Open Source Klaviyo Alternatives

Listmonk is a self-hosted newsletter and mailing list manager built for people who want full control over their email infrastructure. It ships as a single binary with a minimal footprint, making it practical to run on modest hardware without sacrificing throughput. If you're looking for a Mailgun alternative or a self-hosted replacement for services like Beehiiv or MailerLite, listmonk covers the full stack from campaign management to transactional messaging.

The core use case is sending large-scale email campaigns. A production instance can send 7+ million emails with CPU usage under a single core and peak RAM around 57 MB. That's genuinely lean.

Key capabilities:

• Subscriber management across single and double opt-in lists, with SQL-based querying and segmentation for precise targeting
• Multi-SMTP queues with multi-threaded, high-throughput sending and sliding window rate limiting for fine-grained control
• Transactional email API to send arbitrary messages using pre-defined templates, triggered programmatically
• Messenger interfaces extend delivery beyond email to SMS, WhatsApp, and FCM push notifications via HTTP webhooks
• Template engine with 100+ functions, logic expressions, and support for drag-and-drop, WYSIWYG, Markdown, or raw HTML composition
• Built-in analytics covering campaign performance, bounce tracking, and top link clicks
• Media library with S3-compatible backend support
• OIDC SSO authentication with granular roles, permissions, and API tokens

The backend is written in Go, the frontend in Vue, and the whole thing is licensed under AGPLv3. Compared to tools like Postal or Sendportal, listmonk stands out for its raw throughput and the breadth of its API coverage, which makes it a practical foundation for custom workflows and integrations.

Postal is a powerful, open-source mail delivery platform designed for developers and businesses who need reliable, scalable email infrastructure. With Postal, you can take full control of your email sending capabilities, whether for transactional messages or large-scale marketing campaigns.

Key benefits of Postal include:

• Self-hosted solution: Deploy Postal on your own servers, maintaining complete control over your email infrastructure and data.
• Scalability: Handle from a few emails to millions per day with ease, thanks to Postal's efficient architecture.
• Comprehensive API: Integrate Postal seamlessly into your applications with its well-documented RESTful API.
• Multiple domains: Manage and send emails from multiple domains within a single Postal instance.
• Advanced tracking: Monitor email delivery, opens, and clicks with detailed analytics and webhooks.
• SMTP support: Use Postal as an SMTP server for your existing applications or email clients.
• Suppression lists: Maintain clean sending practices with built-in suppression list management.
• Template management: Create and manage email templates directly within the Postal interface.
• Webhook integrations: Receive real-time notifications about email events for better monitoring and automation.
• Open-source flexibility: Customize and extend Postal to fit your specific needs, with the backing of an active community.

By choosing Postal, you gain a robust, cost-effective email delivery solution that puts you in the driver's seat, ensuring optimal deliverability and performance for your critical communications.

Mautic is the world's largest open source marketing automation project, empowering over 200,000 organizations to grow their communities and reach their marketing goals. With support for 35+ language translations and contributions from 1,000+ community members, Mautic offers a robust and flexible solution for businesses of all sizes.

Key features of Mautic include:

• Lead Management: Capture, organize, and nurture leads through customizable forms and landing pages.
• Email Marketing: Create and send targeted email campaigns with drag-and-drop builders and personalization options.
• Campaign Automation: Design multi-channel marketing campaigns with an intuitive visual workflow builder.
• Analytics and Reporting: Gain insights into campaign performance and lead behavior with detailed reports and dashboards.
• Integration Capabilities: Connect Mautic with popular CRM systems, social media platforms, and other marketing tools.

As an open source platform, Mautic offers unparalleled customization options and the ability to extend functionality through plugins and integrations. Whether you're a small business owner or part of a large enterprise, Mautic provides the tools you need to create engaging marketing campaigns and drive growth.

Join the Mautic community today and take control of your marketing automation with a powerful, flexible, and cost-effective solution.

