Shopify
Cloudflare Workers
Klaviyo
Slack
Google Analytics 4
Microsoft ClarityFlags
Read a flag
One call on the theme, a header on headless.
For in-house engineers
Full control in code, with the statistics done
CSS and JavaScript per group, feature flags, Next.js and Cloudflare installs, a dataLayer event and an API with scoped keys.
middleware.ts
import { croMiddleware } from "@growthdept/cro-runtime/headless"; export default async function middleware(req, ev) { // the group is decided here, before the page renders return (await croMiddleware(req, ev, { publicKey: process.env.CRO_PUBLIC_KEY, })) ?? NextResponse.next();}
What gets in the way
What engineers usually get from a testing tool
A heavy script
A tag that loads after the page and swaps content in front of the shopper.
A closed box
No way to create or read tests from code.
Theme only
Nothing for a headless storefront or a page Shopify does not serve.
How Growth Dept CRO helps
Built for the way you ship
Decided before paint
On a theme the set-up is inlined, under 6 KB gzipped; on headless the middleware decides on the server.
Code per group
CSS and JavaScript on any group, up to 8 KB each; flags read with window.CRO.flag().
An API and webhooks
Create drafts, start and end tests, read results; signed webhooks for each step.
What you get
The pieces engineers ask for
Events
Your own goals
window.CRO.track() sends a custom event a test can count.
API
Scoped keys
Keys carry only the scopes you choose.
Webhooks
Signed deliveries
HMAC-SHA256 over the timestamp and body.
Find out what is worth testing on your store.
Book a 45-minute call with the Growth Dept team. We look at your store and your traffic, and tell you which tests to run first.