If you bring a dedicated IP, warm it carefully. Cold IPs that suddenly send high volume trigger every anti-spam heuristic.
The schedule we recommend: Day 1, 50 sends. Day 2, 100. Double daily through day 7, then increase 50% daily until you reach target volume. Most warmups take 14-30 days.
The audience matters. Start with your most-engaged subscribers. Their opens and clicks signal to mailbox providers that your IP is legitimate. Save unengaged segments for the end of warmup.
Watch postmaster scores daily. Gmail Postmaster Tools, Microsoft SNDS. If reputation dips, pause and investigate before continuing.
Inbox OSS automates this. When you add a dedicated IP on Pro or Enterprise, we apply the schedule and ramp adjustments automatically. You just send.