Here are some best practices to ensure your emails are compatible with various ESPs:
Test Across Platforms: Use tools like Litmus or Email on Acid to test how your emails render across different email clients. Use Standard HTML: Stick to basic HTML and avoid complex CSS or JavaScript, as not all email clients support advanced features. Optimize for Mobile: Ensure your emails are mobile-friendly, as a significant portion of users access emails on their mobile devices. Alt Text for Images: Always include alt text for images to ensure that your message gets across even if images do not load.