# Do I need to watch my bounce and complaint rates?

**YES**—the two numbers that matter

> Bounces under 4%, complaints under 0.08%—these two numbers are how mailbox providers grade you, and they move before your open rates do. Watch them like uptime.

"Deliverability" gets discussed like weather—mysterious, ambient, unaccountable. It isn't. Two operational metrics predict most of it, and both are on a dashboard you already have.

## The two numbers

- **Bounce rate: keep it under 4%.** Repeatedly sending to invalid addresses tells providers you don't know your own list—the signature move of a spammer with a scraped database. Bounces are also the earliest warning that your list is aging.
- **Spam complaint rate: keep it under 0.08%.** That's the healthy zone; **0.3%** is the ceiling Gmail, Yahoo, and Microsoft enforce on [bulk senders](https://doineed.email/bulk-sender-requirements) before filtering gets punitive. Complaints are recipients telling the referee, not you.

One definitional trap while we're here: **delivery is not deliverability**. "Delivered" means the receiving server accepted the message; it says nothing about inbox versus spam folder. A 99% delivery rate with mail rotting in spam is a deliverability failure your delivery metric will never show—which is exactly why you watch bounces and complaints instead.

## How to actually watch them

- **Your ESP's dashboard.** On Resend, the [Metrics tab](https://resend.com/metrics) charts bounce and complaint rates continuously, and per-email [Deliverability Insights](https://resend.com/docs/dashboard/emails/deliverability-insights) flag issues before they become patterns.
- **Webhooks for automation.** Subscribe to `email.bounced` and `email.complained` events and wire them to alerts—and to your list, so offenders are removed automatically. A [suppression list](https://doineed.email/suppression-list) does the removal part natively.
- **Gmail's blind spot.** Gmail doesn't report individual complaints back to senders, so your ESP-side complaint rate undercounts your biggest audience. [Gmail Postmaster Tools](https://doineed.email/gmail-postmaster-tools) is where Gmail shows you its number—watch both.

## When the numbers move

Rising bounces → clean the list and check what changed at the source (a stale segment? a broken signup form?). Rising complaints → your content or targeting outran consent: make [unsubscribing effortless](https://doineed.email/one-click-unsubscribe), tighten to engaged recipients, and slow down. Both respond fast if you respond fast—the expensive failures are the ones nobody was watching.

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- Canonical: https://doineed.email/bounce-and-complaint-rates
- Learn more: https://resend.com/docs/dashboard/emails/deliverability-insights
- All questions: https://doineed.email/llms.txt

An opinionated answer from the [Resend](https://resend.com) team.