Deliverability Hub
Operator playbooks from an agency sending a million cold emails a month, and original research measured on live sending infrastructure. Free, no signup.
Deliverability playbooks
Operator strategies from an agency sending a million cold emails a month.
- The 2026 Inboxing Playbook — A clean operator guide for building cold email infrastructure that survives longer, routes smarter, and keeps campaigns out of spam.
- The Ultimate Liquid Syntax Guide: Hidden Ways To Personalize Cold Emails Using Your Sequencer — How to make cold emails feel timely, human, and relevant at scale with Liquid syntax, smarter conditional logic, and better sending context.
- How to Avoid the SPAM Plague in 2026: The Complete List Verification, ESP, ESG & Role Segmentation Playbook — A field-tested cold email segmentation system for cleaner lists, better inbox routing, sharper persona-based copy, and higher reply rates before you ever launch.
Deliverability studies
Original research measured on live sending infrastructure.
- Does a SURBL listing actually hurt cold email? We tested 2,817 sending domains — A DNS sweep of every live sending domain, not a sample. 43.3% were listed. Reply rate before and after listing: 1.14% to 1.16%. Own infrastructure came back 2.3x cleaner than bought-in stock.