Built by email marketers
Retention Machine is an email marketing agency that manages Klaviyo for e-commerce brands. As we scaled to more clients, we hit a wall. There was no good way to see how all our brands were performing in one place. We were logging into each Klaviyo account one by one, pulling numbers into spreadsheets, and spending hours on reporting that should have taken minutes.
Early days
Managing multiple Klaviyo accounts meant endless tab-switching, manual spreadsheet updates, and no unified view of how our clients were performing. We spent more time wrestling with data than actually improving campaigns.
The build
So we built an internal tool. One dashboard to track campaigns, flows, deliverability, and revenue across every client. No more logging in and out of accounts. No more copy-pasting into Google Sheets. Just the metrics that mattered, all in one place.
Opening up
It worked so well for our team that other agencies and brands started asking if they could use it too. That's when SendLens became a product. If you run email for more than one brand, you know the pain. This is the tool we wish existed when we started.
Everything we needed to run our agency, built into one platform.
See campaign and flow performance across all your brands in one place. Track revenue, open rates, click rates, and deliverability side-by-side. Compare brands, spot trends early, and identify your best-performing strategies at a glance.
Get recommendations on subject lines, send times, and strategy based on your actual data, not generic best practices. Built to help you improve, not just report.
We use read-only Klaviyo API keys. We can't touch your accounts, send emails, or modify anything. Your data is encrypted and never shared with anyone.
Made by Retention Machine
Retention Machine is an email marketing agency focused on e-commerce brands. We manage Klaviyo for clients selling everything from supplements to fashion to home goods. We live in Klaviyo every single day: writing campaigns, building flows, analysing performance, and optimising for revenue.
SendLens exists because we needed it. Every feature comes from a real problem we hit while managing clients. The multi-brand dashboard? We were tired of logging into 10+ Klaviyo accounts. The AI insights? We wanted to spot patterns across brands faster. The reports? Clients kept asking for the same data in the same format.
When you use SendLens, you're using the same tool we use internally at Retention Machine. We're not building features in a vacuum. We're solving our own problems and sharing the solution.
Get in touch →Everything is encrypted and we never share your data with anyone. Read-only Klaviyo access means we can't touch your accounts. Your API keys are stored securely and can be revoked at any time. No data sharing with third parties.
We use SendLens every day at Retention Machine. Features come from real problems we run into managing clients, not a product roadmap dreamed up in a vacuum. When you request a feature, there's a good chance we've already thought about it.
We don't try to be everything for everyone. SendLens is purpose-built for Klaviyo users and it shows in every detail. Deep integration, fast syncs, and metrics that actually matter for email marketing.