What are best practices for maintaining IP reputation?

IP reputation requires ongoing attention. These practices keep your sending infrastructure healthy:

Send only to permission-based lists: Every recipient should have explicitly opted in. No purchased lists, no scraped addresses, no assumed consent. This is the foundation of everything else.

Maintain consistent volume: Avoid dramatic spikes or long quiet periods. Predictable sending patterns build trust; erratic patterns raise suspicion.

Keep complaint rates below 0.1%: Monitor feedback loops religiously. When someone complains, suppress them immediately. Investigate spikes to find root causes.

Process bounces promptly: Remove hard bounces immediately. Monitor soft bounce patterns and suppress addresses that consistently fail.

Authenticate everything: Implement SPF, DKIM, and DMARC properly. Alignment should pass, not just the individual checks.

Monitor proactively: Check Google Postmaster Tools, Microsoft SNDS, and blocklist status regularly. Don't wait for delivery problems to investigate.

Segment by mail type: Keep transactional and marketing streams separate so problems in one don't affect the other.

Warm new IPs properly: Never blast full volume from a fresh IP. Gradual warmup builds sustainable reputation.

Reputation is earned slowly and lost quickly. Daily diligence prevents catastrophic failures.