crates.io Config API

Registry configuration document

Operations 1

GET /config.json Get Registry Configuration #

Documentation

Specifications

Schemas & Data

Other Resources

Work with this as data

Every API here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for apis

7 MCP tools reach this
  • find_apisBrowse and filter every API in the catalog.
  • get_api_artifactsOne API's artifacts, grouped by type.
  • get_openapiThe primary OpenAPI for this API.
  • find_similar_apisAPIs that look like this one.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
This API
curl "https://apis.io/api/v1/apis/crates-io-config-api"
All apis
curl "https://apis.io/api/v1/apis?limit=25"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

A second provider on the same verified email joins the account you already have.

OpenAPI Specification

crates-io-config-api-openapi.yml Raw ↑
openapi: 3.2.0
info:
  title: crates.io Sparse Index Config API
  description: 'The crates.io sparse index serves per-crate metadata files over HTTP rather than requiring a clone of the legacy crates.io-index Git repository. Cargo uses the sparse protocol by default since Rust 1.70 (June 2023). The index also publishes a config.json document at the root and supports HTTP cache validation via ETag and Last-Modified.

    '
  version: v1
  contact:
    name: crates.io Team
    email: help@crates.io
    url: https://crates.io
  license:
    name: Cargo Documentation (MIT/Apache-2.0)
    url: https://doc.rust-lang.org/cargo/reference/registry-index.html
servers:
- url: https://index.crates.io
  description: crates.io Sparse Index (sparse+https://index.crates.io/)
tags:
- name: Config
  description: Registry configuration document
paths:
  /config.json:
    get:
      summary: Get Registry Configuration
      description: 'Returns the registry configuration document. Must be the first request a sparse-index client makes; controls download URL templates, publishing endpoint, and authentication requirements.

        '
      operationId: getRegistryConfig
      tags:
      - Config
      responses:
        '200':
          description: The registry configuration document.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RegistryConfig'
              example:
                dl: https://crates.io/api/v1/crates
                api: https://crates.io
                auth-required: false
components:
  schemas:
    RegistryConfig:
      type: object
      required:
      - dl
      properties:
        dl:
          type: string
          description: Download URL template for .crate files. Supports {crate}, {version}, {prefix}, {lowerprefix}, and {sha256-checksum} markers.
        api:
          type: string
          description: Base URL of the Web API used for publishing, yanking, owners, and search.
        auth-required:
          type: boolean
          description: Whether all index and download operations require an Authorization header.