The Glucose Diaries

A static, client-side visualizer for 9,515 continuous glucose readings I collected over six weeks wearing a Dexcom Stelo. It’s a React and TypeScript single-page app served from GitLab Pages — no backend, no database. The dataset ships as a static asset and every interaction (zoom, pan, annotation lookup) happens in the browser, which keeps the site fast and free to host.

The detail I cared most about was shareable deep links. The chart encodes its entire view state in the URL as query parameters — start and end as epoch-millisecond bounds, plus an optional note string for the annotation label. That means any specific moment in the data can be linked to directly: the basketball adrenaline spike, a fasting stretch, an overnight baseline window. The accompanying write-up uses this heavily — each section drops the reader into the exact time window it’s describing, so the prose and the chart stay in sync without screenshots that go stale.

The data itself is messy in ways the visualization has to respect. The Stelo sensors failed early and often — each lasted about five days against a rated fifteen — so the trace has real gaps between sensor changes rather than interpolated straight lines that would imply readings that don’t exist. There’s also a measurement floor at 70 mg/dL, where the device reports <70 rather than a true value, and a warm-up window after each sensor placement where readings are unreliable. The chart preserves all of it untrimmed and surfaces annotations on the moments where a spike or drop is more plausibly a sensor artifact than a real glucose event, so the visualization stays honest about the difference between physiology and hardware noise.

The visualizer is the companion piece to a written analysis of the dataset — seven moments where the biology showed up clearly, from why lifting weights raises blood sugar while running lowers it, to what a fasting day’s flat trace reveals about baseline liver metabolism. The full write-up, with the mechanisms and sourced comparisons to published CGM literature, lives here: The Glucose Diaries: What My CGM Revealed About My Biology.