Software · in build · early access in 2027
Your agency sends on its calendar. Your customers buy on theirs.
I’m building software that does the work brands pay a retention agency for, on their own Klaviyo account. It finds when your customers actually come back, builds the program around that clock, writes in your brand’s own words, and measures every change against a holdout set before launch. Nothing reaches a customer until a named person on your team approves the exact words.
Why software
An agency sells hours. The work doesn’t fit in them.
A retention program is a steady stream of small decisions: when each customer is due, what they bought, what the last email said, what the test shows. An agency has to ration those decisions into the hours on the invoice, so the program runs on a content calendar and the report runs on the platform’s attribution. Some agencies do the work well. The model makes it hard at any price.
An agency plans sends on a content calendar. The software finds each customer’s own clock in your orders, the days between a first order and a second, and builds the program to fire on it.
An agency drafts through whoever is on your account this quarter. The software drafts from your own pages and your founder’s own words, and every figure or claim has to trace to something you published, or the draft fails.
An agency reports what the platform credits to email. The software sets a holdout before launch and reports the difference between the groups, with the platform’s number beside it, labeled as that.
An agency checks what a person has time to check. The software renders every email on a phone, in Gmail, in Outlook and in dark mode, keeps it under Gmail’s clipping size, and reads every link and audience back from your account before anything is scheduled.
An agency works in your account under its own process. The software puts drafts in your Klaviyo, and nothing is scheduled until a named person approves the exact words. Change a word and the approval is void.
It never sends on its own
A draft, then a named approval of those exact words, then a schedule. There is no button that skips the approval.
No hidden-text tricks
Nothing that hides text to game the inbox tabs. Sending platforms suspend accounts for it, and it isn’t how you earn the inbox.
Your customers stay out of the model
The writing model sees your public pages and the brief. Not your customers’ names, emails or order histories.
The least access that works
Only the Klaviyo permissions each step needs, and your key is never stored in plain text or written to a log.
Measured, not attributed
The platform’s attributed revenue is shown and labeled. The result is the holdout, even when it’s smaller.
A record of every step
Who approved what, which words, which model, when. Written once and never edited.
Where it is today
Built in the open, stated as it stands.
As of September 29, 2026. This page changes when the software does.
The free Klaviyo audit at growthlegend.com is this part. From a read-only key it maps every flow and its timing, the campaigns and the lists, and finds the gap between a customer’s first order and their second.
Built and tested against a simulated account. It has not touched a real one. Its first live run is on an account I own, drafts only.
The holdout made in your account, the test registered before launch, and the readout when the customers have had time to come back.
For consumer brands selling direct on Shopify and Klaviyo. The price isn’t set. The list hears it first.
Before then
The method is free. The software runs it.
The Klaviyo audit
The first part of the software, from a read-only key. Your flows, your timing and your second-order clock.
Run it → Free, no formThe Second Order
The book the software is built on: why the second order decides everything after it, and how to get it.
Read it → By hand, nowThe Second-Purchase Sprint
If you want the work done on your account before the software opens, this is how I run it today.
See the Sprint →