Writing about deliverability, agency operations, the warmup pool architecture, and what we ship every week. Built by the team that runs NuMail.
Most warmup pools are a single graph: every mailbox cross-sends with every other mailbox. That works until one new sender starts spam-trapping you. We built ours with Bronze / Silver / Gold reputation tiers and an opt-in pairing matrix. Here's the full architecture, and the three quarantine triggers that decide who stays out.
Once a week, on Tuesday. Written by the people building the platform. No third-party newsletters, no growth-hack threads.