This is how programmatic outbound performs, and after Apple Mail Privacy I trust reply and meeting rates, never open rate. Reply rate is the tell for whether you are sending signal or spraying: spray gets 1–3%, personalized gets 20–40%.
Shape of it
5 signals
Share of delivered emails that get any reply.
replies / emails deliveredBenchmarkTiered by targeting (Woodpecker, 26,000 campaigns): spray 1–3%, segmented bulk 3–7%, signal-triggered 10–20%, fully personalized 20–40%. Avg cold reply is 3.43% in 2026, down from 8.5% in 2019
A reliable outbound north star where open rate is not.
Share of replies (or sends) that are genuinely interested.
Benchmark~50% of replies good; 70%+ top
Reply rate can be gamed by provocation; this measures whether messaging resonates.
Share of sent emails that convert to a booked meeting.
meetings booked / emails sentBenchmark~1% average; 3.5%+ top
The closest outbound metric to pipeline; the real denominator for cost.
Share of sent emails rejected by the receiving server.
bounces / emails sentBenchmarkKeep under 2%
High bounce rate destroys sender reputation fast; the leading hygiene indicator.
Share of delivered emails marked as spam.
spam complaints / emails deliveredBenchmarkMust stay below 0.30% (Google/Yahoo, Feb 2024); target under 0.10%
The single hardest line in outbound. Cross it and your mail gets throttled or blocked.