Same store. Two builds. One phone.
Negative Split is a fictional running store. The same product page, built two ways, loads side by side on a simulated phone connection. Press start, tap around while it loads, then try fixing the slow one.
Fixes changed. Start the race again to see the difference.
Tap Add to cart in either phone while they load.
See every file, second by second
Hand-built
Typical build
Fix the typical build
Pick what to fix, then race again. You'll get most of the way there. Not all of it.
Under the hood
What this demo shows.
Speed isn't a setting you switch on. It's every file a page asks for, and in what order.
File sizes, simulated network
Each build is a list of real-world files with real sizes. They download through a model of a phone connection that shares bandwidth, pays for each new server connection and runs scripts one at a time.
Google's line for loading
The race scores both pages on Google's Core Web Vitals: the main content should show within 2.5 seconds, and the layout should barely move.
Less to download
About 280 KB against about 3 MB, close to the 2.3 MB the median mobile page weighs today.
Fixes you can try
Most slow sites can be improved a lot without a rebuild. The toggles show how much, and where the ceiling is.
Taps ignored
Tap Add to cart while the typical build loads: the phone is busy running scripts and the tap waits. The hand-built page's button is a plain form that works right away.
Brand, made for the demo
Negative Split was designed for this page: logo, palette, type and product art, all drawn in code.
Negative Split is fictional. The race is a simulation built on real-world file sizes and Google's published test settings (1.6 Mbps, 150 ms latency), not a recording of real sites. Scripts are timed for a mid-range phone.
The brand
Meet Negative Split.
A fictional running store in Portland, designed for this demo. A negative split is running the second half of a race faster than the first. The mark is a circle cut on the diagonal, its second half a step ahead.
- Violet#5B3DF5
- Sun#FFD23F
- Fog#EEF0F3
- Ink#15131C
- Slate#5D5A6B
Built for the back half.
Bricolage Grotesque for headlines. Instrument Sans for everything you read. A mono for the numbers runners care about.
Mile 18 · 7:42 /mi · 228 g
- "Built for the back half."
- "Foam that still feels like foam at mile 18."
- "Returns for 60 days. Run in them first."