NASA ADS API Guide

NASA ADS API Guide

Overview

The NASA Astrophysics Data System (ADS) is a digital library operated by the Smithsonian Astrophysical Observatory under a NASA grant. It is the primary bibliographic database for astronomy and astrophysics, also covering significant portions of physics, geophysics, and related disciplines. ADS indexes over 16 million records and provides access to full-text articles, citations, and usage metrics.

ADS is indispensable for astronomers and physicists. Nearly every paper in astrophysics is indexed in ADS, and the system provides powerful search capabilities including full-text search, citation and reference tracking, author disambiguation, and object-level queries (search by astronomical object name). The database integrates with SIMBAD, NED, and other astronomical databases to link publications to the celestial objects they study.

The ADS API requires a free API token and supports 3,000 requests per day. It returns JSON and supports a rich query language with field-specific searches, boolean operators, and positional queries.

Authentication

Authentication is required via a free API token. Register at https://ui.adsabs.harvard.edu/user/settings/token to generate your token. Include it in every request as a header:

Authorization: Bearer YOUR_ADS_API_TOKEN

Tokens do not expire but can be regenerated from the settings page. Each token is associated with a user account and is subject to per-account rate limits.

Core Endpoints

Query: Search the ADS Database

• URL: GET https://api.adsabs.harvard.edu/v1/search/query
• Parameters:

  Param	Type	Required	Description
  q	string	Yes	Search query (ADS query syntax with field qualifiers)
  fl	string	No	Fields to return (comma-separated: title, author, year, bibcode, doi, citation_count, abstract, etc.)
  rows	integer	No	Results per page (default: 10, max: 2000)
  start	integer	No	Pagination offset (default: 0)
  sort	string	No	Sort field and order (e.g., citation_count desc, date desc)
  fq	string	No	Filter queries for faceting (e.g., database:astronomy)

• Example:

  curl -H "Authorization: Bearer YOUR_TOKEN" \
       "https://api.adsabs.harvard.edu/v1/search/query?q=gravitational+waves&fl=title,author,year,bibcode,citation_count,doi&rows=10&sort=citation_count+desc"
  

• Response: JSON with response.numFound (total hits) and response.docs array. Each doc contains the requested fields. The bibcode is the unique ADS identifier (19-character string encoding journal, year, volume, and page).