Hexagraph REST API Reference: Endpoints and Params

The Hexagraph API provides RESTful endpoints for querying enriched scholarly metadata across all 10 core entities. All endpoints are available at the base URL https://api.hexagraph.in and return JSON. The API is designed for high-performance, unified access to academic data across outputs, authors, institutions, sources, publishers, funders, topics, domains, fields, and subfields.

Base URL

https://api.hexagraph.in

All requests should be made over HTTPS. The API is versioned at 1.0 and the base URL already reflects the current stable version.

Authentication & Rate Limits

Open access — no API key required. You can start making requests immediately without credentials or registration. Requests are rate limited per IP address to ensure fair usage across all clients. See Rate Limits and GET /rate-limit for real-time monitoring.

Limit Category	Limit
Short-Burst IP Limit	30 requests / min
IP Daily Quota - List/Filter	500 requests / day
IP Daily Quota - Search	50 requests / day

Every API response includes rate limit status headers (X-RateLimit-IP-Limit, X-RateLimit-IP-Remaining, X-RateLimit-Daily-Remaining).

Content Type

All responses are returned as application/json. You do not need to set a request Content-Type header for standard REST GET requests. For GraphQL queries, send a POST request to /graphql with the header:

Content-Type: application/json

{
  "query": "{ output(id: \"HX_W3038568908\") { id name year cited_by_count } }"
}

Available Endpoints

Endpoint	Description
`GET /outputs`	List/search scholarly works
`GET /outputs/{id}`	Fetch a specific output by HX_W ID
`GET /authors`	List/search authors
`GET /authors/{id}`	Fetch a specific author by HX_A ID
`GET /sources`	List/search sources (journals, repositories)
`GET /sources/{id}`	Fetch a specific source by HX_S ID
`GET /institutions`	List/search institutions
`GET /institutions/{id}`	Fetch a specific institution by HX_I ID
`GET /publishers`	List/search publishers
`GET /publishers/{id}`	Fetch a specific publisher by HX_P ID
`GET /funders`	List/search funders
`GET /funders/{id}`	Fetch a specific funder by HX_F ID
`GET /domains`	List research domains
`GET /domains/{id}`	Fetch a specific domain by numeric ID
`GET /fields`	List research fields
`GET /fields/{id}`	Fetch a specific field by numeric ID
`GET /subfields`	List research subfields
`GET /subfields/{id}`	Fetch a specific subfield by numeric ID
`GET /topics`	List research topic clusters
`GET /topics/{id}`	Fetch a specific topic by HX_T ID
`GET /autocomplete`	Cross-entity autocomplete search
`GET /autocomplete/{entity}`	Entity-specific autocomplete
`GET /rate-limit`	View current client IP rate limit usage and daily quotas
`POST /graphql`	Execute a GraphQL query (`output`, `author`, `outputs`, etc.)

Common Query Parameters

The following parameters are available across list endpoints (e.g. /outputs, /authors, /institutions):

string

Filter expression to narrow results. Accepts key-value pairs such as is_oa:true or year:2024. Multiple filters can be combined with commas.

string

Sorting parameter to order results (e.g. cited_by_count:desc, outputs_count:desc, year:asc).

integer

Page number for pagination. Defaults to 1.

integer

Number of results returned per page. Allowed values: 10, 25, 50, 100. Defaults to 25.

Response Format

List Endpoints

List endpoints (e.g. GET /outputs, GET /authors) return a paginated envelope containing metadata and a results array:

{
  "meta": {
    "count": 1523,
    "db_response_time_ms": 12.4,
    "page": 1,
    "per_page": 25
  },
  "results": [
    {
      "id": "HX_W3038568908",
      "name": "Machine learning for molecular design and synthesis",
      "year": 2020,
      "cited_by_count": 1420
    }
  ]
}

Single-Entity Endpoints

Single entity lookups (e.g. GET /outputs/{id}, GET /authors/{id}) return the transformed entity object directly:

{
  "id": "HX_W3038568908",
  "doi": "https://doi.org/10.1038/s41586-020-2649-2",
  "name": "Machine learning for molecular design and synthesis",
  "year": 2020,
  "cited_by_count": 1420
}

ID System (`HX_`)

All entity identifiers use the HX_ prefix format:

Entity Type	Prefix / Format	Example ID
Output	`HX_W`	`HX_W3038568908`
Author	`HX_A`	`HX_A5028125522`
Source	`HX_S`	`HX_S140251998`
Institution	`HX_I`	`HX_I109009565`
Publisher	`HX_P`	`HX_P4310319965`
Funder	`HX_F`	`HX_F4320321001`
Topic	`HX_T`	`HX_T10346`
Domain	Numeric string	`3`
Field	Numeric string	`17`
Subfield	Numeric string	`1702`

Overview

REST Endpoints

GraphQL

Hexagraph REST API Reference: Endpoints and Params

Base URL

Authentication & Rate Limits

Content Type

Available Endpoints

Common Query Parameters

Response Format

List Endpoints

Single-Entity Endpoints

ID System (`HX_`)

​Base URL

​Authentication & Rate Limits

​Content Type

​Available Endpoints

​Common Query Parameters

​Response Format

​List Endpoints

​Single-Entity Endpoints

​ID System (HX_)

Base URL

Authentication & Rate Limits

Content Type

Available Endpoints

Common Query Parameters

Response Format

List Endpoints

Single-Entity Endpoints

ID System (`HX_`)