Notifuse is a modern, self-hosted email platform that provides a cost-effective alternative to expensive services like Mailchimp, Brevo, and Klaviyo. Built for developers and marketers who want complete control over their email infrastructure without the recurring costs.

Key Features:

• Visual Email Builder - Create stunning emails with drag-and-drop MJML editor and real-time preview
• Contact Management - Rich profiles with custom fields and complete activity timelines
• Transactional API - Powerful REST API for automated emails with responsive templates
• Advanced Analytics - Real-time open rates, click tracking, and engagement metrics
• A/B Testing - Optimize campaigns with built-in testing for subject lines and content
• Smart Segmentation - Dynamic contact filtering by properties, activity, and behavior
• Multi-workspace Support - Perfect for agencies with isolated data and custom domains
• S3 Integration - Built-in file management with CDN delivery for images and attachments

Benefits:

• Forever Free - Open-source with unlimited subscribers and campaigns
• Self-hosted Control - Complete data ownership and privacy
• Cost Effective - No per-contact pricing or monthly fees
• Developer Friendly - Full API access and customization options
• Enterprise Ready - Team permissions, workspaces, and dedicated support available

Perfect for businesses, agencies, and developers who want professional email marketing capabilities without vendor lock-in or escalating costs.

Keila is a robust, open-source email marketing solution designed for businesses and individuals who prioritize data privacy and control. This self-hosted platform offers a comprehensive suite of features to manage your mailing lists and create engaging campaigns with ease.

Key benefits of Keila include:

• Complete data ownership: Host Keila on your own servers, ensuring full control over your subscriber data and campaign information.
• User-friendly interface: Intuitive dashboard for effortless list management, campaign creation, and performance tracking.
• Powerful segmentation: Target your audience effectively with advanced segmentation tools based on subscriber data and behavior.
• Customizable templates: Create visually appealing emails using a drag-and-drop editor or HTML for more advanced users.
• Automation workflows: Set up automated email sequences to nurture leads and engage subscribers at the right time.
• Detailed analytics: Gain insights into campaign performance with comprehensive reports on open rates, click-through rates, and more.
• API integration: Seamlessly connect Keila with your existing tools and workflows using the robust API.
• GDPR compliance: Built-in features to help you maintain compliance with data protection regulations.

By choosing Keila, you're not just getting an email marketing tool – you're investing in a privacy-first solution that grows with your needs while keeping your data secure and under your control.

Take complete control of your email marketing with this self-hosted, open-source platform that puts your data back in your hands. Built on Laravel, this modern solution offers unlimited subscribers, campaigns, and workspaces without the recurring costs of traditional services.

Key features include:

• Subscriber & List Management - Import customers via API or CSV, create custom segments
• Campaign Management - Send to all subscribers or targeted segments with beautiful templates
• Message Tracking - Automatic tracking of opens, clicks, bounces, and unsubscribes
• Multiple Workspaces - Handle different teams or projects through one interface
• Powerful REST API - Easy integration with existing systems
• Beautiful Interface - Fast, intuitive design that's enjoyable to use

Save significantly compared to MailChimp, Campaign Monitor, and other hosted services while maintaining full control over your data. The open-source nature means you can customize it to fit your exact needs, backed by the Laravel community.

Perfect for businesses wanting to reduce email marketing costs while gaining complete ownership of their subscriber data and campaigns.

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:

• Code-first approach: Write email templates as React components and define automations in TypeScript with full type safety
• Git-based workflow: Templates and workflows live in your repository - review in PRs, roll back deployments, and maintain version control
• Your infrastructure: Deploys to your AWS account using SES, DynamoDB, and your domain reputation - pay AWS directly at $0.10 per 1,000 emails
• No-code editing: Marketing teams can edit content and send emails through visual editors without filing tickets or waiting for developers
• Transparent pricing: Free to start, then pay only for platform features while AWS handles sending costs directly

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.