Learning center

Guides for people who run email infrastructure

Cold email, deliverability, DNS and the tools behind them — practical, specific, no fluff.

Why Are My Emails Going to Spam? 9 Causes and Fixes

A diagnostic checklist for emails landing in spam: authentication, reputation, list quality, content and sending patterns — with free tools to check each one.

How Many Domains Do You Need for 1,000 Mailboxes?

Planning domains, mailboxes and costs for a 1,000-mailbox cold email operation — ratios, naming, providers and how to keep it manageable.

How Many Cold Emails Can You Send Per Day?

Realistic per-mailbox and per-domain cold email limits, why provider limits are the wrong number to aim for, and how to plan volume for your team.

How to Configure SPF, DKIM and DMARC (Step-by-Step)

A practical walkthrough for setting up SPF, DKIM and DMARC on a sending domain, with exact records for Google Workspace and Microsoft 365 and the mistakes that break them.