A dev panel that knows why the experiment isn't running
Generic devtools show you state. The Toolbox dev panel cross-references the trigger contract, the targeting condition and live attributes — and names the exact clause blocking enrolment.
The blog
Notes from the experimentation trenches.
Twelve years of A/B testing — plus older JavaScript and performance notes going back to 2011 — written down so I don't have to remember it all.
Posts
Provisioning GrowthBook experiments over REST
The GrowthBook MCP keeps an agent on rails — drafts only, no raw targeting. When you need fully-targeted experiments across several clients, reproducibly, that turns out to be a REST job. Here's what I learned wiring it up.
![A three-step checkout — Cart, Delivery, Payment — with the progress bar hidden only on Payment via a single reactive .checkout-steps:has(.step:last-child[aria-current=step]) rule](/_astro/cover.CMRAJcMM_206BkE.svg)
Hide an element on just one step of a client-side checkout with :has()
An A/B test that had to remove the progress bar on the final checkout step only — on a checkout that re-renders itself. Why the JS approach kept losing, and the one reactive CSS rule that won.
The control cohort problem: tracking GrowthBook URL-redirect experiments
A GrowthBook redirect is an auto-experiment the SDK applies client-side — so getFeatureValue returns -1, your render callback ignores it, and the control cohort quietly vanishes from your data. Here's the asymmetry, the SRM trap underneath it, and the paired A-A tracker that fixes both.
Fix vertical text alignment in a flex box with CSS text-box-trim
A fixed-height label whose all-caps text looked too high — even though getBoundingClientRect() swore it was centred. Why the box lies, how to measure the actual glyph ink, and the text-box-trim property that finally fixed it.
reboot. rethink. recoveryArea.
Twenty-three years online, four CMSes, one static-site flip. Why we moved off WordPress to Astro on Cloudflare Pages — and whether that's the right call for your own site too.
Letting an LLM read my release notes
A weekly npm audit that uses my existing CLI session to read release notes and decide what's safe to auto-update — zero extra API cost.
From Joomla to Astro: twenty-three years on the open web
Joomla in 2003, SilverStripe briefly, a long WordPress decade with Genesis on top — and why static-site tooling finally won me over for new builds in 2026.
Three Jiras, three GrowthBooks, one MCP pattern
One MCP script + one .env per client + auto-detected auth. The pattern that keeps QLF, Toom, and LAB strictly isolated without ever mixing tenants.
Forcing variations without breaking targeting
GrowthBook's native URL override bypasses every targeting rule. The QA preview tool I built keeps the rules in place — forcing only fires if the user already qualifies.
How to detect user-defined window globals with JavaScript (Enhanced)
An async, error-resilient globals detector: spins up an iframe baseline, categorises the diff by type, and lets you exclude known third-party noise.
Building the ultimate A/B testing developer experience
How a Vite hub, a Chrome extension that hijacks production scripts, and a WebSocket reload loop turned multi-client A/B testing into hot-reloadable dev work.
Building a developer-friendly Chrome extension: script redirector with live reload
Inside MintMinds RequestLite: a Manifest V3 Chrome extension that redirects production script URLs to localhost and live-reloads tabs over WebSocket.
How to list user-defined window globals with JavaScript
A tiny IIFE that compares window against a fresh iframe to list every user-defined global, grouped by type — handy for auditing third-party noise.
How to simulate clicks on non-supported HTML elements
Why HTMLElement.click() silently fails on SVG, and the modern MouseEvent-dispatch one-liner that actually triggers the click on any element.
Adding DOM elements LIKE A BOSS
A tiny config-driven helper that builds, attributes, and inserts DOM nodes in one call — the primitive that powers most of my A/B test variants.
My secret to super-fast A/B test loading
How wrapping querySelector in a MutationObserver kills the FOUC in A/B tests — your variant fires the instant the target element lands in the DOM.
Notify enter viewport the proper way: Intersection Observer
Replacing my old rAF-based viewport tracker with IntersectionObserver — the simpler, lazier, dramatically less complicated way to fire A/B test events.
Notify enter viewport
The original requestAnimationFrame helper that fires A/B test events when an element scrolls into view — predecessor to the Intersection Observer rewrite.
A/B test jQuery performance cheat sheet
Five jQuery techniques that keep A/B tests under their performance budget — selector speed, caching, chaining, event delegation, and DOM-write batching.
Track that!
A pocket-sized click introspection helper that JSON-stringifies the source element, its index, text, and every attribute — useful as A/B test custom tracking.
A smarter console.info
A tiny defensive wrapper that picks console.dir for objects and arrays and console.info for primitives — back when Firebug and Chrome disagreed about logging.