KumoMTA
KumoMTA is an Open-Source, enterprise-grade email message transfer agent (MTA) software for sending high-volume, business-critical emails. KumoMTA is typically chosen by high-volume email users looking to replace PowerMTA, Momentum, or traditional Open Source MTAs.
KumoMTA offers high-performance message relay to the tune of millions of messages per hour per server, combined with extreme flexibility and configurability through its use of a Lua scripting engine for configuration and message management.
For more information on KumoMTA see our Sourceforge project page.
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MailerSend
MailerSend is a transactional email and SMS service designed for developers to work faster and smarter. A drag & drop builder and dynamic templates enable anyone at any skill level to create personalized transactional emails, while our SMS templates help you create professional transactional SMS messages.
MailerSend’s advanced infrastructure scales with your sendings, while the latest security protocols protect your sender reputation. Plus, you can integrate your email sending and tracking in your apps using SMTP or a flexible email API.
Built by deliverability experts, and with the inbuilt email verification tool, you can rest easy knowing your messages will be delivered and avoid spam folders, while dedicated IPs are available for high-volume senders. Plus, inbound routing enables your customers to interact with your messages, sparking conversations and increasing engagement. Get started for FREE with 500 emails, then upgrade for as little as $7/month for up to 5000 emails.
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Amazon SES
Amazon Simple Email Service (SES) is a cost-effective, flexible, and scalable email service that enables developers to send mail from within any application. You can configure Amazon SES quickly to support several email use cases, including transactional, marketing, or mass email communications. Amazon SES's flexible IP deployment and email authentication options help drive higher deliverability and protect sender reputation, while sending analytics measure the impact of each email. With Amazon SES, you can send email securely, globally, and at scale. Using either the Amazon SES console, APIs, or SMTP, you can configure email sending in minutes. Amazon SES also supports email receiving, enabling you to interact with your customers at scale. Regardless of use case or sending volume, you only pay for what you use with Amazon SES.
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SendGrid
Email is the backbone of your customer engagement. The Twilio SendGrid Email API is the email service trusted by developers and marketers for time-savings, scalability, and delivery expertise. Our flexible Email API and proprietary Mail Transfer Agent (MTA), intuitive console, powerful features, and email experts make it easy to ensure all your email gets delivered in seconds and without interruption. Monitor engagement data and optimize deliverability with our Deliverability Insights dashboard.
Whether you’re sending 100 emails or 100 billion, SendGrid is built to scale. Integrate with our RESTful APIs and SMTP in minutes, with sample code libraries available in 7 languages, interactive docs, templates, and more.
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