Feeds and data

Every sign on Road Sign Math is open to read. Follow new signs in a feed reader, or build something with them: a map, a quiz, a bot, a mashup. No key, no sign-up.

• Feeds/feed.xmlNew signs, Atom and JSON Feed
• Every sign/signs.jsonNumbers, ways, places, finders, photos
• Players/players.jsonCounts, states, signs and badges
• On a map/signs.geojsonA point for every sign
• The API/api/v1Public JSON reads, OpenAPI
• For agents/llms.txtThe site in words, for AI tools

Feeds

The newest 50 signs, each with its photos, the math, who found it, when and where, and any other ways to make it true. Paste the address into any feed reader.

• Atom: https://roadsignmath.xyz/feed.xml
• JSON Feed 1.1: https://roadsignmath.xyz/feed.json
• One player’s signs: /players/<handle>/feed.xml and feed.json, linked from each player’s page.

A sign’s item is dated when it was posted and updated when someone adds a way. Readers find the feeds on their own from any page here.

Every sign

https://roadsignmath.xyz/signs.json has every sign on the map, newest posted first, with everything its page shows. It opens from any web page: it is served with Access-Control-Allow-Origin: *.

const res = await fetch('https://roadsignmath.xyz/signs.json');
const { signs } = await res.json();
for (const sign of signs) {
  console.log(sign.title, sign.ways[0]?.text ?? 'not solved yet');
}

The file

Each of the three files starts with the same fields, then its list: signs, players or features.

A sign

An example

The newest sign, cut to two of its numbers, its first way and one photo:

{
  "id": "01K43VJQP8H8787XQXQDW47W0B",
  "slug": "i-35w-at-82nd-street",
  "url": "https://roadsignmath.xyz/signs/i-35w-at-82nd-street",
  "title": "I-35W at 82nd Street",
  "caption": "Tyler found this one driving up I-35W.",
  "found_on": "2025-09-01",
  "posted_at": "2025-09-02T00:00:13.000Z",
  "updated_at": "2025-09-02T00:00:13.000Z",
  "posted_by": "jamie",
  "place": {
    "label": "I-35W at 82nd Street, Bloomington, Minnesota",
    "state": "MN",
    "lat": 44.857,
    "lng": -93.29,
    "approximate": true
  },
  "numbers": [
    {
      "value": "2",
      "text": "HOV 2+",
      "why": "Read as 2",
      "box": null
    },
    {
      "value": "6",
      "text": "6AM-10AM",
      "why": "Times split in two",
      "box": null
    }
  ],
  "finders": [
    {
      "name": "Tyler",
      "handle": "tyler",
      "url": "https://roadsignmath.xyz/players/tyler",
      "role": "found"
    }
  ],
  "way_count": 1,
  "ways": [
    {
      "text": "(90 − 82) ÷ 8 × 1 × 2 = 6 ÷ (10 − 7)",
      "tex": "\\frac{90 - 82}{8} \\times 1 \\times 2 = \\frac{6}{10 - 7}",
      "value": "2",
      "numbers": [
        "90",
        "82",
        "8",
        "1",
        "2",
        "6",
        "10",
        "7"
      ],
      "by": {
        "handle": "tyler",
        "name": "Tyler",
        "url": "https://roadsignmath.xyz/players/tyler"
      },
      "created_at": "2025-09-02T00:00:13.000Z"
    }
  ],
  "photos": [
    {
      "id": "01k43vjqp8x8n82dwwwbbwgwhp",
      "width": 1600,
      "height": 1201,
      "alt": "Overhead signs on I-35W: Express Lane (E-ZPass or HOV 2+ only, 6AM-10AM Mon-Fri), Exit 8 82nd St 1 mile, and Exit 7B 90th St.",
      "url": "https://roadsignmath.xyz/p/01k43vjqp8x8n82dwwwbbwgwhp/large.jpg",
      "thumb_url": "https://roadsignmath.xyz/p/01k43vjqp8x8n82dwwwbbwgwhp/thumb.jpg"
    }
  ]
}

Players

https://roadsignmath.xyz/players.json has everyone with a sign or a badge on the map, most signs first: what their page shows, and never an email address.

On a map

https://roadsignmath.xyz/signs.geojson is a GeoJSON FeatureCollection with a point for every sign that has a place, ready for Leaflet, MapLibre, QGIS or geojson.io. Most points are the town, not the exact spot. A sign nobody can place is left out; it is still in signs.json, with null coordinates.

The API

The iPhone app reads and posts through the API at https://roadsignmath.xyz/api/v1, version 1.7.0. These reads are public, JSON with snake_case keys. Its full description is OpenAPI 3.1 at /api/v1/openapi.json. Signing in and posting are for the app. The API is for apps and servers; from a web page, use the files above, which any site can fetch.

• GET /api/v1The API version and how many signs, players and states there are
• GET /api/v1/openapi.jsonThis description
• GET /api/v1/signsThe latest signs, newest first
• GET /api/v1/signs/nearSigns nearest a point
• GET /api/v1/signs/similarSigns that may be this one
• GET /api/v1/signs/{id}One sign and its ways
• GET /api/v1/mapEvery sign with a pin, for the map
• GET /api/v1/playersWho’s playing
• GET /api/v1/players/{handle}One player, their signs and their badges
• GET /api/v1/badgesEvery badge there is

For agents

• /llms.txt: the game, the pages, the files, the feeds and every sign in a line, for AI tools.
• /llms-full.txt: every sign in full, with the numbers, every way and what each photo shows.
• /sitemap.xml: every page.
• Microformats: Home is an h-feed, each sign page an h-entry (its name, photo, place, finders and math as LaTeX) and each player page an h-card, so any microformats parser can read them.

Using it

• Everything here is cached for a minute, so there’s no need to fetch it more often. For a feed, once an hour is plenty.
• The format of the files is their version. Fields may be added; renaming or removing one moves the version on. The API says its version in the API-Version header.
• Only signs on the map are here. A sign that is held back or hidden never is.
• Everything here, the signs, the math, the places, the names and the photos, is shared under CC BY 4.0: use it for anything, as long as you credit the sign’s finders and Road Sign Math, and link to the sign’s page. The site’s code is open source under the MIT licence.