Email deliverability, decoded.
Field notes, benchmarks, and practical guides on getting your email into the inbox, from authentication and reputation to content and the filters that decide it all.
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SPF include: Over 10 Lookups Does Not Fail Every Message The SPF include mechanism and the ten DNS lookup limit: which terms cost a lookup, why the count is higher than it looks, and who actually fails. Email Authentication Explained: SPF, DKIM, DMARC and BIMI Email authentication is three DNS records. What SPF, DKIM and DMARC each prove, why alignment is where they fail, and what mailbox providers now require. Best DMARC Monitoring Tools, Measured From 166 Live Records Which DMARC monitoring tools 166 major domains actually use, the five things vendors call free, and why a third reporting address may receive nothing. RFC 9989: DMARC Deleted Three Tags and 46% Still Publish One RFC 9989 removed pct, ri and rf from DMARC in May 2026. What each deletion changes, which one made live records stricter, and how to read yours. Email Testing MCP Servers: Only 3 of 107 Test Placement Most email MCP servers send mail or hand an agent a mailbox. Of the 107 in the official registry, three test where a message actually lands. Google Postmaster Tools v2: What Changed and What It Misses The old interface is being switched off, and Domain Reputation with it. What the six v2 dashboards measure, what replaces reputation, and the metric that lies. Email Deliverability Statistics (2026): What Our Data Actually Shows 2026 email deliverability statistics from millions of daily tests: 63% inbox rate, 33% spam, plus provider, authentication, and industry benchmarks. Best Transactional Email Services in 2026, Prices Verified Ten transactional email services compared on deliverability architecture and cost, with every price read from the vendor’s own page in August 2026. How to Send a Test Email in Klaviyo (and What It Will Not Tell You) The exact click path for a Klaviyo test send, the 30-recipient cap, the monthly quota, everything Preview & test strips out, and when you need a real send. How to Send a Test Email in SendGrid (and Read the Result Right) The click path for a SendGrid test send, why it rewrites your subject line, how Spam Test and Inbox Rendering Test differ, and what Email Testing credits cost. How to Send a Test Email in Mailchimp (and What Each One Costs) The click path for a Mailchimp test email, why every test burns a send credit, the From address the template builder substitutes, and what Inbox Preview costs. How to Send a Test Email in Salesforce Marketing Cloud The Content Builder test send path, the five-address cap, the [Test]: subject qualifier, and why every Marketing Cloud test bills against your send threshold.
