The best open source alternative to Hyvor Relay is Plunk. If that doesn't suit you, we've compiled a ranked list of other open source Hyvor Relay alternatives to help you find a suitable replacement. Other interesting open source alternatives to Hyvor Relay are: useSend, Sessy, and Wraps.
Hyvor Relay alternatives are mainly Email Platforms but may also be Email Marketing & Newsletter Tools or Customer Communication Platforms. Browse these if you want a narrower list of alternatives or looking for a specific functionality of Hyvor Relay.
Plunk unifies marketing, transactional, and broadcast emails into a single, complete solution for businesses of all sizes.

Plunk is revolutionizing the email marketing and communication landscape with its comprehensive, open-source platform. Here's what makes Plunk stand out:
All-in-One Solution: Plunk combines marketing, transactional, and broadcast emails in one platform, eliminating the need for multiple tools and simplifying your email strategy.
Affordable Pricing: With a cost-effective model of $0.001 per email, Plunk is up to 5 times cheaper than competitors like Mailchimp, Twilio SendGrid, and Mailgun. You only pay for what you use, not for unused contacts.
Privacy-Focused: All data is hosted, stored, and processed in the EU, adhering to strict privacy standards. Plunk prioritizes security, transparency, and data ownership.
Powerful Features:
Responsive Email Editor: Build responsive emails using Plunk's editor or import your own HTML, ensuring your emails look great even in Outlook.
Open-Source Advantage: As an open-source platform, Plunk offers transparency, customizability, and community-driven improvements.
User-Friendly: With an intuitive UI and easy setup, Plunk is accessible for businesses of all sizes and technical expertise levels.
Generous Free Tier: Send up to 3,000 emails per month for free, with no credit card required.
Plunk is trusted by over 1,000 companies, offering a blend of affordability, functionality, and privacy that makes it an attractive alternative to traditional email service providers. Whether you're sending transactional emails, marketing campaigns, or automated sequences, Plunk provides the tools and flexibility to make your email communication delightful and effective.
Open source email platform for transactional and marketing emails. Self-host or use cloud service with transparent pricing - pay only for emails sent.

Open source email platform that revolutionizes how you handle transactional and marketing emails. Unlike traditional providers, you pay only for emails sent, not for storing contacts.
Key Features:
Developer-friendly with typed SDKs for TypeScript, Python, Go, and PHP. Simple APIs let you focus on your product instead of email infrastructure.
Flexible deployment options - Self-host in minutes or use the managed cloud service. Free tier includes 3,000 emails monthly. Paid plans start at $10 with transparent per-email pricing: $0.0004 for transactional and $0.001 for marketing emails.
Built on Amazon SES for reliable delivery, useSend provides an affordable alternative to expensive email services while maintaining full control over your email infrastructure.
Track SES deliveries, bounces, opens and clicks in a self-hosted dashboard with real-time search, analytics and reputation monitoring.

Get precise visibility into every email sent through AWS SES without paying for another SaaS layer. This open-source, self-hosted dashboard captures SES events in real time so you can see what landed, what bounced, and who engaged—while keeping all data on your own infrastructure.
In short, this tool gives you real-time, self-hosted insight into every SES email, combining detailed event tracking, deliverability monitoring, and multi-project management in a single, developer-friendly dashboard.
Build email templates as React components and automations in TypeScript. Deploy to your AWS account with SES integration. Marketing teams edit content without code.

Developer-friendly email platform that deploys directly to your AWS account, giving you complete control over your email infrastructure while enabling seamless collaboration between engineering and marketing teams.
Key benefits:
Perfect for teams where developers want to maintain code quality and infrastructure control while enabling marketers to work independently. The platform bridges the gap between technical requirements and marketing needs without compromising on either side.
Open source and designed for easy migration - cancel anytime and keep your entire email infrastructure running on AWS.
Messaging Infrastructure for Developers. One API for SMS, WhatsApp, and RCS across 190+ countries.
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