, Resend's free tier (3,000 emails) might be enough.
Developer Experience
Resend wins on polish. The API is more refined, the SDKs are better, and React Email support is first-class. Plunk is good but simpler - it's a younger project. If developer experience is your priority, Resend is the choice.
Feature Completeness
Interestingly, Plunk includes campaigns and workflow automations, while Resend focuses on transactional with marketing in beta. If you need marketing features and want to self-host, Plunk covers more ground.
EU Data Compliance
Plunk processes data in the EU and can be self-hosted in any region. This matters for GDPR compliance. Resend doesn't currently offer EU hosting.