new sending domain, how long before it's safe to send cold email from it?
Went through this when setting up a fresh domain for cold outreach and the online consensus is all over the place, so sharing what came out in decent shape.
DNS setup has to come first before the warmup starts (SPF, DKIM, and DMARC all verified through something like MXToolbox), because a broken DMARC at warmup start means the entire ramp period builds reputation on a misconfigured foundation and you won't catch it until real sends start failing.
For the warmup itself, I ran it through an automated tool (Lemwarm by Lemlist specifically), which pulls a real inbox network together where sends go out and replies come back so the activity pattern looks like two-way human traffic to ESPs , which one-directional sends don't.
And the timeline that held for us was around 4 weeks before touching real prospects, though the cleaner signal to watch is domain reputation in Google Postmaster Tools leveling off , the date barely matters.
The common mistake on new domains is either skipping DNS setup entirely or jumping to full cold volume right after warmup instead of starting at maybe 20 sends a day and building from there.