Blog

September 2, 2026 Domain Rotation for Cold Email: How It Works and When to Use It What domain rotation actually protects you from, how to structure a domain fleet, when rotation helps and when it is a workaround for a problem you should fix instead. Read article → September 1, 2026 MX Records for Multi-Domain Cold Email: Setup and Common Mistakes How MX records work across a fleet of sending domains, why replies get lost when they are wrong, and the setup mistakes that quietly cost you meetings. Read article → August 31, 2026 Cold Email Ramp Schedule: How Fast You Can Safely Increase Volume A week-by-week schedule for ramping new domains and mailboxes, the metrics that tell you to slow down, and how to recover when you have pushed too hard. Read article → August 28, 2026 How Many Mailboxes Do You Need for Cold Email? (With the Actual Math) Work out how many mailboxes and domains your sending volume requires, why the safe per-mailbox limit is lower than the technical one, and how much headroom to buy. Read article → August 27, 2026 Bulk DNS Updates for Cold Email: How to Manage 50+ Domains Safely Managing SPF, DKIM and DMARC across dozens of sending domains by hand is where silent deliverability failures come from. Here is a safe process, and how to automate it away. Read article → August 26, 2026 SMTP Relay vs SMTP Server: Which One Cold Email Actually Needs The difference between an SMTP relay and your own SMTP server, what each does to deliverability and control, and which one makes sense at your sending volume. Read article → August 25, 2026 SMTP Error Codes Explained: 550 5.7.1 and the Ones That Actually Matter A practical guide to the SMTP errors cold email senders hit most, what each one is really telling you, and the fix for each, including 550 5.7.1, 5.7.26, 421 throttling and soft bounces. Read article → August 24, 2026 Google Bulk Sender Guidelines in 2026: What Changed and How to Comply Google now rejects non-compliant bulk mail outright instead of filtering it. Here are the current SPF, DKIM, DMARC, spam-rate and one-click unsubscribe requirements, who they apply to, and how to check you pass. Read article → August 12, 2026 Google Workspace Cold Email Cost: The Real Math Per Mailbox What Google Workspace mailboxes actually cost for cold email once you account for resellers, mailbox count, domains and DNS, and the volume at which per-seat pricing stops making sense. Read article → August 10, 2026 Dedicated IP for Cold Email: What It Costs and When It’s Worth It A practical guide to dedicated IPs for cold outreach: what shared IPs actually cost you, the volume where a dedicated IP starts paying off, how to warm one, and what providers charge. Read article →