CrossrefRest SDK

Crossref REST API client, generated from the OpenAPI spec.

The Crossref REST API allows users to search and retrieve metadata for scholarly works, including DOIs, ISSNs, and funder identifiers.

Learn more about Crossref REST API at api.crossref.org/swagger-ui/index.html.

This is an unofficial SDK for the Crossref REST public API, generated by Voxgig with @voxgig/sdkgen. It is not affiliated with, endorsed by, or sponsored by the upstream API provider.

Learn more about Voxgig SDKs at voxgig.com/sdk.

Metadata kindly supplied by www.freepublicapis.com.

TypeScript, Python, PHP, Golang, Ruby, Lua SDKs, a CLI, an interactive REPL, and an MCP server for AI agents — all generated from one OpenAPI spec by @voxgig/sdkgen.

Entities, not endpoints

This SDK exposes the API as a small set of semantic entities — Funder, Journal, Member, Type and Work — that you call directly, instead of assembling URL paths and query strings. Entities are Capitalised to mark them as the primary surface, each with the operations they support (load):

const client = new CrossrefRestSDK()
const funder = await client.Funder().load()

Thinking in entities keeps the mental model small — for people and AI agents alike — rather than reasoning about raw HTTP routes and query parameters.

Offline unit testing

Every SDK ships a built-in test mode that swaps the HTTP transport for an in-memory mock, so your unit tests run fully offline — no server, no network, and no credentials:

TypeScript

const client = CrossrefRestSDK.test()
const funder = await client.Funder().load({ id: 'test01' })
// funder is a bare Funder populated with mock data
console.log(funder)

Python

client = CrossrefRestSDK.test()
funder = client.Funder().load({"id": "test01"})
print(funder)

PHP

// Seed fixture data so offline calls resolve without a live server.
$client = CrossrefRestSDK::test([
    "entity" => ["funder" => ["test01" => ["id" => "test01"]]],
]);
$funder = $client->Funder()->load(["id" => "test01"]);

Golang

client := sdk.Test()
result, err := client.Funder(nil).Load(
    map[string]any{"id": "test01"}, nil,
)

Ruby

# Seed fixture data so offline calls resolve without a live server.
client = CrossrefRestSDK.test({
  "entity" => { "funder" => { "test01" => { "id" => "test01" } } },
})
funder = client.Funder.load({ "id" => "test01" })

Lua

local client = sdk.test()
local result, err = client:Funder():load({ id = "test01" })

Packages

Quickstart

TypeScript

import { CrossrefRestSDK } from '@voxgig-sdk/crossref-rest'

const client = new CrossrefRestSDK()

// Load funder data (returns a Funder)
const funder = await client.Funder().load()
console.log(funder)

See the TypeScript README for the full guide.

Surfaces

Use it from an AI agent (MCP)

The generated MCP server exposes every operation in this SDK as an MCP tool that Claude, Cursor or Cline can call directly. Build and register it:

cd go-mcp && go build -o crossref-rest-mcp .

Then add it to your agent’s MCP config (Claude Desktop, Cursor, etc.):

{
  "mcpServers": {
    "crossref-rest": {
      "command": "/abs/path/to/crossref-rest-mcp"
    }
  }
}

Entities

The API exposes 5 entities:

The operations available across these entities are load — see each entity’s own list above for exactly which it supports.

Quickstart in other languages

Python

from crossrefrest_sdk import CrossrefRestSDK

client = CrossrefRestSDK()


# Load a specific funder (returns the record, raises on error)
funder = client.Funder().load({"id": "example_id"})
print(funder)

PHP

<?php
require_once 'crossrefrest_sdk.php';

$client = new CrossrefRestSDK();


// Load a specific funder (returns the bare record; throws on error)
$funder = $client->Funder()->load(["id" => "example_id"]);
print_r($funder);

Golang

import sdk "github.com/voxgig-sdk/crossref-rest-sdk/go"

client := sdk.New()

// Load funder data
funder, err := client.Funder(nil).Load(map[string]any{"id": "example_id"}, nil)
if err != nil {
    panic(err)
}
fmt.Println(funder)

Ruby

require_relative "CrossrefRest_sdk"

client = CrossrefRestSDK.new


# Load a specific funder (returns the bare record; raises on error)
funder = client.Funder.load({ "id" => "example_id" })
puts funder

Lua

local sdk = require("crossref-rest_sdk")

local client = sdk.new()


-- Load a specific funder
local funder, err = client:Funder():load({ id = "example_id" })
print(funder)

Direct and prepare

For endpoints the entity model doesn’t cover, use the low-level methods:

• direct(fetchargs) — build and send an HTTP request in one step.
• prepare(fetchargs) — build the request without sending it.

Both accept a map with path, method, params, query, headers, and body. See the How-to guides below.

How-to guides

Make a direct API call

When the entity interface does not cover an endpoint, use direct:

TypeScript:

const result = await client.direct({
  path: '/api/resource/{id}',
  method: 'GET',
  params: { id: 'example' },
})
if (result instanceof Error) {
  throw result
}
console.log(result.data)

Python:

result = client.direct({
    "path": "/api/resource/{id}",
    "method": "GET",
    "params": {"id": "example"},
})

PHP:

$result = $client->direct([
    "path" => "/api/resource/{id}",
    "method" => "GET",
    "params" => ["id" => "example"],
]);

Go:

result, err := client.Direct(map[string]any{
    "path":   "/api/resource/{id}",
    "method": "GET",
    "params": map[string]any{"id": "example"},
})
if err != nil {
    panic(err)
}
fmt.Println(result)

Ruby:

result = client.direct({
  "path" => "/api/resource/{id}",
  "method" => "GET",
  "params" => { "id" => "example" },
})

Lua:

local result, err = client:direct({
  path = "/api/resource/{id}",
  method = "GET",
  params = { id = "example" },
})

Advanced

Everyday use only needs the sections above. This explains the internals behind every call — relevant when writing custom features.

Every SDK call runs the same five-stage pipeline:

1. Point — resolve the API endpoint from the operation definition.
2. Spec — build the HTTP specification (URL, method, headers, body).
3. Request — send the HTTP request.
4. Response — receive and parse the response.
5. Result — extract the result data for the caller.

A feature hook fires at each stage (e.g. PrePoint, PreSpec, PreRequest), so features can inspect or modify the pipeline without forking the SDK.

Features

Pass custom features via the extend option at construction time.

Per-language documentation

• TypeScript
• Python
• PHP
• Golang
• Ruby
• Lua

Upstream API

This SDK is generated from the upstream OpenAPI specification. It is an unofficial client and is not affiliated with the API provider.

• Upstream API: https://www.crossref.org/documentation/retrieve-metadata/rest-api/

Security

Please report security issues to security@voxgig.com. See SECURITY.md. Do not open public issues for suspected vulnerabilities.

Generated from the Crossref REST API OpenAPI spec by @voxgig/sdkgen.