JSON API

The API returns the same data as the MCP tools, as JSON. It needs no key and allows requests from any origin.

GET /api/topics#

Every topic with its region, signals and sources.

curl -s https://contextatlas.dev/api/topics

{
  "updatedAt": "2026-10-23",
  "topics": [
    {
      "id": "vercel",
      "name": "Vercel",
      "role": "Hosting",
      "signals": [{ "type": "file", "pattern": "vercel.json" }],
      "sources": [{ "kind": "mcp", "title": "Vercel MCP server", "url": "https://vercel.com/docs/mcp/vercel-mcp" }],
      "region": { "id": "cloud", "name": "Cloud providers" }
    }
  ]
}

GET /api/topics/:id#

One topic by id.

curl -s https://contextatlas.dev/api/topics/hono

Returns { "updatedAt": "…", "topic": { … } }. An unknown id returns 404 with an error message.

GET /api/search#

Full-text search, the same as the MCP tool search. Every word must match, as a prefix.

Parameter	Type	Description
q	required, 1 to 200 characters	Words to search for
kind	optional	llms, full, docs, mcp, skill, rules or guide
limit	optional, 1 to 50	Maximum number of topics, default 10

curl -s 'https://contextatlas.dev/api/search?q=vercel&kind=mcp&limit=2'

{
  "query": "vercel",
  "results": [
    {
      "topic": { "id": "vercel", "name": "Vercel", "role": "Hosting" },
      "sources": [{ "kind": "mcp", "title": "Vercel MCP server", "url": "https://vercel.com/docs/mcp/vercel-mcp" }],
      "score": -6.1
    }
  ]
}

Invalid parameters return 400 with an error message that names the parameter.

Caching#

Responses carry Cache-Control headers: topics for an hour in the browser and a day at the CDN, search results for five minutes. The catalog changes only with a deploy, so there is no need to poll.

Other formats#

• /atlas.json: the whole catalog in one file, grouped by region, with each topic's llmsTxt URL
• /llms.txt and /llms/<id>.txt: the same data as Markdown for agents

Typed client#

The API is a Hono app, and its route types are exported as AppType. TypeScript projects in this repository can use the typed client:

import type { AppType } from "@contextatlas/server";
import { hc } from "hono/client";

const api = hc<AppType>("https://contextatlas.dev");
const res = await api.api.topics[":id"].$get({ param: { id: "cloudflare" } });