Notes from the deliverability lab.
Domain age and cold email: how new is too new
Aged domains help. Brand-new domains hurt. The transition between the two is sharper than most operators expect.
The InboxLee TeamApr 2Reading Gmail Postmaster Tools as a cold-email operator
Postmaster Tools is the only direct signal Gmail gives you. Here is how to actually use it without panicking at the first red bar.
The InboxLee TeamApr 1Inbox placement vs delivery rate: stop optimising the wrong number
Delivery rate is a fictional metric. Inbox placement is the only one that matters. Here is the difference and why it costs operators their pipeline.
The InboxLee TeamMar 29MX records and cold email deliverability: the often-forgotten record
SPF, DKIM, DMARC get all the attention. MX is the one that controls what happens to bounces and replies - and it matters more than people think.
The InboxLee TeamMar 26The 1-record rule: why your domain can only have one SPF
The single most common cold-email deliverability bug: two SPF records on the same domain. Here is why it breaks SPF entirely.
The InboxLee TeamMar 22Soft bounces vs hard bounces: how each one hurts your sender reputation
Both are bad. They hurt in different ways, and the response strategy is different for each.
The InboxLee TeamMar 19Seed list testing for cold email: how to actually measure inbox placement
Seed lists are the only way to measure inbox placement directly. Here is how to build one that returns real signal.
The InboxLee TeamMar 15How many mailboxes do you actually need for cold email?
A simple formula based on daily send volume, ramp time, and the 50-per-day Gmail ceiling.
The InboxLee TeamMar 12.com vs .co vs .io: which TLD lands best for cold email
TLD choice is a deliverability signal, a cost signal, and a brand signal. The right pick depends on which you optimise for.
The InboxLee TeamMar 10DNS propagation timelines: when "live" is actually live
Propagation is not instant. Here is how long each step takes and what to expect during the wait.
The InboxLee TeamMar 7