Bounces do not get you blocked, complaints do
Both numbers are expressed as a percentage of a list, both are used to judge a sender, and they are produced by completely different events. A bounce is a machine answering that a mailbox cannot receive your mail. A complaint is a person pressing a button that says your mail was unwanted. Only one of them is fixable by verifying addresses.
Two metrics, two mechanisms
| Bounce rate | Complaint rate | |
|---|---|---|
| Who produces it | The receiving server, automatically | The recipient, deliberately |
| What it is about | Your list data - the address stopped working | Your message - the person did not want it |
| What lowers it | Fresh data and a probe at send time | Relevance, consent, and frequency |
| Can verification fix it | Yes - it is the whole point of probing | No - a verified address can still complain |
| Typical published guidance | 2-5% for checked contacts against 10-35% for static resold databases | Gmail: keep below 0.10%, never reach 0.30% or higher |
Complaint figures: Gmail's email sender guidelines require bulk senders to keep the user-reported spam rate in Postmaster Tools below 0.10% and to prevent it from reaching 0.30% or higher; since June 2024 senders above 0.30% are ineligible for mitigation, and eligibility returns after seven consecutive days below that line (support.google.com/mail/answer/81126, support.google.com/mail/answer/14229414).
Why the numbers are not comparable
- The scale differs by two orders of magnitude. A list with 4% bounces is ordinary and fixable. A complaint rate of 0.3% is a deliverability incident. Reading one as if it were the other is how a team ends up relaxed about the wrong metric.
- The denominators differ. Bounces are counted against your send volume; complaints are counted against mail that reached the inbox, which means the rate rises when your mail gets through, not when it fails.
- Bounces are data decay. 23% of contacts change jobs annually (ZoomInfo 2025) and 40% of email addresses are dead within two years (NeverBounce), so some bounce volume is guaranteed even with a perfect list. Complaints are not decay - a person who marked you as spam yesterday does not become a fan today.
- Complaints are about relevance, and relevance is not a list problem. 42% of B2B data goes stale within a year (Harvard Business Review, 2024), but no amount of freshness stops an unwanted send to a live, verified address.
What verification actually buys you here
It removes the noise that makes the second number hard to read. A list full of dead addresses produces bounces and zero engagement, and dead rows are exactly where an unwanted send is cheapest to make and hardest to notice: nobody complains about mail they never received, and nobody replies to it either. Clearing the dead rows means the addresses you do send to are the ones that can respond, so the signal you get back is about your message rather than about your data.
- Probe at send time, not on a schedule. Deliverable is a statement about now, with a date on it.
- Do not treat a verified address as consent. The three states are deliverable, undeliverable, or
unknownfor catch-all domains - existence, never interest. - Keep one-click unsubscribe and honour it fast. Gmail's guidelines make it a requirement for bulk senders, and a complaint is what someone does when unsubscribing is harder.
- Watch both numbers on separate dashboards. Postmaster Tools reports spam rate and reputation for Gmail recipients; your own pipeline reports bounces. Neither replaces the other.
- Send less when the complaint rate rises. Complaint rates carry a feedback delay - Google documents up to seven days for recovery after fixes - and more volume during a spike makes the hole deeper.
What TAPAC returns
npx -y @tapacapi/mcp # tools: tapac_find_contacts, tapac_status # or hosted: https://tapacapi.com/mcp # or REST: POST https://tapacapi.com/v1/contacts/search
Each contact carries a state - deliverable, undeliverable, or unknown - plus the time of the probe and the source page or profile the address came from. That is what makes a bounce rate a number you can act on: checked contacts carry a published 2-5% bounce rate against 10-35% for static, resold databases, on pay-per-use pricing of $0.10-0.50 per contact with 100 free searches. For complaint rate there is no equivalent shortcut, which is the point: verification fixes the list, and only relevance fixes the complaints.
Related: hard versus soft bounces, the cold email bounce rate, and what an accuracy claim is measured against.
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