MailSlurp resources
Guides - Page 2
Practical guides for MailSlurp messaging, testing, reliability, extract, account setup, and procurement workflows.
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How to Whitelist an Email in Gmail, Outlook, and Office 365
Learn how to whitelist an email in Gmail, Outlook, and Office 365, what safe-sender rules actually do, and why allowlisting does not replace sender authentication.
Read more technicalGoogle SMTP Settings: Gmail Server, Ports, Auth, and Common Failures
Use this Google SMTP settings guide to configure the Gmail SMTP server, choose the right port and TLS mode, handle app-password auth, and troubleshoot send failures quickly.
Read more technicalEmail Schema: Gmail Markup, JSON-LD, and How To Test It
Learn what email schema means, how schema.org markup works in Gmail, and how to test structured actions, auth, and delivery before launch.
Read more technicalEmail File Size Limit Guide: Attachment Caps, Gmail Limits, and Practical Sending Rules
Learn how email file size limits really work, why attachments grow during encoding, what Gmail size limits mean in practice, and how to test large-email workflows safely.
Read more technicalEmail Deliverability Best Practices for Reliable Inbox Placement
Follow practical email deliverability best practices for sender authentication, recipient quality, inbox placement, spam control, and release-safe workflow testing.
Read more technical550 Permanent Failure Blocked: What It Means for One or More Recipients and How To Fix It
Learn what `550 permanent failure blocked` and `550 permanent failure for one or more recipients` usually mean, which recipient and policy problems trigger them, and how to fix the message path without guesswork.
Read more technicalWhy Am I Not Receiving Emails? A Practical Troubleshooting Guide
Diagnose missing emails by checking spam placement, mailbox rules, sender authentication, routing, and delivery failure evidence.
Read more technicalWhat Is the Body of an Email? Structure, Purpose, and What Teams Should Test
Learn what the body of an email is, how it differs from headers, subject, and preheader, and how to write and test email body content that actually works.
Read more technicalWhat Is SSL for Email? TLS, STARTTLS, and What Email Encryption Actually Protects
Learn what people mean by SSL for email, why modern systems really use TLS, how STARTTLS differs from implicit TLS, and what email transport encryption does and does not secure.
Read more technicalWhat Is PTR? Reverse DNS, Email Sender Identity, and Why Receivers Care
Learn what a PTR record is, how reverse DNS works, and why PTR matters for email sender identity, spam filtering, and deliverability troubleshooting.
Read more technicalWhat Is BIMI? How Brand Indicators Work and What You Need Before Rollout
Learn what BIMI is, how it connects brand logos to authenticated email, which DNS and DMARC prerequisites matter, and what results to expect in real inboxes.
Read more technicalWhat Is an ESP? Email Service Provider Meaning, Types, and How To Choose One
Learn what an ESP is, the difference between marketing and transactional email providers, and how to choose a stack that covers sending, testing, and deliverability operations.
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