If your Klaviyo emails don’t reach the inbox, they have no chance of generating revenue. Deliverability is the foundation of successful email marketing, with spam placement, poor sending practices and technical issues all impacting performance. Recovering from deliverability problems can be difficult but here we cover the fundamentals, common pitfalls and ways to improve inbox placement.
The short answer is it could be for many reasons. The good news is we’ll cover all the core areas on this page and walk you through it.
Areas range from missing domain authentication and poor list hygiene through to weak engagement signals, aggressive sending and even low quality data capture.
Inbox providers now assess far more than just the email itself. They analyse sender reputation, user behaviour, complaint rates, consistency, engagement and technical trust signals before deciding where your emails belong.
We’d hope you have heard of this when setting up your account but email authentication helps mailbox providers verify you emails. This is really important as without this validation, inbox provider may think you are impersonating a brand or worse, a malicious sender.
This is achieved by properly configuring SPF, DKIM and DMARC records improve trust, strengthen domain reputation and increase the likelihood of landing in the inbox rather than spam.
Within Klaviyo, this is typically achieved by authenticating a dedicated sending domain through your DNS provider, where Klaviyo supplies the required records to add.
Once configured correctly, authentication becomes one of the foundational building blocks of long-term email deliverability and sender trust.
A good way to look at domain reputation is very much like your email sending credit score. Mailbox providers such as Outlook or Gmail build trust in your domain (or not) over time based on engagement.
In addition to the positive metrics, they will also look at things like complaint rates – when grouped together with sending consistency, list quality and authentication – if can paint a picture of your score and likelihood of being sent to inbox. Even well designed Klaviyo campaigns can struggle to reach the inbox if your domain reputation is weak.
Recovering reputation can take time, particularly after aggressive sending, poor-quality data collection or repeatedly emailing disengaged audiences. If you are suffering symptoms of low domain reputation – recovery can be dynamic and this is where we’d recommend a Klaviyo expert / speaking to us about our Klaviyo agency services.
Something to consider, an email in Klaviyo marked as “delivered” does not necessarily mean it reached the primary inbox.
Modern mailbox providers sort emails into Primary, Promotions, Updates, Spam and other filtered tabs based on sender trust, engagement history and content quality.
Strong inbox placement is achieved through a combination of healthy domain reputation, proper authentication, engaged audiences and consistent sending behaviour.
If you start and see a quite sudden decline around open rates or perhaps campaign starting to underperform – this is often one of the first areas worth investigation around inbox placement.
We’ve looked at a few things that could be going wrong, let’s look at something you can do to help improve your send-ability – which is engagement based sending.
Mailbox providers pay close attention to how recipients interact with your emails. If large portions of your audience stop opening, clicking, replying or regularly engaging with campaigns, it sends negative quality signals that can damage deliverability over time.
Engagement-based sending focuses on prioritising active subscribers, gradually reducing sends to disengaged users and building automations around customer behaviour rather than mass broadcasting.
Within Klaviyo, segmentation makes this far easier, allowing brands to tailor frequency, suppress inactive profiles and protect overall sender reputation while improving campaign performance.
Poor-quality data is one of the fastest ways to damage Klaviyo deliverability.
Purchased lists (please don’t), invalid email addresses, disengaged contacts and weak data collection methods can all increase bounce rates and spam complaints.
You have to play additional attention to maintaining a healthy database – there aren’t any shortcuts you can take here, especially when you are looking at longevity and sustainable growth.
Until you have confidence in the strategy, this next line may feel like you’re missing out on sales. Not every profile should continue receiving emails indefinitely.
A strong suppression strategy prevents repeated sending to inactive, bounced or unengaged contacts that negatively impact deliverability over time. As we mentioned – confidence needs to be built that the people we aren’t emailing likely weren’t going to engage with the brand – this is where our expertise can really help.
Klaviyo allows brands to suppress risky or low-quality profiles, helping maintain healthier engagement signals and stronger inbox placement. Who not to email is equally as important against who to email.
Consent and transparency play an important role in long-term deliverability. Mailbox providers increasingly assess behavioural trust signals alongside technical setup, making genuine opt-ins and clear acquisition methods more important than ever.
The hard and fast rule is true Klaviyo growth comes from building engaged audiences who actively want to hear from you. You have their positive opt in and you aren’t taking liberties with your sending; short term strategies often lead to longer term growth suppression.
Have a quick peek at some of the results we've delivered for our email/Klaviyo clients.
From Klaviyo compliance through to list cleaning, there isn't much we haven't done - we'd always recommend getting in touch but equally, here are a few questions we get asked a lot.
We work with brands that turnover thousands to over £10bn – there isn’t much we haven’t seen. Paddy who heads up our Klaviyo function has over 10 years industry experience too – between our team, there isn’t much we can’t help with – let’s get a conversation going and see if we can help grow your inbox deliverability but also your Klaviyo revenue.
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