Sender Score
Email MarketingAlso: Sender Reputation Score · Validity Sender Score
Quick definition
Sender Score is a reputation rating from 0 to 100 that estimates how trustworthy your sending IP address or domain looks to inbox providers. It's calculated by Validity using real complaint rates, bounce data and spam trap hits, and it's one signal mailbox providers use to decide whether your email lands in the inbox or the spam folder.
How it varies across Australia
Australian senders with clean opt-in practices and consistent sending volume tend to sit in the healthy range. Scores drop fastest after a purchased list, a long sending gap, or a sudden spike in volume. The shape to watch is the trend line, not the single-day number.
See email marketing benchmarks across Australian industries →What it actually means
Think of Sender Score as a credit rating for your email address. Mailbox providers like Gmail and Outlook don't know you personally, so they watch your behaviour over time and build a trust profile from it. Complaint rates, bounce rate, spam trap hits and sending consistency all feed into that profile.
The score itself, published by Validity, is a proxy for what the real gatekeepers (Gmail, Microsoft, Yahoo) are privately calculating. It won't match their internal number exactly, but it moves in the same direction, which makes it a useful early warning system for deliverability problems.
A score in freefall almost always traces back to one of a few causes. A purchased or scraped list. A re-engagement campaign to contacts who haven't opened in years. Sending from a new IP without proper IP warming. Missing or misconfigured authentication records like SPF, DKIM or DMARC.
The score matters less than what it's telling you. Treat it as a smoke detector, not the fire itself.
Sender Score is not a badge you earn once. It's a rolling verdict on whether the last few weeks of your sending behaviour earned trust or spent it.
How it shows up
Sender Score shows up as a slow leak before it becomes a flood. First, open rates on your usual list start drifting down for no obvious content reason. Then a handful of emails start landing in spam for specific providers, usually Gmail first. Eventually entire campaigns stop reaching the inbox for large chunks of your list, even though your sending platform reports the emails as delivered. The gap between 'delivered' and 'inbox' is where a damaged sender reputation lives, and Sender Score is one of the few tools that lets you see it before your open rate does.
The Australian context
Australia's Spam Act 2003 requires express or inferred consent before you send commercial email, along with a working unsubscribe link and accurate sender identification. Businesses that treat this as a legal checkbox rather than a deliverability strategy often end up with exactly the list hygiene problems that tank a sender score. ACMA can fine for non-compliance, but the more immediate cost is inbox providers quietly deciding you're not trustworthy and routing you to spam regardless of any formal penalty. Clean opt-in practices under the Spam Act and a healthy Sender Score are, in practice, the same discipline viewed from two angles.
Where people get this wrong
Related terms
Common questions
What's a good Sender Score?
Scores in the higher bands generally indicate healthy deliverability, while anything trending down over consecutive weeks deserves attention regardless of the absolute number. The trend matters more than the single figure, since providers watch behaviour over time, not a snapshot.
How do I check my Sender Score?
Validity, the company that calculates it, offers a free lookup tool where you enter your sending IP address. Many email service providers also surface a version of this data inside their deliverability dashboards.
Can Sender Score recover after it drops?
Yes, but it takes sustained good behaviour, not a quick fix. Clean your list, pause sending to disengaged contacts, fix authentication issues, and rebuild volume gradually. Recovery usually takes weeks of consistent, well-targeted sending.
Does Sender Score affect Gmail and Outlook the same way?
No. Each mailbox provider runs its own private reputation system and Sender Score is only a public proxy for those. A low score is a useful warning sign across all providers, but a high score doesn't guarantee equal treatment from Gmail versus Outlook.
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About New Rebellion
New Rebellion is a marketing intelligence consultancy. We build tools, score Australian businesses on how their marketing actually performs, and publish Debrief every day. This dictionary is part of how we work in the open.
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