Notes from the deliverability lab.
How to write a cold email CTA that gets answered in 2026
The call to action is the only line that matters for reply rate after the opener. Three CTA patterns that work, three that lose, and the specific phrasing.
The InboxLee TeamMay 23How to write a cold email opener line that earns the next 30 seconds of attention
The first sentence decides whether the rest of the message gets read. Specific opener patterns that work in 2026, with the framing that beats "Hope this email finds you well."
The InboxLee TeamMay 23Cold email vs marketing email: the operational and legal differences that matter
Both arrive via SMTP, both look like email. The infrastructure, compliance, deliverability rules, and reply expectations are wildly different.
The InboxLee TeamMay 23Should you use tracking pixels in cold email? The honest cost-benefit in 2026
Apple MPP, Gmail prefetching, and modern spam filters have changed the math on email open tracking. Most cold-email teams should turn it off.
The InboxLee TeamMay 23Cold email "From" name best practices: what to use and what to avoid in 2026
The display name next to your email address is a 0.5-second trust signal. Recipients pattern-match it before they read a word of the message.
The InboxLee TeamMay 23Spamhaus SBL vs DBL: which list is which and what they each block
Spamhaus runs multiple blacklists. The SBL blocks IPs, the DBL blocks domains, and the consequences for cold email are very different.
The InboxLee TeamMay 23Gmail and Yahoo bulk-sender rules in 2026: what cold-email operators actually need to ship
Five required signals, one hard threshold at 5,000 emails per day, and a quiet penalty most senders only notice after the placement chart drops. Pulled from what we apply by default at provisioning.
The InboxLee TeamMay 22The one-click List-Unsubscribe header for cold email: what it is, how to add it, how to verify it
One header. Two lines of metadata. Gmail and Yahoo render a one-tap unsubscribe button at the top of your message. Required above 5,000 sends per day and a quiet positive signal even below.
The InboxLee TeamMay 21MTA-STS for cold email: what it is, how it interacts with TLS, and whether you need it in 2026
Optional in 2026. Not required by Gmail or Yahoo. Still a clean positive signal that inbox providers notice - and InboxLee publishes it by default.
The InboxLee TeamMay 20What actually caps your cold email reply rate in 2026
Industry "benchmarks" tend to be inflated and self-reported - ours would be too, so we are not publishing one. Here is what actually moves reply rate, and how to tell an infrastructure problem from a copy problem.
The InboxLee TeamMay 19