About SendLens

We built SendLens because we needed it.

Retention Machine runs Klaviyo for a roster of e-commerce brands. As we scaled past ten clients we hit a wall. There was no good way to see how all the brands were doing in one place. So we built one. Other agencies asked to use it. That's how SendLens became a product.

How we got here.

01Early days

Juggling Klaviyo accounts

Managing ten-plus Klaviyo accounts meant endless tab-switching, spreadsheet snapshots, and no unified view of how clients were performing. We spent more time wrestling with data than improving campaigns.

02The build

We built it for ourselves first

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.

03Opening up

Other agencies asked to use it

It worked so well that other Klaviyo 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.

What we built

Everything we needed to run our agency. Built into one place.

Every feature comes from a real problem we hit while managing clients. Not a roadmap dreamed up in a vacuum.

Multi-brand dashboards

Campaign and flow performance across every client on one screen. Compare brands, spot trends early, find your strongest plays.

AI insights + Ask SendLens

Subject line patterns, send-time windows, and anomaly alerts built from your data. Plus an in-app chat that reads from your reports and connects to Klaviyo live.

Read by default, write on approval

Analytics use a read-only Klaviyo key. Anything that writes (drafting a segment, drafting a campaign) surfaces a confirmation card you have to approve first.

Made by Retention Machine

Built by the agency using it every day.

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, auditing accounts, and chasing revenue.

The multi-brand dashboard exists because we were sick of logging into ten Klaviyo accounts. The weekly briefings exist because clients kept asking for the same data in the same format every Monday. The lifecycle audit exists because pitching new business took too long without one. Ask SendLens exists because we wanted to query our own data without leaving the dashboard.

When you use SendLens, you're using the same tool we use internally. We're not building features in a vacuum. We're solving our own problems and sharing the solution.

Get in touch or see what we run for clients.

Why teams choose us

Three reasons agencies stick around.

Your data stays yours

Klaviyo keys are encrypted at rest. Analytics run on a read-only key. No third-party data sharing. Revoke access whenever you want.

Agency-tested

We use SendLens every day at Retention Machine. Features come from real problems we run into managing clients. If you ask for one, there's a good chance we've already wanted it ourselves.

Klaviyo-focused

SendLens is purpose-built for Klaviyo. Deep integration, fast syncs, and metrics that actually matter for retention marketing. No generic email-marketing fluff.

Get started

Try it for 7 days. See your Monday change.

See how much time you save when every Klaviyo account on your roster lives in one dashboard.