Easily connect and send your website emails with our SMTP relay and Email API to ensure maximum deliverability, reliability, and scalability.
Need an email regex that won’t reject real customers or let typos through?
This tutorial gives you one tested pattern for JavaScript, Python, and PHP.
You’ll also learn the gotchas that let bad addresses slip through, plus MX checks, double opt-in, and SendLayer bounce webhooks.
Wondering why your mail server keeps saying “authentication required”?
Learn what SMTP authentication is and how the login exchange works, one command at a time.
This guide covers STARTTLS, the PLAIN, LOGIN, and OAuth mechanisms, Microsoft’s Basic auth retirement, and how to fix 535 and 530 errors.
Are your emails landing in spam instead of the inbox?
Learn how to check any email for free with Email Detective from SendLayer.
This guide covers sending a real test message, reading each report section, and fixing failed SPF, DKIM, DMARC, and spam checks.
Wondering why your emails keep landing in spam?
This roundup compares 10 email deliverability tools, grouped by the job each one does.
Learn which free tools to start with, what each one checks, what it costs, and when a paid tool is worth it.
