A handheld-encyclopedia deck for real wildlife. Enter a US ZIP code and every species people logged on iNaturalist within 10 km this week becomes a collectible card, rarest first.
How it works · Under the hood · Data · Run it
Most of what lives around you has been photographed by somebody, and a surprising amount of it almost never is. Field Dex turns a week of community sightings into a deck: the dove on your feeder is Common, the fly someone caught on a leaf down the road might be one of a few hundred ever logged on Earth. That one goes first.
low smartweed (Persicaria longiseta) · Uncommon · seen 1× today, 1 of 51,726 ever logged · iNaturalist page
Photo: (c) Brad Walker, some rights reserved (CC BY-NC), uploaded by Brad Walker. Updated every evening by a GitHub Action: it asks iNaturalist for every species logged within 10 km of Evansville that day and keeps the one with the fewest observations worldwide. Every day's pick is logged in docs/daily-dex.csv.
| Search | A ZIP (looked up on Zippopotam.us) or your browser's location becomes a point. One request to iNaturalist's species_counts returns every species observed within 10 km in the last 7 days. |
| Type | The species' iconic group picks its type: birds are Flying, plants Grass, insects and spiders Bug, fungi Poison, mammals Normal, reptiles Dragon, amphibians, fish and molluscs Water, anything else Mystery. |
| Rarity | The global observation count sets the tier: under 2,000 Legendary, under 10,000 Rare, under 100,000 Uncommon, else Common. Catch difficulty is the same number on a log scale, 5 stars at 1,000 or fewer down to 1 star at a million. |
| Flip | Tap a card to turn it over: the back is its dex entry (the Wikipedia summary iNaturalist keeps, plus class, order and family), fetched on the first flip. Mark it caught and a Caught counter tracks your collection in this browser. |
| Foil | Rare and Legendary cards are holographic: the foil follows your pointer and the card tilts toward it. Pure CSS driven by two custom properties; off under prefers-reduced-motion. |
| Share | Searching by ZIP puts it in the address bar, so ?zip=47708 links straight to a deck. |
| A README that updates itself | Every evening a GitHub Action finds the rarest species logged near Evansville, IN that day and puts it at the top of this page (docs/daily-dex.csv keeps the history). |
- Fully static. No backend, no database, no keys: the page calls iNaturalist and Zippopotam.us straight
from the browser (both allow any origin), and
next buildexports plain HTML. - One request per search. iNaturalist asks clients to stay near 60 requests a minute, so there's no polling or prefetching. It returns up to 200 species per request; denser areas show the 200 most-logged and say so.
- No UI libraries. The look (palette, panel frames, bevelled badges, tab rail, grid paper) is sampled from
DS-era handheld encyclopedia screens and written down in
DESIGN.md. Pixel stars and the leaf icon are drawn from strings ofXs. - Plain-assert checks.
lib/dex.check.tspins the tier thresholds, the star scale and the type map.
| Path | What's there |
|---|---|
lib/dex.ts |
Types, rarity thresholds, catch stars, API URLs (shared with the daily bot) |
components/FieldDex.tsx |
Search, every state (loading, empty, unknown ZIP, location denied, retry), type filter |
components/DexCard.tsx |
The card: front, flip-side entry, caught toggle, pointer-driven foil |
scripts/daily-dex.mjs + .github/workflows/daily-dex.yml |
The self-updating README |
Sightings, taxa and photos from iNaturalist, a joint initiative of the California Academy of Sciences and the National Geographic Society. Photos are Creative Commons and every card shows its photographer's attribution. ZIP lookup by Zippopotam.us. Field Dex is a fan-made idea riff, not affiliated with any game or franchise.
npm install
npm run dev # http://localhost:3000Checks (Node 22.18+): npm run typecheck, npm run check. Run the daily bot by hand with
node scripts/daily-dex.mjs (set DAY=YYYY-MM-DD for another day).