How I Built a Free Inbox Placement Test with Node.js and SSE

The Problem I've been doing B2B cold outreach for 5+ years. The #1 blind spot? ESPs confirm SMTP delivery — status 250, "message accepted." But they never tell you which folder your email actually landed in. Your campaign could have a 0% open rate not because of bad copy, but because every email is sitting in Spam. And you'd never know. The Solution I built a free tool that answers one question: did my email hit Inbox, Spam, or Promotions? Try it here: https://check.live-direct-marketing.online/