How should senders log deliverability metrics?

Deliverability metric logging should capture detailed data for each send: recipient counts by provider, bounce rates and types, delivery times, open and click rates, complaint counts, and any errors encountered.

Log at granularity supporting investigation. When problems occur, you need to identify which campaigns, segments, or time periods were affected. Aggregate only logging prevents root cause analysis.

Retain logs according to business and compliance needs. Historical data supports trend analysis and investigation of delayed reported issues. Balance retention value against storage costs and privacy requirements.