> ## Documentation Index
> Fetch the complete documentation index at: https://hexagraph-docs.voyla.in/llms.txt
> Use this file to discover all available pages before exploring further.

# Hexagraph — Scholarly Metadata API Gateway Overview

> Hexagraph is a high-performance academic data gateway with unified REST and GraphQL APIs for querying scholarly works, authors, sources, and institutions.

Hexagraph is a high-performance scholarly metadata gateway that curates and aggregates academic data from [OpenAlex](https://openalex.org), [Crossref](https://www.crossref.org), and other open research platforms — exposing it through a single, unified interface. Whether you need REST endpoints for structured data retrieval or a GraphQL API for flexible, nested queries, Hexagraph gives you enriched, consistent access to millions of scholarly works, authors, sources, institutions, publishers, and funders without managing multiple upstream integrations.

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/quickstart">
    Make your first REST and GraphQL requests in under 5 minutes.
  </Card>

  <Card title="API Reference" icon="code" href="/api-reference/overview">
    Explore all available REST endpoints, parameters, and response schemas.
  </Card>

  <Card title="Search Outputs" icon="magnifying-glass" href="/guides/search-outputs">
    Learn how to search, filter, and paginate scholarly publications.
  </Card>

  <Card title="GraphQL Overview" icon="diagram-project" href="/api-reference/graphql/overview">
    Query nested scholarly metadata with the Hexagraph GraphQL API.
  </Card>
</CardGroup>

## What Hexagraph provides

* **REST endpoints** for querying scholarly outputs, authors, sources, institutions, publishers, and funders
* **GraphQL playground** for composing flexible, nested queries against the full metadata graph
* **HX\_ID prefix system** — a consistent entity identifier scheme (e.g. `HX_W2107277218`, `HX_A5086208034`) used across all endpoints
* **Rate limiting** enforced at 30 requests per minute and 1,000 requests per day to maintain fair access for all users
* **Autocomplete** support for fast, typeahead-style lookups of entities by name or identifier
* **Root-level entity resolution** — resolve any `HX_ID` directly at the API root for quick cross-entity lookups

## Data Sources

Hexagraph aggregates and enriches scholarly metadata from two primary open-data sources:

* **[OpenAlex](https://openalex.org)** — A fully open catalog of global research outputs, authors, institutions, and concepts, maintained by OurResearch. Hexagraph draws on OpenAlex for its broad coverage of works, citation relationships, and author profiles.
* **[Crossref](https://www.crossref.org)** — The official DOI registration agency for scholarly publishing. Crossref metadata enriches Hexagraph records with accurate DOIs, publisher details, funder information, and bibliographic data.

Together, these sources give Hexagraph broad, reliable coverage of the scholarly record while remaining grounded in open, freely accessible infrastructure.

<Note>
  The Hexagraph API is **open access** — no API key or authentication token is required to make requests. Rate limiting is enforced per IP address to ensure fair usage across all consumers. See the [Authentication](/authentication) page for details on limits and best practices.
</Note>