Test in your ESP
Every inbox renders differently. Send tests from Mailchimp, Postmark, SendGrid, Resend or your ESP of choice and check Gmail, Outlook and Apple Mail before launch.
Responsive HTML email templates built the old-school, reliable way: nested tables, inline styles, 600 px max width, bulletproof buttons for Outlook and a dark-mode media query. Swap the copy, keep the structure.
Every inbox renders differently. Send tests from Mailchimp, Postmark, SendGrid, Resend or your ESP of choice and check Gmail, Outlook and Apple Mail before launch.
Styles are already inline where it matters. If your ESP doesn't inline the <style> block, run the file through a CSS inliner first.
Upload the files in assets/img to your ESP or CDN and replace the relative src paths with absolute URLs.
Placeholders like {{first_name}} use a neutral syntax — change them to your ESP's format (*|FNAME|*, {{ .Name }}…).