Engineering & Product Blog
In-depth technical tutorials, deliverability architectures, and best practices from the Mailofly team.
SMTP Port 587 vs. 465 vs. 25: Which Port Should You Use in 2026?
A clear breakdown of SMTP ports 587, 465, 25, and 2525. Learn the difference between STARTTLS and implicit SSL, why port 25 is blocked, and how to choose the right port.
Mailofly Team
7 Best Free Email APIs in 2026 for Developers
Looking for a free email API for your app or SaaS? We compare 7 popular email APIs, including Mailofly, Resend, Brevo, Mailgun, Mailjet, Postmark, and Amazon SES — covering free limits, API and SMTP support, key features, and which type of project each one is best suited for.
Mailofly Team
The Unseen Engineering Behind Every Successful Email Send
Email deliverability isn't a given; it's a constant, engineered effort. Behind every successful send lies robust infrastructure, meticulous IP reputation management, and real-time monitoring.
Mailofly Team
Mastering Email Deliverability: Ensuring Your Messages Land Where They Matter
Email deliverability is crucial for every business, yet often misunderstood. Learn how to ensure your important messages consistently reach the inbox, not the spam folder, and why it's non-negotiable for your success.
Mailofly Team
Difference Between Transactional Emails and Marketing Emails
Learn the difference between transactional emails and marketing emails, including their purpose, examples, open rates, and why businesses need both for a successful email strategy.
Mailofly Team