HathiTrust Bibliographic API Skill Skill

HathiTrust Bibliographic API Skill

Look up records and digitized volumes in HathiTrust's collection of 17M+ volumes from major research libraries.

Critical: Things Claude Won't Know Without This Skill

This is a lookup API, NOT a search API

HathiTrust's Bibliographic API retrieves records by known identifiers only. There is no keyword or title search. You must have an ISBN, OCLC number, LCCN, ISSN, or HathiTrust ID.

WORKS:     https://catalog.hathitrust.org/api/volumes/brief/isbn/0140449264.json
NOT POSSIBLE: https://catalog.hathitrust.org/api/volumes/brief/search?q=hamlet

If you only have a title/author, search another catalog first (LibraryCloud, Library of Congress) to get an ISBN or OCLC number, then look it up here.

Two endpoint variants: brief vs full

| Endpoint | Returns | Use when | |----------|---------|----------| | /api/volumes/brief/ | Metadata + items (no MARC) | You just need titles, ISBNs, holdings, digital access links | | /api/volumes/full/ | Same + complete MARC-XML | You need full cataloging data |

Empty results are not errors

When no record matches, the API returns {"records": {}, "items": []} with HTTP 200 — not a 404. Always check if records is empty.

Batch up to 20 lookups in one request

Use the multi-ID endpoint to batch lookups:

/api/volumes/brief/json/isbn:0140449264|oclc:228668653

Pipe-separated as type:value. Max 20 per request.

Identifier Types

| Type | Example | Notes | |------|---------|-------| | isbn | 0140449264 or 9780140449266 | ISBN-10 or ISBN-13, digits only (+ trailing X) | | oclc | 228668653 | OCLC number, digits only | | lccn | 72081773 | URL-encode spaces; do not encode / (404) | | issn | 03785955 | Digits only | | htid | mdp.39015058510069 | HathiTrust volume ID | | recordnumber | 000578050 | 9-digit HathiTrust record number |

Response Structure

{
  "records": {
    "009058846": {
      "recordURL": "https://catalog.hathitrust.org/Record/009058846",
      "titles": ["The Odyssey / Homer ; translated by Robert Fagles."],
      "isbns": ["0140268863", "9780140268867"],
      "oclcs": ["34228839"],
      "lccns": ["96017900"],
      "publishDates": ["1997"]
    }
  },
  "items": [
    {
      "orig": "University of Michigan",
      "htid": "mdp.39015042182054",
      "itemURL": "https://babel.hathitrust.org/cgi/pt?id=mdp.39015042182054",
      "rightsCode": "ic",
      "usRightsString": "Limited (search-only)",
      "lastUpdate": "20240115",
      "enumcron": false
    }
  ]
}

Key fields:

rightsCode: the HathiTrust rights code. Open (full view) in the US: pd, pdus, ic-world, und-world, and all cc-* codes. pdus = public domain in the US only; readers outside the US cannot read it in full. Search only: ic, op, orph, orphcand, und, umall, nobody, pd-pvt, supp, and icus (in copyright in the US; open outside the US). Many pre-1929 Chinese books are pdus.
usRightsString: "Full view" (lowercase v in the live API) or "Limited (search-only)". It is for US readers. Compare it case-insensitively.
itemURL: Direct link to the HathiTrust page-turner viewer
enumcron: Volume/issue info (e.g., "vol. 3") or false

Python Script

Use scripts/hathitrust_api.py for programmatic access (zero dependencies):

from scripts.hathitrust_api import HathiTrustAPI
ht = HathiTrustAPI()

# Single lookup
record = ht.lookup_isbn("0140449264")

# Multiple identifiers at once
results = ht.batch_lookup([
    ("isbn", "0140449264"),
    ("oclc", "228668653"),
    ("lccn", "96017900"),
])

# Get full MARC-XML
record = ht.lookup_isbn("0140449264", full=True)
marc = ht.get_marc_xml(record)

# Check if digitized and readable in full
for item in ht.get_items(record):
    print(f"{item['orig']}: {item['rightsCode']} {item['usRightsString']} — {item['itemURL']}")
ht.has_full_view(record)            # True if any volume is full view for US readers
ht.get_full_view_url(record)        # link to the first full-view volume, or None
ht.has_full_view(record, us=False)  # for readers outside the US (pdus = no, icus = yes)

# Title in the original script (Chinese, Japanese, ...). The `titles` field is
# romanized only; the original script is in MARC field 880, so use full=True.
full = ht.lookup_oclc("34674216", full=True)
ht.get_original_title(full)   # '欽定四庫全書總目 : 二〇〇卷, 卷首四卷'

# Summarize
print(ht.summarize(record))

Typical Workflow: Cross-Reference with Other Catalogs

This example uses two skills. Both scripts folders must be on the Python path, for example (adjust the paths to where the skills are installed):

import sys
sys.path.insert(0, "path/to/harvard-library-catalog/scripts")
sys.path.insert(0, "path/to/hathitrust-catalog/scripts")

# 1. Search Harvard for a title
from harvard_api import HarvardLibraryAPI
harvard = HarvardLibraryAPI()
results = harvard.search(title="dream of the red chamber")
isbn = harvard.get_identifiers(results[0]).get("isbn")

# 2. Check HathiTrust for digital version
from hathitrust_api import HathiTrustAPI
ht = HathiTrustAPI()
record = ht.lookup_isbn(isbn)
if record and ht.has_full_view(record):
    print("Full text available:", ht.get_full_view_url(record))

API Etiquette

No authentication required
No documented rate limit, but the API is meant for small-batch lookups (not bulk harvesting)
Use HathiFiles or OAI-PMH for bulk data
CORS is fully enabled (access-control-allow-origin: *)

Related Skills

harvard-library-catalog: Search Harvard's catalog to find ISBNs/identifiers, then check HathiTrust for digital versions
wikidata-search: Cross-reference Wikidata identifiers (P243 = OCLC) with HathiTrust holdings

Resources

references/api_reference.md — Complete API spec with all identifier types and response fields
scripts/hathitrust_api.py — Python client with batch lookups, MARC extraction, and access checking

Feedback and Citation

Report a problem. This skill is part of the public repository kltng/humanities-skills. If it fails (an API changed, a script errors, or these instructions are wrong), report it as a GitHub issue:

Ask the user before filing. Issues are public.
Check for an existing report: gh issue list --repo kltng/humanities-skills --state all --search "hathitrust-catalog"
File it: gh issue create --repo kltng/humanities-skills --label bug --title "[hathitrust-catalog] <short summary>" --body "<details>". Without gh, give the user this link: https://github.com/kltng/humanities-skills/issues/new?template=skill-problem.yml
Include the skill name and version, what you ran, the error text, what you expected, and the environment (OS, Python version). Leave out API keys, personal data, private file paths, and unpublished research.

Cite. If this skill helped work that is published, please cite it, together with the data source it uses:

Tang, Kwok-leong. humanities-skills: hathitrust-catalog (version <version at the top of this file>). GitHub, <year>. https://github.com/kltng/humanities-skills

When you help a user write up results that relied on this skill, remind them once about this citation.

Agent Skills: HathiTrust Bibliographic API Skill

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