Deliverability
Email MarketingAlso: Email Deliverability · Inbox Placement
Quick definition
Deliverability is the ability of your emails to reach the intended inbox rather than the spam or junk folder. It depends on your sender reputation, list quality, authentication records and engagement history. An email can be sent successfully and still fail to be delivered.
How it varies across Australia
Most Australian businesses sending commercial email don't actively monitor inbox placement. Deliverability issues tend to surface only after something visibly breaks, at which point sender reputation has already taken a hit. Businesses with strong list hygiene and authentication in place consistently outperform those relying on default ESP settings.
See email marketing performance across Australian industries →The three authentication records that matter
A DNS record that lists which servers are authorised to send email on behalf of your domain.
Required: tells receiving servers your email is legitimateA cryptographic signature added to outgoing email that lets receiving servers verify the message wasn't altered in transit.
Required: proves message integrityA policy that tells receiving servers what to do when an email fails SPF or DKIM, and where to send reports.
Recommended: controls and reports on failuresWhat it actually means
Deliverability is the gap between 'sent' and 'received.' Your email platform will report a send rate close to a hundred percent almost always. What it won't tell you is how many of those landed in spam, in a promotions tab, or in a folder your recipient never opens.
Inbox placement is decided by a combination of technical signals and behavioural signals. The technical side is authentication: Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM) and Domain-based Message Authentication, Reporting and Conformance (DMARC) records tell receiving mail servers that you are who you say you are. Skip these and your email arrives like a car with no plates.
The behavioural side is harder to fix once it breaks. Spam complaint rates, bounce rates, unsubscribe rates and engagement history all feed into your sender reputation, a score that inbox providers like Google and Microsoft maintain quietly and share with nobody. A reputation that degrades over time is slow to rebuild.
For most Australian businesses, deliverability issues are invisible until they're serious. By the time a campaign lands in spam at scale, the underlying signals have usually been declining for months.
You can send a hundred thousand emails and have zero of them matter if they never reach the inbox.
How it shows up
Deliverability issues show up in a few different places. Open rates that drop over weeks without an obvious cause often signal inbox placement problems rather than content problems. Postmaster Tools (available for Google Workspace domains) and Microsoft's SNDS give direct visibility into how your domain is being treated by their infrastructure.
Your email service provider's bounce report distinguishes between hard bounces (permanent failures) and soft bounces (temporary). A rising hard bounce rate signals list quality problems. A rising spam complaint rate signals audience-fit problems or overly frequent sends. Both feed back into sender reputation and, from there, into where your future emails land.
The Australian context
Australia's Spam Act 2003 sets a clear legal standard: commercial email requires consent, a working unsubscribe mechanism, and sender identification. Non-compliance isn't just a deliverability risk, it's a regulatory one enforced by the Australian Communications and Media Authority (ACMA). ACMA has issued substantial fines against Australian companies for consent failures that were also deliverability failures.
The practical implication is that Australian marketers need to treat consent management as infrastructure, not just compliance. A permission-based list built under the Spam Act tends to perform better on deliverability metrics anyway, because it's an inherently more engaged audience.
Where people get this wrong
Related terms
Common questions
How do I know if my emails are landing in spam?
Check Google Postmaster Tools if you send significant volume to Gmail addresses. For Microsoft, SNDS provides similar signals. Seed testing tools let you send to test inboxes across providers and see exactly where you land. A sustained drop in open rates with no obvious cause is often the first signal something is wrong.
Do I need SPF, DKIM and DMARC if I use a reputable email platform?
Yes. Most email service providers send on your behalf using your domain. Without authentication records pointing to them, receiving mail servers have no way to verify the email is legitimate. Your ESP handles the sending infrastructure. The DNS records are your responsibility.
Can I recover from a damaged sender reputation?
Yes, but it takes time. Clean your list, pause high-volume sends, fix authentication, and rebuild by sending to your most engaged segment first. Gradually increase volume over weeks. Reputation recovery is measured in months, not days.
How does the Australian Spam Act affect deliverability?
The Spam Act 2003 requires consent, identification and an unsubscribe mechanism for commercial emails sent from Australia. Contacts acquired without proper consent tend to disengage or complain at higher rates, both of which damage deliverability. Compliance and good inbox placement are aligned goals.
Keep exploring
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.
How we think →