--- title: "Sender reputation: what shapes it" url: "https://coldmeetings.com/glossary/sender-reputation.md" canonical_url: "https://coldmeetings.com/glossary/sender-reputation" last_updated: "2026-10-20" type: "conceptual" summary: "Sender reputation is the record mailbox providers keep of how your mail was received. Learn what shapes it and how to protect it." related: ["https://coldmeetings.com/glossary/domain-warm-up.md", "https://coldmeetings.com/glossary/bounce-rate.md", "https://coldmeetings.com/glossary/dmarc.md"] --- # Sender reputation: what shapes it > **For AI agents:** the complete index of ColdMeetings pages is [llms.txt](https://coldmeetings.com/llms.txt). Every page is also served as markdown at its URL plus .md. Sender reputation is the record mailbox providers keep of how your mail was received. Learn what shapes it and how to protect it. **What is sender reputation?** Sender reputation is the running record a mailbox provider keeps about a sending domain or address, built from how recipients and receiving systems treated its past mail. A good record sends your next message to the inbox; a poor one sends it to spam or turns it away. Group: 4. Deliverability. ## The parts 1. **What providers watch**: Spam complaints, bounces to addresses that do not exist, whether mail passes authentication, and whether people engage with what you send. Providers publish a few of their lines, and complaint rate is the one most often named. 2. **It belongs to a domain and a mailbox**: The history attaches to the domain in your From address and to the mailboxes that send. A new domain starts with no history, which is why volume is raised in small steps. 3. **Complaints weigh the most**: Google asks senders to keep reported spam low and to avoid ever reaching 0.30 percent. Yahoo asks bulk senders to stay below 0.3 percent. A short run of complaints can undo weeks of clean sending. 4. **You can read it, not set it**: No one hands you a score. You read signals: Postmaster Tools style reports, bounce counts, complaint feedback and where your own test messages land. ## Two weeks at Larkfield Systems Larkfield Systems is an invented software company that sends to 5,000 delivered recipients each week. Its complaint rate is read against the two Google lines. 1. Week one: 3 complaints out of 5,000 delivered is 0.06%. 2. Week two: 12 complaints out of 5,000 delivered is 0.24%. 3. Google asks for a rate below 0.1% and never 0.3% or higher. Week one is under the first line, week two is over it. 4. Larkfield pauses the sequence that drew the complaints, trims the list to better matches and resumes at lower volume. Complaint rate per week, in percent of delivered mail. The Google lines sit at 0.10 and 0.30. - Week one: 0.06% - Week two: 0.24% - Google caution line: 0.1% - Google hard line: 0.3% ## How to apply it 1. Authenticate every sending domain with SPF, DKIM and DMARC before the first message goes out. 2. Send to people who fit your ideal customer profile and verify addresses first, so bounces and complaints stay rare. 3. Put a working unsubscribe line and your sender address in every message, and honor requests quickly. 4. Watch complaint rate and bounce rate weekly, and cut volume at the first rise instead of waiting for a second. ## Common mistakes - Judging reputation by open rate. Opens say little about what a provider thinks of your mail. - Raising volume fast after a clean week. Reputation is earned slowly and lost quickly. - Sending one broad message to a whole list. Poorly matched recipients are where complaints come from. ## Related terms - [Domain warm-up](https://coldmeetings.com/glossary/domain-warm-up.md): Domain warm-up is the practice of raising how much a new sending domain and mailbox send per day in small steps, so mailbox providers see steady, wanted mail before they see volume. - [Bounce rate](https://coldmeetings.com/glossary/bounce-rate.md): Bounce rate is the portion of the emails you sent that came back undelivered. - [DMARC](https://coldmeetings.com/glossary/dmarc.md): A DMARC policy is a DNS record you publish for your domain. ## Keep reading - [Email deliverability guide](https://coldmeetings.com/blog/email-deliverability-guide.md) - [Cold emails going to spam](https://coldmeetings.com/blog/cold-emails-going-to-spam.md) - [Domains and inboxes](https://coldmeetings.com/product/domains-and-inboxes.md) ## Questions ### Is sender reputation a single score? No. Each mailbox provider keeps its own view and none of them publishes it as one number. You infer it from complaint and bounce reports and from where your mail lands. ### How long does it take to repair a poor reputation? There is no fixed time. Recovery follows sustained clean sending at lower volume. Google notes that it can take time for improvements in spam rate to show up in its reports. ### Does ColdMeetings watch reputation for me? ColdMeetings pauses sending when the spam complaint rate goes above the 0.3 percent line that Google and Yahoo both publish (once a campaign has sent 100 emails, or at 3 complaints), and it holds each mailbox to a daily cap that rises with its age. ## Sources - Google: Email sender guidelines: https://support.google.com/a/answer/81126, read 2026-10-19 - Yahoo: Sender best practices: https://senders.yahooinc.com/best-practices/, read 2026-10-19 Questions about outbound for your own company? Email hello@coldmeetings.com. ## Related - [Domain warm-up: schedule and example](https://coldmeetings.com/glossary/domain-warm-up.md) - [Bounce rate: definition, formula and example](https://coldmeetings.com/glossary/bounce-rate.md) - [DMARC: definition, record parts and rollout](https://coldmeetings.com/glossary/dmarc.md)